Practice for Parturition: Does Sexual Activity Improve Labor and Birth Outcomes?

Abstract

Niles Newton, a prolific reproductive biologist, described physical, psychological, and hormonal similarities between female sexual response and childbirth. Such phenotypic overlap indicates shared mechanisms, which led Newton to suggest that dysfunction in one process could interfere with the other process. There currently exists very little research on how pre-birth female sexuality impacts subsequent parturition. We address this knowledge gap and extend Newton’s work by proposing that sexual activity provides opportunities for women to physically and psychologically prepare for childbirth, a process that we call “practice for parturition.” To introduce and describe the practice for parturition framework, we provide a detailed review of salient reflexes of the female genito-pelvis, as well as psychological states that facilitate both sexual pleasure and parturition. These physical and psychological mechanisms represent putative links between sex and birth that underpin our prediction that sexual activity provides birth preparation for women. We demonstrate the utility of the practice for parturition framework through three systematic reviews, evaluating the following hypotheses: (1) Pelvic floor interventions jointly improve sexual function and birth outcomes; (2) the presence of pre-birth sexual activity and/or sexual function predicts improved labor and birth; and (3) the presence of sexual dysfunction impairs birth outcomes. Results from our review provide notable evidence supporting the three hypotheses, although there are little to no data directly linking female orgasm or arousal with parturition. We describe specific ideas for further tests of the practice for parturition hypothesis, its practical implications, and the relevance of sex-birth interrelationships to informing ongoing debates concerning the evolutionary biology of female orgasm and sexuality more broadly. The practice for parturition hypothesis provides an organizing and testable framework through which to investigate potential benefits of female sexuality on birth.

Introduction

Sex and birth represent two major reproductive processes for women, and how they interact has practical considerations for women and healthcare providers as well as theoretical considerations for evolutionary scientists. There is much interest in how the process of birth impacts women’s postpartum sexual functioning (e.g., Martin et al., 2022), but comparably little research explores how women’s pre-parturition sexual function and sexual activity may affect birth outcomes. Given the difficult nature of human childbirth (Dunsworth & Eccleston, 2015), this is an important question. Here, we develop and evaluate a new theoretical framework, called “practice for parturition,” which proposes that sexual activity provides opportunities for women’s bodies and minds to physically and psychologically prepare for the novel challenge of childbirth.

First, we briefly review a pioneering body of work regarding sex-birth interrelationships by the late reproductive biologist, Niles Newton, whose studies motivated the present work. Second, we introduce the practice for parturition framework, which we consider an extension, application, and partial evaluation of Newton’s ideas. Third, we review the physical aspects of practice for parturition, detailing how the female genito-pelvis accommodates sex and birth via voluntary and involuntary mechanisms. Fourth, we review the psychological aspects of practice for parturition, describing similarities between birth psychology and psychological states contributing to sexual pleasure in women, suggesting that relinquishment of cognitive control jointly supports sexual function and unimpeded birth. Fifth, we evaluate the practice for parturition framework through three systematic literature reviews, evaluating the following predictions: (1) Overlapping pelvic floor interventions will demonstrate positive effects on female sexual function as well as birth outcomes; (2) the presence of sexual activity and sexual function prior to birth will predict improved birth outcomes; and (3) the presence of sexual dysfunction will predict poorer birth outcomes. Finally, we discuss the evolutionary and practical significance of the practice for parturition hypothesis, offering recommendations for further testing while considering sociocultural influences upon sex-birth interrelationships.

Throughout this article, we use the words “woman” and “women” to refer to adult human females, the singular sex class of humans capable of conceiving, gestating, and giving birth. We use the phrase “sexual function” to describe the capacity of females to experience desire, arousal, lubrication, orgasm, and sexual satisfaction during sexual activity. We use the phrase “sexual activity” to encompass diverse forms of sex, including masturbation, digital and oral sex, and intercourse, enjoyed in solitary or in partnered, homosexual or heterosexual, contexts.

Sex-Birth Interrelationships

Newton (1923–1993) was a prolific scientist and popular writer as well as a wife and mother of four children (Martucci, 2018).1 She studied and wrote about female reproductive biology and women’s well-being during a period of rapid expansion in sex research, marked by increasing cultural acceptance and softening of taboos concerning sexuality more broadly. Newton applied comparative and qualitative approaches to investigate interactions among menstruation, lactation, parturition, emotions, sexuality, and relationships. One of Newton’s (1955, 1973) key contributions was describing interrelationships among coitus, birth, and breastfeeding in women (Fig. 1). She characterized these three processes as highly sensitive to environmental context, stimulatory of care-taking behavior, and involving large quantities of central oxytocin release.

Fig. 1.

Overview of phenotypic similarities among and spillover between sex, birth, and lactation in women, based on Newton’s work on sex-birth-lactation interrelationships

Importantly, as part of this work, Newton (1973) described a set of bodily, emotional, and sensory similarities of sexual arousal and orgasm with natural, undisturbed labor and birth, proposing that these sex-birth overlaps reflect shared psychophysiological mechanisms (Table 1). Newton also proposed that inhibition or dysfunction of one reproductive process could interfere with other interconnected, reproductive processes. Such “borrowing” of mechanisms from one process for another is a frequently observed phenomenon in evolutionary biology; a relevant example is the overlapping endocrinological and physiological mechanisms between menstruation and parturition, with certain parturition complications being traceable to pre-existing, aberrant menstruation (Pavlicev & Norwitz, 2018). Despite Newton’s insights, effects of female sexual function and activity on subsequent parturition have generally been studied in very narrow contexts, such as whether or not intercourse induces labor (e.g., Carbone et al., 2019). Furthermore, Newton’s sex-birth research has yet to be integrated into ongoing debates concerning the adaptive significance of female orgasm despite its potential relevance. If female sexual phenotypes, including but not limited to orgasm, provide measurable benefits to the difficult human birth process, then selection on these phenotypes should be occurring and the context of birth might be considered a shaper of female sexuality alongside male–female mating dynamics. Below, we extend Newton’s work by describing how physical and psychological mechanisms shared between sex and birth, including genito-pelvic reflexes and reduced cognitive control, might help to explain links between pre-birth sexual activity and subsequent parturition.

Table 1.

