Back to Basics

‘Developments in, and increasing access to, assisted reproductive technology (ART) options has allowed opportunities for biological parenting for a multitude.’

The field of reproductive endocrinology and infertility has made massive advancements in the recent past in terms of offering comprehensive fertility care to individuals seeking to start or expand their families. Developments in, and increasing access to, assisted reproductive technology (ART) options has allowed opportunities for biological parenting for a multitude. Technological improvements in the field of cryopreservation have contributed to an increasing consideration of embryo, and now oocyte, cryopreservation as “procreative banking” strategies. The past decade has witnessed a meteoric expansion in technological options for genetic analysis of embryos, allowing to a certain extent, mitigation of aneuploidy-related pregnancy wastage on one hand, and enhancing the likelihood of conceiving a healthy child free of inherited disorders, on the other. Despite such innovative progress in the infertility arena, success rates for ART have remained stagnant for over a decade, with per cycle pregnancy rates of 42-48% for young women undergoing fresh autologous embryo transfer.¹ While remaining the most successful and increasingly used treatment to overcome infertility, access to ART is far from equitable^2,3; personal perspectives, financial constraints, and service access are some of the challenges that limit utilization of effective fertility treatment options among communities. It is no surprise that women, couples, and providers have more than ever begun to question, “What can we do to improve natural fertility?”

It is rare to meet a couple seeking fertility treatment who has not already scoured the Internet or elicited the advice of family and friends searching for natural methods of boosting his or her fertility potential. Nutritional supplements, specialized diets, relaxation exercises, and even certain sexual positions are commonly passed on as ways to boost odds of conceiving. Individuals who are frustrated after months or years of failed attempts to conceive are eager to take on these lifestyle adjustments in hopes they will tip the scale in favor of pregnancy. Unfortunately, this often results in more stress and aggravation when alas they find themselves at their first infertility consultation discussing “unnatural” methods of conception such as intrauterine insemination and ART.

In this issue of American Journal of Lifestyle Medicine, Rossi et al examine multiple modifiable lifestyle habits that may impact fertility. The authors rightfully point out that the most influential factors impacting fertility are in fact nonmodifiable. It has conclusively been demonstrated that female age is the largest contributor to fecundability and the single best predictor of fertility treatment success.⁴ Other fixed variables affecting fertility, such as genetic makeup and congenital anomalies, are out of the hands of the individual seeking pregnancy.

Diet modification is often considered early in the process of attempting to conceive as a strategy for naturally improving fertility. A “fertility diet” consisting of higher intake of monounsaturated fats, low-glycemic carbohydrates, and less reliance on animal protein is described by Chavarro et al⁵ who demonstrated a 66% lower risk of ovulatory disorder infertility (95% confidence interval = 52% to 77%) and 27% lower risk of infertility due to other causes (95% confidence interval = 5% to 43%) in women in the highest tier of diet adherence. Notably, statistical significance was maintained when controlling for female age and body mass index (BMI). In addition to diet, antioxidants and other supplements are commonly advertised to enhance fertility, albeit with inconsistent results, and a recent meta-analysis failed to support such claims.⁶ On top of diet and supplements, caffeine and alcohol consumption have been scrutinized as contributors to subfertility. While a retrospective study demonstrated caffeine intake to be related to a higher risk of subfertility,⁷ a recent larger prospective study did not corroborate such findings.⁸ Evidence supporting a negative impact of alcohol on fertility is likewise conflicting.^9,10

More well-established relationships exist between BMI, tobacco use, and infertility. Having a low (<20 kg/m²) or high (>24 kg/m²) BMI is suggested to have detrimental effects on fertility,¹¹ largely attributable to a higher incidence of anovulation in these BMI categories. An accruing body of ART data identifies adverse implications of female obesity for egg quality, and of male obesity for sperm parameters.¹²Cigarette smoking also negatively affects fertility via nicotine-induced compromised folliculogenesis and altered meiotic spindle function in gametes.¹³ Additionally, ART outcomes are compromised in smokers. Acceleration in processes of ovarian senescence is described in the setting of chronic tobacco exposure and age at menopause can to be accelerated by several years in smokers. With 18% of Americans smoking and more than one third of Americans being obese,^14,15 the incidence of infertility related to these lifestyle choices is not to be discounted.

Of utmost importance is the realization that studies evaluating lifestyle factors such as those described above are innately flawed by bias and inability to properly conduct randomized control trials in the infertile population. Though logically plausible that influences such as alcohol and caffeine intake may alter fertility potential, it cannot be overlooked that other lifestyle choices that often go hand in hand with these habits may also contribute to one’s ability to conceive and thus a cause and effect relationship will be difficult, if not impossible to establish.Stress is an unavoidable consequence of infertility. Sentiments of inadequacy and hopelessness are ever-present in individuals who have failed to conceive with or without fertility treatment, only further augmenting the levels of anxiety that one suffers when confronted with this diagnosis. Stress itself has been linked to decreased fecundability.¹⁶ Fortunately, the negative impact of stress and depression on fertility may be mitigated with cognitive–behavioral therapy and support group participation,¹⁷ highlighting the importance of a multidisciplinary approach to treatment of the infertile patient.

Thus, while Rossi et al have provided an impressive summary of modifiable lifestyle choices potentially affeting fertility, do we as health care providers for women and couples, during one of the most trying times of their lives, want to layer on added stress by instructing our patients to adhere to stringent diets, embark on a strict exercise regimen, and restrict some of the simple pleasures, such as a morning latte, in order to gain modest if any added benefit for a successful pregnancy? A realistic and tangible approach is to aim for consistency in offering comprehensive counseling regarding overall health benefits of (a) achieving and maintaining a normal body weight through a combination of regular physical activity and attention to dietary caloric and portion control, (b) limiting known toxic exposures such as nicotine, and (c) encouraging infertile couples to take a proactive stance at destressing while engaging in pleasurable activities. Endorsing a healthy lifestyle for general well-being rather than for optimization of conception would seem to be a more realistic approach that provides the patient with attainable goals to boost self-esteem in a time of physical and emotional vulnerability.