Table 1.

Summary of data from all included studies

Author, year, country	Aim of the study, study design, sample size	Participant characteristics	Intervention characteristics	Control group characteristics	Key findings reported by author (s)
Hilal Yuksel, 2017, Turkey [35]	To determine whether breathing exercises for pregnant women during the second stage of labour have beneficial effects on maternal pain, duration of labour, and the first-minute, APGAR scores, RCT 250 (IG-125, CG-125)	Nulliparous pregnant women in the second stage of labour with a gestational age ranging between 37 and 42 weeks. Those using analgesics or anaesthetics, and those with clinical instability, psychiatric disorders and the inability to cooperate with breathing exercises were excluded.	The main components of breathing exercises during training were: First, fill your stomach and then your lungs with air while breathing in. Feel the expansion in the stomach. Make sure the muscles from your stomach to your knee are relaxed, as if you are urinating while breathing out. When there is pain, perform deep abdominal breathing exercises, and take a deep breath in and hold as much as you can. Try to push the baby downward. You can do it by holding your breath or breathing out quite slowly from your mouth. The most important point in this stage is that you should not fill up the stomach with air, and you should push downward to deliver the baby. You should continue the pushing until the pain is relieved.	Standard care	The perception of the pain and duration of the second stage of labour was lower in the interventional group (369.6 ± 92) seconds as compared to the control group (440.7 ± 142.5) seconds, (P < 0.001). The mean first-minute APGAR scores were higher in the intervention group (8.84 ± 0.50) as compared to the control group (8.73 ± 0.89), (P > 0.05).
Lisa Kane Low, 2013, USA [33]	To test the effect of spontaneous pushing (either with or without prenatal perineal massage) compared with directed pushing on incontinence outcomes in women evaluated one year after their first birth. RCT (Solomon four group design), 249 (G1-39, G2-34, G3-32, G4-40).	Participants were pregnant women who are at least 18 years of age, no history of genitourinary pathology, continent during first 20 weeks of pregnancy by self-report, and continent at 20 weeks gestation by negative standing stress test. Women with demonstrable stress incontinence were excluded.	Group 1: directed pushing, or coached pushing using a closed glottis Valsalva maneuver. Group 2: prenatal perineal massage initiated in the third trimester with a standardized training regarding its use and then directed pushing during second-stage labour. Group 4: combination of group 2 and 3 treatment, with spontaneous pushing plus perineal massage.	Group 3: spontaneous pushing, with instruction provided prenatally via a standardized training video. This method included instructing the woman to follow her bodily sensations and push as she felt the urge.	The duration of second stage of labour in minutes was lower in Group 4 (spontaneous pushing and perineal massage) as compared to other groups. However, the results were not statistically significant (G1-131.12 ± 91.08, G2-130.28 ± 126.67, G3-151.69 ± 133.26, G4-104.19 ± 88.08, P = 0.47). Spontaneous pushing did not reduce the incidence of postpartum incontinence experienced by women one year after their first birth.
Sevil Cicek, 2017, Turkey [36]	To assess the effects of breathing techniques training on anxiety levels of pregnant women and the duration of labour. RCT, 70 (IG-35, CG-35).	Participants consisted of nulliparous women aged 18-35 years, 38-42 weeks pregnant with a single healthy foetus in vertex position, and expected to have spontaneous vaginal delivery without any pregnancy complications and in the early latent phase of labour (0-1 cm).	The four stages of breathing in the Lamaze breathing model were taught. In the latent phase (0-4cm) slowly inhale through nose and exhale through mouth. Then inhale through nose to a count of five seconds and exhale through mouth with the same slow way in five seconds. In the active phase (4-8 cm) breathe without using abdominal muscles with upper lungs. Accelerate and lighten your breathing as the contraction increases in intensity. Breathe in and out rapidly through mouth. In the transition phase (8-10 cm) breathe in and out through mouth. Blowing should be rapid and shallow.	Routine care	There were significant differences between the two groups regarding the mean State Anxiety Inventory (SAI) at late active phase of labour (P < 0.001). There were significant differences between the two groups regarding and the mean duration of first stage of labour (P < 0.001). The X ± SD of the duration of second stage of labour was (19.11 ± 12.49) minutes and (24.48 ± 16.32) minutes in the experimental and control group respectively with (P = 0.135).