Phenotypic similarities between sexual arousal and orgasm with un-drugged, undisturbed childbirth [adapted from Newton, 1973]

Characteristic	Sexual arousal and orgasm	Undisturbed parturition
Breathing	Breathing quickens and deepens during arousal	Deep breaths during 1st stage of labor
	Interrupted breathing as orgasm approaches	Deep breaths with breath holding during 2nd stage of labor
Facial expressions	Facial expression indicating strain	Facial expression at 2nd stage of labor indicates great strain
Uterine activity	Rhythmic uterine contractions	Rhythmic contractions of uterus intensify as labor progresses
Cervical activity	Cervical secretions may occur	Cervical mucus plug loosening is one sign of labor onset
Abdominal activity	Periodical contractions	Periodical contractions and urge to bear down during 2nd stage of labor
Bodily activity	Strength and flexibility evident during coitus	Unusual strength and body expansion required to birth baby
Psychological and emotional responses	Inhibitions are often released during intercourse	Uninhibited during parturition, especially as baby descends
	Well-being follows orgasm	Joy and ecstasy follows baby’s emergence
Sensory perception	Whole body when sexually aroused becomes less sensitive to pain	Vulva becomes insensitive to sensation such that woman may be unaware of crowning
	Reduced sensory perception as orgasm approaches	Reduced environmental awareness as birth approaches

Practice for Parturition

The practice for parturition framework proposes that sexual activity provides opportunities for women to prepare for the demanding task of childbirth (Fig. 2). Such practice for parturition is predicted to occur via physical and psychological pathways, such that female sexual activity: (1) enhances awareness and maintains functionality of pelvic floor tissues, muscles, and reflexes through regular and varied use and (2) familiarizes women with the psychological experience of 'relinquishing' control over a largely automatic bodily process. Below, we outline in detail the physical and psychological pathways through which benefits of sex on birth are predicted to occur.

Fig. 2.

Overview of the practice for parturition framework

Physical Mechanisms Linking Sex and Birth

Sexual activity and parturition engage the same genital and pelvic structures. How might sexual stimulation of female genitalia and pelvic anatomy impact the ability of a woman’s body to cope with the physical demands of labor and birth? Indeed, during parturition, the vaginal canal and pelvic musculature experience an extreme degree of stretch and pressure unparalleled by any other body part (Ashton-Miller & DeLancey, 2009). The practice for parturition framework predicts that diverse forms of sexual activity and stimulation benefit later birth through contributing to the maintenance and healthy functioning of involuntary and voluntary aspects of genito-pelvic activity. A suite of mechanisms is involved.

Involuntary Aspects of Female Genito-Pelvic Function

Reflexes are fast, involuntary movements caused by a specific stimulus. A genito-pelvic reflex occurs when stimulation or pressure of a specific genital or pelvic region elicits automatic contractions in another genital or pelvic region (Levin, 2002). Sexual stimulation elicits automatic reflex activity throughout the genitals and pelvic floor; females have at least six known genito-pelvic reflexes in comparison to one in males (Levin & Edge, 2007). In women, genito-pelvic reflexes appear to play important roles in coitus as well as conception, but their functions are not fully understood, due to their complexity, the methodological challenges involved in studying them, and relatively little research attention (Spoelstra et al., 2018).

Given the multi-purpose nature of the vagina, it is logical to consider if and how these reflexes also function during labor and birth. Birth-related reflexes have received some research attention, but mostly in animals (for ethical and methodological reasons) and largely in separation from the literature on female sexuality.

Both Newton (1987) and Odent (1987) characterized a fetus ejection reflex, but the two researchers used the term to describe different phases of parturition. The “Newton” fetus ejection reflex is closely related to the well-known Ferguson reflex, which is initiated when the fetus descends upon the cervix in early labor, eliciting central oxytocin release via the actions of sensory neurons that respond to mechanical stretch of the cervix. As oxytocin levels increase, uterine contractility intensifies, which further increases the pressure of the fetal head upon the cervix, thus continuing the cycle via positive feedback (Ferguson, 1941). Newton’s specific and valuable contribution to our understanding of the Ferguson reflex was experimentally demonstrating that fear and unfamiliar environments reduce maternal oxytocin levels in laboring mice, inhibiting the process of parturition (Newton et al., 1966).

The “Odent” fetus ejection reflex has been observed in women who gave birth in undisturbed environments, and it appears to overlap with a powerful, peristaltic wave described in rabbit parturition by Ferguson (Newton, 1987; Odent, 1987). As labor progresses and birth approaches, Odent (1987) observed that undisturbed women experience highly intense and involuntary contractions that powerfully and rapidly expel the fetus, in contrast to women who voluntarily push to expel the fetus.

Interestingly, computational models indicate that voluntary muscular contractions are less effective than involuntary smooth muscle activity at expelling a fetus, as pelvic floor muscle activation during parturition increases resistance for the descending fetus (Parente et al., 2010). Data from pregnant women supports this computational prediction, as Aran et al. (2012) reported that the strongest predictor of failed labor resulting in cesarean delivery was pelvic floor strength, based on maximum voluntary squeeze pressure. Taken together, these findings point toward an important—and poorly understood—role of automatic, reflexive activity in the female genito-pelvis during parturition.

In a comprehensive review on genito-pelvic reflexes, Levin (2003) proposed that frequent sexual activity enhances vaginal and pelvic floor structure and functionality through increasing blood and oxygen flow to the genitals while providing regular exercise for the complex musculature and reflexive activity of the female pelvic floor. Under the practice for parturition framework, we emphasize the importance of automatic, reflexive genito-pelvic activity during birth, and suggest, in accordance with Levin, that pre-birth sexual activity contributes to the functionality of these mechanisms.

Voluntary Aspects of Female Genito-Pelvic Function

Pelvic floor functionality is typically assessed on the basis of both muscular strength, measured by intensity and duration of voluntary contractions, and tone, measured by applying pressure to resting muscles and then assessing the muscle’s resistance (Haylen et al., 2010). Several studies indicate positive associations between sexual function and pelvic floor strength and tone in women (Rosenbaum, 2007).

Both Kegel (1952) and Graber and Kline-Graber (1979) found that women who regularly orgasm had stronger pubococcygeal muscles than non-orgasmic women, but another study found no effect of pelvic floor strength on self-reported orgasmic capacity (Gameiro et al., 2013). Martinez et al. (2014) found that stronger pelvic floor muscles predicted higher levels of desire, arousal, orgasm, lubrication, and sexual satisfaction in young nulliparous women.

Weak pelvic floors predicted sexual dysfunction in both pregnant and non-pregnant women in another study (Santos et al., 2017). Women’s self-reported sexual function scores were associated with pelvic floor strength in another study, such that weaker pelvic floor muscles predicted higher levels of sexual problems (Ozdemir et al., 2017). Similarly, a large retrospective study found that women with higher pelvic floor strength were less likely to report sexual dysfunction (Pasqualotto et al., 2022).

Overall, these studies indicate that pelvic floor strength contributes to sexual functioning, but the causal direction between these variables is not fully elucidated. For example, Sartori et al. (2021) found that women engaging in sexual intercourse and experiencing orgasms demonstrated stronger pelvic floors than abstinent and non-orgasmic women. Given the beneficial effects of frequent sexual activity on vaginal and pelvic floor functionality, a reciprocal relationship between sexual function and pelvic condition seems most plausible. Indeed, pelvic floor interventions appear to improve female sexual function, as well as parturition outcomes, which we review below.

Psychological Mechanisms Linking Sex and Birth

In addition to the physical interrelationships between sex and birth, these two reproductive processes also share psychological similarities. Newton (1973) drew a parallel between sexual arousal/orgasm and labor/birth in that psychological inhibitions or blockages can be released during both activities. Sex and parturition both involve psychological experiences that are qualitatively distinct from ‘normal’ or everyday modes of thinking and feeling; however, birth comprises a comparably more intense experience that cannot be controlled or stopped in the same manner as a consensual sexual activity. The practice for parturition framework predicts that regular sexual activity increases the accessibility of psychological states that facilitate birth (Fig. 3).

Fig. 3.

The capacity to relinquish cognitive control promotes sexual pleasure and appears to have positive effects on labor and birth. The dashed arrow represents our hypothesis that experiencing “relinquished” states in sexual contexts increases the accessibility of those states in parturition contexts

Relinquished Cognitive Control in Birth and Sex

When women face labor and childbirth, they are confronted with a novel and unpredictable challenge that cannot be cognitively solved, given the central role of automatic processes in parturition. Engagement of complex cognitive processes such as linguistic communication and self-reflection hinder the process of parturition by interfering with the ability to focus on the intense bodily task of giving birth (Odent, 2009). Odent’s summary of cognitive factors that inhibit birth come from his direct experience in observing numerous parturients, but we note that his conclusions have not been subject to systematic testing.

Distracting thoughts and mind-wandering during sexual activity tend to reduce sexual arousal and desire in women (Carvalho & Nobre, 2010), though the causal direction among these variables is not fully clear. The tendency of thought, language, and self-reflection to interfere with sexual arousal, orgasm, labor, and birth can be conceptualized as a tension and tradeoff between higher-order cognitive processes with evolutionarily older physiological processes. Thus, psychological states that facilitate sexual pleasure as well as parturition might be expected to centrally involve modes of thinking and feeling that promote uninhibited and automatic activity of the genito-pelvis.

The importance of permitting a bodily process to unfold is clearly observable in women’s sex and birth experiences, as descriptions of both activities involve the theme of “letting go” or “surrendering” (Birnbaum & Gillath, 2006; Parratt & Fahy, 2003). For example, during sex, women report a stronger psychological need to “let go” compared with men (Birnbaum & Gillath, 2006). Detailed, qualitative descriptions of pleasurable sex emphasize the role of presence and immersion within the sexual experience, in contrast to analyzing the experience (Ménard, 2007).

This tension between cognitive processes that underpin ‘normal’ behavior and bodily processes that unfold automatically is also evident in labor and birth contexts:

The process of “releasing the body” occurs spontaneously and progressively throughout labor, but it is easily disturbed and is not simple to achieve because such a total bodily release is necessary. These difficulties are related to the self-control that is necessary to function in the social world, yet which needs to be released entirely to give birth spontaneously and naturally. (Parratt & Fahy, 2003, p. 6)

Given the important role of genito-pelvic reflexive activity in sex and birth, and based on women’s accounts of the need to “let go” in these contexts, we suggest that the capacity to relinquish cognitive control jointly facilitates pleasurable sex, effective labor, and efficient birth.

Relinquishing of Cognitive Control, Mindfulness, and Sexual Functioning

The capacity to relinquish cognitive control via focused attention and reduced analytical or self-reflective thought has clear, positive associations with multiple aspects of female sexual response and behavior. There are multiple, overlapping psychological constructs that describe the capacity to relinquish cognitive control, including absorption, openness, self-forgetfulness, and mindfulness.

Trait absorption describes a person’s tendency to become deeply focused upon and immersed within an experience, such as a daydream, visual stimulus, task, or sensation (Jamieson, 2005). Absorption is frequently used as a proxy for the imaginative and sensory dimensions of the personality trait of openness to experience, which encompasses imagination, creativity, and interest in art (DeYoung et al., 2012).

Interestingly, Swartz (1994) hypothesized that absorption constitutes an obligatory pathway for high desire and sexual arousal in women but not for men. Several findings are consistent with this hypothesis. Openness to experience positively predicts multiple aspects of sexual functioning in women but not men, including sexual desire, sexual pleasure, and coital orgasm frequency (Birnbaum & Gillath, 2006; Costa et al., 2016; Harris et al., 2008). Similarly, creative self-forgetfulness, the tendency to become deeply involved in sensory and imaginary experiences, demonstrates positive associations with sexual desire, non-coital sex frequency, and desire for masturbation in women (Costa et al., 2016, 2018).

Positive associations between these interrelated traits and female sexual pleasure demonstrate that psychological facilitators of women’s sexual functioning specifically involve the release of cognitive control via increased focus and attention, lack of conscious thought, and immersion into a physical-sensory experience. Focus on physical-sensory experience, alongside present and non-judgmental awareness, are core aspects of mindfulness-based approaches. Several studies have explored mindfulness in the context of female sexuality. Sood et al. (2022) found that women with higher levels of trait mindfulness, reflecting mindful attention and awareness of sensation, reported better sexual function and lower rates of sexual dysfunction. A meta-analysis of studies assessing the effects of mindfulness-based therapies on sexual function in women concluded that such therapies significantly increase sexual desire and arousal, and modestly improve orgasm (Stephenson & Kerth, 2017). Overall, it appears that dispositional traits as well as interventions that promote sensory immersion and attentional presence enhance female sexual pleasure.

Cognitive Control, Mindfulness, and Parturition

Research into mindfulness and parturition has explored how mindful awareness affects subjective components and perceptions of women’s birth experiences (e.g., Hulsbosch et al., 2021) as well as objective parturition outcomes such as the need for interventions. For example, one study found that the intervention group of pregnant women who received mindfulness training composed of practicing present-moment awareness and letting go of control had a lower frequency of emergency cesarean sections than the control women who received perinatal education only (Leng et al., 2023). Another study found that birthing women applying mindfulness training opted for analgesic drugs at a lower frequency than women who did not do the training, though this difference only reached a trend level of significance (Duncan et al., 2017). In a third study, pregnant women receiving mindfulness training with a focus on cultivating attention to current experiences were less likely to choose cesarean sections, epidurals, and analgesia (Veringa-Skiba et al., 2022), suggesting that mindfulness training may have supported the physiological birth process in these women.