Steven L Bloom, 2006, USA [34]	To compare obstetrical outcomes associated with coached vs uncoached pushing during the second stage of labour. RCT, 20 (IG-163, CG-157).	Participants were those with a singleton foetus in cephalic presentation and regular uterine contractions with cervical dilatation of at least four cm. Women with a prior history of urinary incontinence, anal incontinence, pelvic organ prolapse, any known complication of pregnancy, or an estimated foetal weight greater than 4000 g were excluded.	Step 1: head of bed up 30 degrees. Step 2: position patient, as she desires, on her back or either side. Step 3: coach patient to pull back on both knees and tuck her chin while the provider or partner supports the legs. Step 4: coach the patient to take a deep breath and hold during the peak of a contraction then bear down and push for 10 seconds; repeat this as long as the contraction continues.	Step 1: head of bed up 30 degrees. Step 2: position patient, as she desires, on her back or either side. Step 3: the patient should be told simply to “do what comes naturally” or whatever the patient feels the urge to do while in bed.	The second stage of labour was abbreviated by approximately 13 minutes in coached women (IG-46.3 ± 41.5, CG-59.1 ± 49.1, P = 0.014). There were no other clinically significant immediate maternal or neonatal outcomes between the two groups.
A Boaviagem, 2017, Brazil [37]	To assess the efficacy of the breathing patterns during the active phase of the first stage of labour for maternal anxiety. RCT, 140 (IG-67, CG-73).	Participants were parturient in active labour, aged 12-40 years, with gestational age between 37 and 41 weeks. Those with multiple pregnancies, pregnancy with a dead foetus, analgesic use, clinical instability and psychiatric disorders were excluded from the study.	The patient was instructed to inhale slowly, count from one to five and breathe out gradually, counting from five to one. For the breathing pattern with post exhalation pause, the patient was instructed to take a deep breath and increase the post-exhalation pause (one-two seconds). With respect to expiratory deceleration, the patient was instructed to take an extended exhalation, propelling the lips forward (pursed lip breathing).	Routine care	There was no difference between groups two hours after the first evaluation regarding to anxiety (MD = 0.3 (95% CI = -4.2, 4.8)), pain (MD = 0.0 (95% CI = -0.8, 0.7)), fatigue (MD = -0.5 (95% CI = -1.4, 2.5)) and maternal satisfaction (MD = 0.9 (95% CI = -0.1, 2.0). The labour duration measured in hours, found that the duration in intervention group was 7.73 ± 3.22 and control group was 8.02 ± 2.52, showing a significant difference, with a mean of 0.28 (95% CI = 1.32-0.75).
Sushmitha R Karkada, 2022, India [38]	To explore the impact of antepartum breathing exercises on maternal outcomes of labour among primigravida women. RCT, 261 (IG-138, CG-123).	Women were eligible to enter the trial if they had a singleton pregnancy with a cephalic presentation, had low risk (no pre-existing medical complications or existing obstetric complications), and were first-time childbearing women (primigravida). Women were excluded from entering the trial if they had pre-identified risk factors like eclampsia, preterm labour, placenta previa, multiple gestation, malpresentation and malposition or had been previously randomized to the trial.	Five breathing patterns were introduced namely- cleansing breathing for relaxation, slow-paced breathing, modified-paced breathing and patterned-paced breathing. Breathing patterns were demonstrated by the investigator to the women on a one-to-one basis. Women were asked to repeat these breathing patterns immediately after teaching and were advised to practice them twice daily for 15 minutes. Instructions were given to continue during the active phase of the first stage of labour under the supervision of labour room nurses.	The women randomized to the standard care group received health talk on antepartum care and services according to local health care provision.	A total of 98 (70%) primigravida women who practised antepartum breathing exercises had spontaneous onset of labour. The odds of spontaneous onset of labour after randomization in the intervention group was 2.192 times more when compared to standard care at a (95% CI = 1.31-3.36, P < 0.001). The requirement for augmentation of labour was minimal and there was a reduction in the rate of caesarean deliveries (P < 0.05) based on the χ2 test. A statistically and clinically significant difference was found in the mean duration of labour (in hours) between intervention 5.5127 (SD = 1.998) hours and standard care group 7.238 ± 3.678 h, resulting in a mean of 132 minutes, P < 0.001.