Under the practice for parturition hypothesis, we emphasize the importance of surrendering control over a largely automatic bodily process. However, other researchers have emphasized the importance of perceived control during childbirth, including control over one’s own behavior as well as control over other people involved in the birth (Green et al., 2003). We specify that in the context of practice for parturition, we are interested in how women relate to, resist, or support the birthing process of their own body. In a recent review of qualitative studies on women’s birth experiences, Downe et al. (2018) concluded that women recognize that birth involves “going with the flow,” but prefer to exert control when decisions for interventions are required. Existing research into trait absorption and mindfulness is consistent with positive effects of reduced cognitive control on sexual pleasure and parturition. Further testing of these ideas is needed, as described below.

Evaluating the Practice for Parturition Framework

We hypothesize that regular and varied sexual activity provides practice for women’s bodies and minds to prepare for later parturition through combining genito-pelvic exercise with states of reduced cognitive control. Below, we conduct a series of systematic literature reviews to test three specific hypotheses deduced from the practice for parturition framework, drawing from studies on pelvic floor interventions, female sexual activity, function, and dysfunction, and labor and birth outcomes.

Hypothesis 1

Similar forms of pelvic floor interventions, including genital and perineal massage, and pelvic floor contraction and relaxation exercises, improve female sexual function (desire, arousal, orgasm, and satisfaction) as well as birth outcomes in healthy, reproductive-aged women.

Hypothesis 2

Pre-birth sexual activity (masturbation, intercourse, digital or oral sex) and sexual function (desire, arousal, orgasm, and satisfaction) predicts improved labor and birth outcomes in women.

Hypothesis 3

Sexual dysfunction (e.g., vaginismus) has negative effects on labor and birth outcomes. Vaginismus is a type of female sexual dysfunction that involves involuntary contraction of pelvic floor muscles causing fear, pain, and difficulty or inability to have sexual intercourse (Baril et al., 2023).

Method

Hypothesis 1: Eligibility

We considered any peer-reviewed study that assessed sexual function (desire, arousal, orgasm, lubrication, and satisfaction) and/or birth outcomes (labor duration, birth injuries sustained, and interventions required) in healthy, reproductive-aged women following a well-described pelvic floor exercise or genito-pelvic massage regimen. If available, we included meta-analyses and excluded individual findings and studies that were encompassed in the meta-analyses.

We excluded studies in languages other than English or French, as well as studies that were inaccessible for download or library loan. We excluded studies that used interventions during pregnancy as a means to improve postpartum sexual function and studies sampling menopausal women or women with diseases or ailments (e.g., multiple sclerosis, obesity, incontinence, etc.), other than dyspareunia (pain during sex) or pelvic pain.

Search Strategy

We used the database PubMed to search for articles. Returned article titles and abstracts were screened by NL Dinsdale for eligibility. Relevant references from eligible studies, and articles citing eligible studies, were also assessed for eligibility. Search terms included: “pelvic floor” AND “sexual function”; “pelvic floor muscle training” AND parturition NOT postpartum. Refer to Fig. 4 for an overview of the search, screening, and inclusion process.

Fig. 4.

Flow chart diagram outlining study search and inclusion process for Hypothesis 1.

Adapted from Page et al., 2021

Hypothesis 2: Eligibility

We considered any peer-reviewed study that compared birth outcomes in women who reported different levels of sexual function (desire, arousal, orgasm, lubrication, satisfaction) or frequencies of sexual activity (masturbation, intercourse). The primary outcomes included labor duration, birth injuries sustained, and interventions required. Meta-analyses of the effects of sexual function or activity on labor and birth were also considered for inclusion. Narrative reviews, case studies, and commentaries were not included.

We excluded studies in languages other than English or French, as well as studies that were inaccessible for download or library loan. Studies assessing postpartum sexual intercourse or sexual function were excluded, as were studies including women with diseases or ailments (e.g., obesity, incontinence, pelvic floor dysfunction), with the exception of women with dyspareunia or sexual dysfunction with no clear medical/physical cause (defined as pain during sex or low sexual desire). Studies measuring labor onset/gestational age as the sole outcome were excluded. Numerous studies have analyzed whether intercourse induces labor; we are not exploring that here, but if the study assessed additional birth outcomes such as labor duration or interventions, we included those findings.

Search Strategy

We used the database PubMed to search for articles. Returned article titles and abstracts were screened by NL Dinsdale for eligibility. Relevant references from eligible studies and studies citing eligible studies were also screened for eligibility.

Search terms included: “female sexual function” AND parturition NOT postpartum; “sexual desire” AND parturition NOT postpartum; “sexual arousal” AND parturition NOT postpartum; “lubrication” AND parturition NOT postpartum; “orgasm” AND parturition; “masturbation’ AND parturition; “Sexual activity during pregnancy” and “sexual intercourse” AND parturition NOT postpartum. See Fig. 5 for an overview of the search, screening, and inclusion process.

Fig. 5.

Flow chart diagram outlining study search and inclusion process for Hypothesis 2.

Adapted from Page et al., 2021

Hypothesis 3: Eligibility

We considered any peer-reviewed comparative study, retrospective study, or meta-analysis that analyzed data on birth outcomes (labor duration, birth injuries sustained, and interventions required) in relationship to vaginismus. We excluded studies in languages other than English or French, as well as studies that were inaccessible for download or library loan. Narrative reviews and case studies were not included.

Search Strategy

We used the database PubMed to search for articles. Returned article titles and abstracts were screened by NL Dinsdale for eligibility. References from eligible studies, and articles citing eligible studies were also assessed for eligibility. Search terms included vaginismus AND parturition. Please see Fig. 6 for an overview of the search, screening, and inclusion process.

Fig. 6.

Flow chart diagram outlining study search and inclusion process for Hypothesis 3.

Adapted from Page et al., 2021

Results

Hypothesis 1: Effects of Pelvic Floor Interventions on Sexual Function and Parturition

The 13 eligible studies are summarized in Table 2. There is a high degree of variability in the types of interventions used in these studies. In some studies, pelvic, abdominal, and/or genital massage was performed by a physiotherapist or trained expert (e.g., Wurn et al., 2004; Ventegodt, 2006; Zoorob et al., 2015; da Silva et al., 2016). Overall, these expert-performed interventions were successful in improving sexual function and reducing pain in women during subsequent sexual activity, suggesting that skilled practitioners can effectively target genito-pelvic muscles, tissues, and/or reflexes. We did not find studies that used these expert-performed pelvic interventions with pregnant women, but under the practice for parturition framework, such interventions are expected to facilitate labor and birth. It is possible that some of these techniques could be unsafe to use during pregnancy.

Table 2.

Effects of pelvic floor interventions on female sexual function and/or labor and birth outcomes

Author	Year	Type of intervention	Study design	Sample	Effects on female sexual function	Effects on labor and birth outcomes
Wurn et al.	2004	Massage of abdomen and pelvis with directed body movements intended to release adhesions performed by physiotherapist	Compared female sexual function using FSFI* before and after 10 sessions over a variable timeframe (5 days to + 2 months)	23 women aged 25–43 years with pain during intercourse and difficulty reaching orgasm	Total self-reported FSFI score increased, pain levels decreased, and orgasm was reported as more frequent	NA
Ventegodt et al.	2006	Acupressure performed by a physician which involves slow touch of vagina and pelvis with time for emotions to arise and be felt during therapeutic process	Participants rated sexual problems before and after 4 sessions over an 8 week timeframe	18 women aged 22–30 years with pain during sex, low desire, and/or absent orgasm	Self-reported sexual ability increased by average of 1 point (5-point Likert scale). 56% of participants reported symptom improvement following intervention	NA
Du et al.	2015	Pelvic floor muscle training (PFMT) involving contraction and relaxation exercises	Meta-analysis of randomized or quasi-randomized controlled studies that assessed effects of pelvic floor muscle training on parturition outcomes	12 studies with a total of 2243 primigravidae from numerous countries (n = 1108 intervention; n = 1135 controls)	NA	PFMT during pregnancy predicted significantly briefer 1st stage (M = 28.3 min shorter) and 2nd stage (M = 10.4 min shorter) of labor. No significant differences in rate of instrumental or delivery, or perineal injury, between PFMT group and controls
Zoorob et al.	2015	Pelvic floor massage with intravaginal stretching performed by a physical therapist	Randomized comparative trial with women assigned to pelvic floor physical therapy for 6–10 1-h sessions or injections	29 sexually active women over 18 years of age with chronic pelvic pain (17 women in physical therapy; 12 women received injections)	Sexual pain was significantly reduced in whole group, with greater pain reduction in women receiving physical therapy	NA
Da Silva et al.	2016	Transvaginal massage using Thiele technique (massage from muscle origin to insertion with bearable pressure)	Nonrandomized clinical assay with women assessed for pain and sexual function before and after intervention (5 min massages once/week for 4 weeks)	18 sexually active, reproductive-aged women with dyspareunia	Women’s total FSFI scores significantly improved: pain was eliminated and domains of desire, arousal, lubrication, orgasm and satisfaction increased	NA
Pourkhiz et al.	2017	Pelvic floor muscle training (PFMT) involving contraction and relaxation exercises	Participants randomly assigned to PFMT or routine prenatal care to assess effects of PFMT on sexual function during pregnancy	84 nulliparous women with a singleton pregnancy, doing exercises from 17–20 weeks until late pregnancy	Overall sexual function as well as domains of arousal, desire, orgasm, and satisfaction (measured with FSFI) were significantly higher in exercise group compared to controls during followup in late pregnancy	NA
Schreiner et al.	2018	Perineal dilation, pelvic floor muscle training (PFMT), and perineal massage	Systematic review of RCTs to investigate effects of pelvic interventions on labor and birth outcomes	22 RCTs (perineal dilation, n = 3; PFMT, n = 3; perineal massage, n = 6). 11 RCTs assessed pelvic floor symptoms (not reviewed here)		Most studies found no effect of perineal dilation on perineal tearing. One PFMT & one perineal massage trial predicted briefer 2nd stage of labor. Mixed results concerning lacerations & instrumental deliveries in perineal massage studies
Sobhgol et al.	2020	Pelvic floor muscle training (PFMT) involving contraction & relaxation exercises	Systematic review and meta-analysis of randomized controlled and quasi-experimental studies investigating effects of PFMT on parturition outcomes	16 studies (n = 2829 pregnant women)	NA	PFMT associated with reduced duration of 2nd stage of labor (M = 21 min shorter) and reduced rate of severe perineal trauma. No difference in mode of delivery or instrumental birth rates between controls and PFMT
Cao et al.	2022	Perineal dilation with inflatable device, PFMT, and perineal massage	Systematic review and meta-analysis of studies investigating effects of PFMT on perineal trauma	21 randomized controlled trials (n = 4931)	NA	PFMT and perineal massage may increase rate of natural delivery; PFMT may reduce duration of 2nd stage labor
Chen et al.	2022	Perineal massage	Meta-analysis of studies comparing birth outcomes between women receiving perineal massage with women receiving standard prenatal care	16 studies including 6487 pregnant women in total (n = 3211 intervention; n = 3267 controls)	NA	Perineal massage significantly reduced incidence of severe perineal tears only
Gomes Lopes et al.	2022	PFMT involving contraction and relaxation exercises at variable frequencies	Meta-analysis of randomized controlled trials assessing effects of PFMT on perineal laceration	9 trials involving 1829 pregnant women	NA	No difference in rate of perineal laceration during vaginal delivery between controls and PFMT group
Sobhgol et al.	2022	PFMT involving strong contractions before and after downward pelvic pressure	Randomized controlled trial to assess effects of PFMT (exercises performed at home 3x/day from 20 weeks to end of pregnancy) on female sexual function and birth outcomes	200 nulliparous women randomized to intervention group. Final sample was 93 women in PFMT group and 96 controls	No difference in FSFI scores during pregnancy between controls and intervention group. Adherence to exercises was low (50%) in intervention group	Nonsignificant trend of fewer severe perineal injuries and fewer forceps deliveries but more vacuum deliveries in PFMT group compared to controls. 1st stage of labor in PFMT group was 46.4 min briefer than controls but this was not significant
Zhang et al.	2024	Pelvic floor muscle training (PFMT) involving contraction and relaxation exercises	Meta-analysis of randomized controlled trials assessing effects of PFMT on episiotomy and severe perineal laceration	30 RCTs involving 6691 pregnant women	NA	No effect of PFMT on episiotomy (n = 20 trials). PFMT predicted significantly reduced risk of having a third or fourth degree perineal tear (n = 11 trials)