J I Schaffer, 2005, USA [30]	To determine effects of coached vs uncoached maternal pushing during the second stage of labour on postpartum pelvic floor structure and function, RCT, 128 (IG-67, CG-61).	Nulliparous women in spontaneous active labour with uncomplicated pregnancies between 36 and 41 weeks gestation, has regular uterine contractions, cervical dilatation of at least four cm, and foetuses in cephalic presentation. Women with a previous history of urinary incontinence, anal incontinence, pelvic organ prolapse, any known complication of pregnancy, or an estimated foetal weight greater than 4000 g were excluded.	Step 1: head of bed up 30 degrees. Step 2: position patient, as she desires, on her back or either side. Step 3: coach patient to pull back on both knees and tuck her chin while the provider or partner supports the legs. Step 4: coach the patient to take a deep breath and hold during the peak of a contraction then bear down and push for 10 seconds; repeat this as long as the contraction continues.	Step 1: head of bed up 30 degrees. Step 2: position patient, as she desires, on her back or either side. Step 3: the patient should be told simply to “do what comes naturally” or whatever the patient feels the urge to do while in bed.	Duration of second stage of labour was shorter in coached women in comparison to the uncoached women IG-3/67, CG-5/61, P = 0.385). No significant differences were found in prolonged second stage of labour, episiotomy, anal sphincter laceration, macrosomia, epidural, forceps, or oxytocin use.
Kirandeep Kaur, 2013, India [39]	To assess the effect of video on breathing exercises during labour on pain perception and duration of labour among the primigravida. Quasi experimental design, 40 (IG-20, CG-20).	Forty primigravida who were admitted in labour room were selected by purposive sampling technique. Mothers with respiratory diseases such as asthma, tuberculosis abdominal/uterine surgery were excluded from the study.	A video film of Hindi version (duration 10 minutes) which was developed with the storyline on breathing exercises during first stage of labour (slow breathing, fast breathing, pant-pant blow) and for second stage of labour (breathing exercises during childbirth) was shown prior to the onset of labour and re-demonstrations was obtained.	Routine care	The practice of breathing exercises during labour help to reduce pain perception and duration of first and second stage of labour. Pain perception at the latent, early and late active phases of first stage of labour showed statistical significant difference among experimental and control group (P < 0.01). Statistical significant difference (P < 0.01) was also observed in the duration of first stage of labour with mean duration (eight hours 48 minutes) in experimental group as compared to control group (nine hours 48 minutes). The mean duration of second stage of labour was also significantly less (P < 0.01) i.e. 24 minutes in experimental group as compared to 32 minutes in control group.
Tyseer Marzouk, 2019, Egypt [40]	To evaluate effectiveness of breathing exercise on reducing pain perception and state anxiety among primi parturients. Quasi-experimental design, 118 (IG-59, CG-59).	Participants were primi parturient in active phase of labour (i.e. ≥4 cm cervical dilation), aged between 20 and 35 years, at gestation weeks of 37 or beyond, did not receive analgesic or anaesthetic medication during the previous six hours, and not known to have a pre-existing respiratory disorders that may impair applying the breathing exercise.	Sit comfortably in leather armchairs during the exercise time. Keep one hand on the chest and the other on the abdomen at the umbilicus level. Gradually inspire air for four seconds; while nose in supine state. Slowly expire the inhaled air within six seconds through pursed lips; producing “Hoo” sound. Repeat step two and three during each contraction. During periods of rest, participants were taught to take breaths as in normal state.	Routine care	There was significant decline in women's perception of pain and state-anxiety in intervention group compared to control group (4.6 ± 2.0 vs. 5.9 ± 1.8 and 60.0 ± 7.8 vs. 64.3 ± 8.8) respectively. Intervention group subjects perceived lower pain and experienced lower state-anxiety compared to those of the control group after two hours (4.4 ± 2.1 vs. 5.8 ± 1.7 and 57.1 ± 7.8 vs. 63.8 ± 8.8) and after four hours (3.6 ± 1.4 vs. 5.7 ± 1.6 and 53.7 ± 7.8 vs. 63.3 ± 8.9 respectively. The parturient women who performed the breathing exercise had significantly shorter duration of the active phase of first stage of labour than those in the control group (5.9 ± 0.8 vs. 7.9 ± 0.8) hours, P < 0.001, while the duration of 2nd stage of labour did not differ significantly between the two groups (49.5 ± 4.5 vs. 50.4 ± 1.7) minutes, P = 0.160.

IG – intervention group, CG – control group, RCT – randomized controlled trial, G1 – group-1, G2 – group-2, G3 – group-3, G4 – group-4, MD – mean difference, CI – confidence interval