*FSFI (Female Sexual Function Index; Rosen et al., 2000) is a widely used self-report questionnaire that assess various facets of sexual function in women, including pain, desire, arousal, orgasm, and lubrication

Pelvic floor muscle training performed at home demonstrated positive effects on some aspects of parturition. Specifically, pregnant women assigned to pelvic floor muscle training, broadly composed of contraction and relaxation exercises, experienced briefer periods of pushing (second stage of labor), which is important because extended pushing predicts higher risk of birth injury (Cheng et al., 2004). Some studies found that pregnant women doing pelvic floor muscle training also experienced faster cervical dilation (first stage of labor), reduced risk of severe perineal injury, and higher rates of vaginal delivery with reduced need for instrumental assistance. The effects of at-home pelvic floor muscle training on female sexual function was only assessed in one study returned in the review, which is surprising given the correlations between pelvic floor strength and sexual function reviewed above. In this particular study, pregnant women doing pelvic floor muscle training did not demonstrate any improvements in sexual function compared to pregnant women not assigned to pelvic floor muscle training, but adherence to the exercises was low and sexual function decreased in all women as pregnancy progressed (Sobhgol et al., 2022). The exercises, even with low adherence, did appear to modestly but not significantly reduce labor duration, severe perineal injury, and forceps delivery rate for women in the intervention group.

Perineal massage, used in pregnancy to prepare the vagina and perineum for extreme stretch during parturition, appears to reduce the risk of severe perineal injury. Such an intervention is typically reserved for pregnant women, but vaginal stretching did show benefits on sexual function through pain reduction in non-pregnant women with chronic pelvic pain (Zoorob et al., 2015).

Overall, pelvic floor interventions consisting of massage and exercises appear to improve aspects of sexual function and parturition in women, but there remain many unknowns. Positive impacts of pelvic floor training and genito-pelvic massage on sexual functioning and birth outcomes likely arise through several interacting processes: increased awareness of genito-pelvic sensations; increased stretch, elasticity, and motility of genito-pelvic tissue; and increased pelvic floor muscle strength and tone (Ferreira et al., 2015). How these various interventions affect reflexive genito-pelvic activity is largely unknown, but under the practice for parturition framework, we expect that interventions capable of improving reflexive genito-pelvic activity to facilitate labor and birth.

Hypothesis 2: Sexual Activity, Sexual Function, and Parturition Outcomes

The nine articles summarized in Table 3 reveal mixed evidence for effects of sexual intercourse during pregnancy on parturition outcomes. Four studies found no difference in vaginal versus cesarean delivery rate between sexually active and abstinent pregnant women. However, data from Cameroonian women across three studies found that the presence of sexual intercourse during pregnancy was associated with multiple improved aspects of parturition, including: higher incidence of normal labor and spontaneous delivery; reduced need for episiotomy, instrumental delivery, and cesarean delivery; lower dystocia rate; fewer perineal tears; and briefer second stage of labor (Table 3). Sexually active pregnant women from Ethiopia also demonstrated a briefer second stage of labor compared to abstaining pregnant women (Tsegaye et al., 2021). Importantly, in all four of these studies, participants were asked whether or not they engaged in sexual activity while pregnant and were then assigned to the appropriate group prior to delivery. It is thus possible that factors such as partner presence, relationship intimacy, or beliefs about sex and pregnancy influenced the decision to engage in sex and that these factors could independently affect the process of parturition. Further, one of the studies finding positive effects of late-term intercourse on birth outcomes stipulated that intercourse involved semen ejaculation into the vagina (Simo et al., 2020), so it is possible that semen exposure played a role in some of the birth outcomes, though another study with the same requirement did not find any group differences in cesarean delivery risk (Atrian et al., 2014). Most of the studies assessed sexual activity during late pregnancy, so how sexual activity in early pregnancy or prior to conception may affect parturition outcomes is currently unknown, but is expected to have positive effects on parturition. Overall, some of the evidence reviewed in Table 3 supports the practice for parturition hypothesis, though the precise psychological and physical pathways through which these birth benefits occur cannot be clarified with the existing data.

Table 3.

Associations of pre-birth coitus or orgasm with subsequent labor and birth outcomes

References	Methodology	Sample	Sexual variable	Relationship to parturition
Baxter (1974)	Retrospective interviews	54 primigravidae	Self-reported capacity to orgasm during intercourse	Pre-pregnancy coital orgasms predicted briefer 2nd stage of labor
Tan et al. (2006)	Prospective longitudinal	200 pregnant women	Pregnant women kept coital diaries from 36 weeks to time of labor onset	No significant relationship between frequency of intercourse and rate of cesarean delivery
Tan et al. (2009)	Randomized trial	209 pregnant women randomly assigned to ‘coitus-advised’ group or control group (no advice)	Women kept coital diaries and were assigned to coitus or no-coitus group based on diaries	No effect of coitus or orgasm on rate of cesarean versus vaginal delivery
Castro et al. (2014)	Randomized, controlled, non-blinded trial	63 pregnant women randomized to coitus group and 60 pregnant women to abstinence	Sexual intercourse at term two times per week	No effect of coitus on rate of cesarean versus vaginal delivery
Foumane et al. (2014)	Prospective cohort	72 sexually active and 72 abstaining pregnant women	Unprotected vaginal intercourse after 37 weeks of pregnancy	Sexually active women more likely to have normal labor*, fewer cesarean deliveries, 2nd stage of labor ≤ 30 min
Atrian et al. (2014)	Cross-sectional	120 women presenting to hospital in labor	Presence or absence of sexual intercourse and exposure to semen in last week of pregnancy	No effect of intercourse on type of vaginal or cesarean delivery
Essome et al. (2020)	Comparative cross-sectional	300 pregnant women (69% sexually active)	Presence/absence of unprotected sex during pregnancy	Sexually active women less likely to demonstrate perineal and cervical tearing
Simo et al. (2020)	Prospective cohort	186 sexually active and 240 abstaining primigravidae	3rd trimester intercourse at least once/week with ejaculation into vagina	Sexually active women had lower rate of dystocia**, fewer instrumental and cesarean deliveries, higher frequency of 1st stage of labor < 6 h and 2nd stage of labor < 30 min
Tsegaye et al. (2021)	Prospective cohort	283 women pregnant with singleton fetus	Information on characteristics that may impact 2nd stage of labor, including presence or absence of sexual intercourse in late pregnancy, were collected via interviews	Sexually active women were significantly less likely to demonstrate prolonged 2nd stage of labor (prolonged 2nd stage of labor > 100 min)

*Normal labor involves assessment of fetal heart rate, rate of cervical dilation, fetal head descent, and contractions; if dilation occurs too slowly and medical action is required, labor is no longer categorized as normal

**Dystocia occurs when a baby’s shoulder gets caught above the mother’s pubic bone

No studies assessed female sexual arousal or lubrication in relationship to parturition outcomes, and only two studies meeting our criteria assessed orgasm in association with parturition. Tan et al. (2009) found no difference in the rate of cesarean delivery between women self-reporting orgasms and women recording no orgasms in late pregnancy. Baxter (1974) found that a woman’s self-reported capacity to orgasm during intercourse (coital orgasm) prior to conception predicted a briefer mean second stage of labor (x̅ = 41 min) compared with women who reported no coital orgasms prior to conception (x̅ = 70 min). However, Baxter did not report the standard deviations of these data, precluding significance tests of group differences. Though this reduced duration of the second stage of labor has been criticized as clinically insignificant (Wagner & Pavličev, 2017), interventions and severe birth injuries appear to significantly increase in likelihood when the second stage of labor exceeds 60 min (Cheng et al., 2004). Baxter’s (1974) study is extremely methodologically limited, relying on self-report of sexual response at a much earlier time point: participant memory could be incorrect and self-report of sexual behavior is particularly vulnerable to bias.

Hypothesis 3: Sexual Dysfunction and Parturition Outcomes

These six studies are summarized in Table 4. Overall, women with vaginismus demonstrated higher rates of instrumental delivery, cesarean delivery, and perineal injury compared to unaffected women. Cesareans in affected women may occur by maternal request, or in response to delayed labor progress and inability to do other types of interventions that require vaginal penetration. Women with vaginismus are particularly vulnerable to perineal injury during birth, which is likely attributable to perineal hypertonia (Tourrilhes et al., 2019). Consistent with the logic of practice for parturition, Tourrilhes et al. (2019) suggested that sexual therapy could help pregnant women with vaginismus prepare for birth. Furthermore, Zulfikaroglu and Yarman (2022) found that rates of cesarean delivery did not differ between women without vaginismus and women who had received treatment for vaginismus.

Table 4.

Effects of vaginismus on women’s labor and birth outcomes

References	Type of Study	Sample	Parturition Outcomes
Drenth et al. (1996)	Retrospective questionnaire based study	28 pregnant women with vaginismus	High rate of instrumental delivery and cesarean section (~ 42%) in affected women relative to general population (30.3%)
Goldsmith (2009)	Population-based study	Women with (n = 118) and without vaginismus giving birth from 1988–2007 (n = 192 954 births) in Israel	Women with vaginismus had significantly higher rates of labor induction, instrumental delivery, and cesarean delivery
Moller et al. (2015)	Retrospective, population-based study	454 913 women giving birth during 2001–2009 in Sweden (2554, 0.6% with vaginismus)	Compared to unaffected women, women with vaginismus more likely to deliver via cesarean section (including by maternal request) or suffer perineal tear
Tourrilhes et al. (2019)	Retrospective multicenter study	19 women with vaginismus having first child between 2005 and 2015 in France	High rate of dystocia, perineal injury, cesarean and instrumental deliveries
Baril et al. (2023)	Retrospective cohort study	All women entering hospitals to birth from a National Inpatient Sample in USA (n = 13 792 544; 879 women with vaginismus)	Vaginismus associated with increased risk of cesarean delivery, instrumental delivery, and prolonged hospital stay
Zulfikaroglu and Yaman (2022)	Cross-sectional study	297 women with vaginismus who received treatment that worked	No difference in cesarean delivery rates between with treated vaginismus and general population

Consistent with the practice for parturition framework, the studies summarized in Table 4 indicate that vaginismus tends to negatively impact labor and birth progress through physical and psychological mechanisms. The link between sexual dysfunction and parturition problems may be attributable to dysfunctional genito-pelvic reflexes, the inability of affected women to relax their pelvic floor muscles and to allow their perineum to soften during labor, as well as the presence of fear and anxiety concerning the sensations of birth (Rosenbaum & Padoa, 2012).

Discussion

We have drawn from Newton’s work on sex-birth phenotypic interrelationships to forward the practice for parturition hypothesis, which proposes that sexual activity benefits later parturition through physical and psychological pathways that overlap between sex and birth. There is relatively little research into the effects of female sexual activity, function, and dysfunction on subsequent parturition; such sex-birth connections have practical implications for pregnant women, and theoretical implications for understanding selective pressures on female sexuality more broadly.

Our review of genito-pelvic reflexes and psychological states characterized by reduced cognitive control provides a starting point to further study mechanisms shared between sex and birth. If sexual activity improves parturition through the mediating variable of genito-pelvic functionality, then the interventions most resembling natural sexual activity, or those interventions producing similar benefits to natural sexual activity, should be of most benefit to birthing women. The interventions reviewed in Table 2 are delivered or performed in nonsexual contexts, but they do involve some forms of stimulation that broadly overlap with various types of sexual stimulation, such as stretch of tissue and contraction of pelvic muscles.

Future studies might further address these unknowns by comparing birth outcomes among pregnant women randomly assigned to the following conditions: sexual activity; sexual activity plus pelvic floor muscle training (or expert-performed genito-pelvic massage); abstinence; and abstinence plus pelvic floor muscle training (or expert-performed genito-pelvic massage). Such comparisons might help disentangle contributions of sex-specific genito-pelvic maintenance from the effects of different forms of pelvic floor interventions. Interestingly, in a study on postpartum sexual function, Bhat and Shastry (2022) found that women doing pelvic floor muscle training plus regularly engaging in sexual activity with orgasm showed higher improvements in postpartum sexual function than women doing pelvic floor muscle training alone. Notably, women in the pelvic training plus orgasm group were better at relaxing their pelvic floor muscles than women in the pelvic training only group. Under the current framework, these results could be considered in the context of birth preparation, given the importance of genito-pelvic relaxation for fetal descent and birth. Thus, a similar study with pregnant women would be useful to test the practice for parturition framework.

Under the practice for parturition hypothesis, we suggest that psychological states supporting sexual pleasure reinforce the availability of those states during labor and birth. One approach might involve conducting detailed interviews that can assess the depth of sexual pleasure and sensory awareness a woman experiences during sex, and whether those experiences predict subjective psychological experiences during birth, as well as objective labor and birth outcomes.

The systematic literature reviews provide preliminary support for practice for parturition, but there are many gaps in existing data. A small set of studies indicate that sexual intercourse during pregnancy may improve labor and birth, but these findings require replication and extension in diverse female populations. Sexually active, pregnant women in our reviews were partnered with men; future studies could investigate how the sexual activity and function of women in same-sex relationships, or how solitary sexual activity of unpartnered or abstinent women, impact labor and birth. Furthermore, we found no data investigating the effects of preconception sexual activity and sexual function on parturition outcomes, with the exception of Baxter’s (1974) work on orgasm that was subject to significant limitations. Collecting data on female desire, arousal, and orgasm prior to, and during pregnancy, and connecting these phases of female sexual response to parturition outcomes should provide key insights for further understanding sex-birth interrelationships. Other types of useful data might involve objective assessments of sexual and genito-pelvic function, such as reflex activity, tissue engorgement, or lubrication. Under practice for parturition, any forms of sexual activities that engage the genito-pelvis and involve psychological states of reduced control are expected to have beneficial effects on the birth process. Finally, willingness to engage in intercourse during pregnancy may reflect other variables that also independently influence parturition, such as partner presence, relationship health, partner support, medical conditions, personality characteristics, and cultural teachings.

Practice for parturition bears directly on evolutionary research into the adaptive significance of female orgasm, in that it posits advantages to female sexual phenotypes that facilitate childbirth. Evolutionary research has focused on explaining female orgasm, but orgasm is only one component of female sexuality, and examining it in isolation results in an incomplete understanding of female sexuality. Indeed, Newton (1955) was critical of research approaches to female biology that artificially separated sexual processes from reproductive processes, as she perceived these processes as inexorably linked, partially through pleasure and positive emotions that reinforce intercourse, reproduction, and mothering. To more deeply understand the evolutionary factors shaping female sexuality, co-occurring psychological and physiological phenotypes present in interrelated reproductive contexts need to be examined (e.g., Fig. 1)—especially those characteristics of female sexuality that appear to involve sex-specific elaboration (Wheatley & Puts, 2015), such as prolonged sexual arousal and the capacity for highly expressed orgasm phenotypes. Levin’s (2002, 2003, 2015, 2020) extensive body of work clearly demonstrates that women can experience prolonged periods of sexual arousal and that female sexual arousal creates numerous changes in the female reproductive tract, some of which are related to conception and occurring whether orgasm takes place or not. Given women’s capacity for prolonged sexual arousal, the effects of arousal-induced changes need to be more deeply understood, as they may facilitate reproductive processes other than conception, such as birth, through maintaining the elasticity and functionality of genito-pelvic tissues and reflexes.

Furthermore, features of female orgasm, and female sexuality more broadly, that are salient to an adaptive account, such as psychological elicitors of desire and arousal as reviewed above (e.g., absorption as described by Swartz, 1994), sexual intercourse during non-conceptive windows such as pregnancy, the absence of a post-orgasm refractory period (Levin, 2009), and the capacity for different kinds of long-lasting and multiple orgasms generated from numerous genital and bodily sites (Levin, 2015; Sayin, 2012)—which could be related to women’s more numerous genito-pelvic reflexes—have yet to be integrated into an evolutionary framework. Understanding the adaptive significance of female sexuality can usefully proceed in the context of specific hypotheses such as the practice for parturition framework described here.

An evolutionary approach thus focuses on the adaptive significance of women's sexuality, with benefits of sexual behavior and pleasure to health and reproduction in the context of childbirth, as reviewed systematically here. These benefits have their biological bases in the physiological and psychological links of sexuality with childbirth, as originally described by Newton. Such evolutionary and biological perspectives and processes must also be considered alongside socially and culturally constructed norms (society-specific influences that structure cognition, beliefs, and behavior), given that the adoption of local norms is expected to represent a generally adaptive mechanism of enculturation (Bolin et al., 2021). Women’s sexual functioning and childbirth outcomes will thus, as for any behavioral and social trait, vary among cultures, and depend upon how individual women embody and express the sexual and reproductive mores and expectations specific to any given society (Tolman & Chmielewski, 2019; Velotta & Schwartz, 2019).

In this general context, society-specific cognitive and affective development generates mental representations that aid in navigating the demands and challenges specific to any given situation, that are usefully referred to as psychological mindsets (Gollwitzer et al., 1990). With regard to parturition, mindsets can vary from “natural” (considering an optimal childbirth as an organic process occurring at home, without medical intervention), to “medical” (considering childbirth as a clinical process best suited to the hospital environment), with the adoption of any given mindset being affected by a woman's upbringing, social pressures, and mass-media depictions (Hoffman & Banse, 2021; Hoffman et al., 2023). With regard to women's sexuality and sexual pleasure, mindsets also vary in the context of cultural influences and norms (Huberman et al., 2021), including for example self-developed views that sensuality and individual gratification are healthy and normal, to ideas based on internalization of gendered scripts, that define how women 'ought' to behave and feel sexually in relation to their partner (Mueller et al., 2016; Seabrook et al., 2016; Simon & Gagnon, 1986).

Mindsets may, in principle, also connect sexuality with childbirth, thus representing psychological mechanisms with effects in both domains. Depending upon sociocultural context, any particular mindset could thereby potentially enhance experiences (such as beliefs in women's bodies, sexual pleasure, and childbirth as “natural” or trustworthy; e.g., Dixon et al., 2024), or, alternatively, lead to discordance (such as beliefs that women's sexuality is intended predominantly to please heterosexual partners, which could interfere with reproductive functioning) (e.g., Scappini & Fioravanti, 2022). Future research addressing connections between female sexual function and parturition must consider multiple possible explanations, such as cognitive and cultural components like mindsets, in addition to evolutionary and biological ones, as we have explored above in the context of the hypothesis of practice for parturition.

The practice for parturition hypothesis provides a practical extension of Newton’s pioneering work while bridging the sexuality and obstetrics literatures. With further testing, the hypothesis could potentially inform healthcare practitioners who support women during multiple phases of reproductive life, and in the vision of Newton, guide scientists toward a greater knowledge of, and appreciation for, the diverse and elaborate nature of female sexuality.

Author’s Contributions

NL Dinsdale: Project development, literature review, manuscript writing. BJ Crespi: Project development, editing.

Funding

This project was funded by an NSERC CGS D grant awarded to Natalie L. Dinsdale.

Availability of data and materials

Not applicable.

Code availability

Not applicable.

Declarations

Conflict of interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.