A comprehensive edition of each issue of Research Summaries for Normal Birth, including fuller discussions of research methods and results, will now appear in The Journal of Perinatal Education.

Stremler, R., Hodnett, E., Petryshen, P., Stevens, B., Weston, J., Willan, A. R. (2005). Randomized controlled trial of hands-and-knees positioning for occipitoposterior position in labor. Birth, 32(4), 243-51. [Abstract]

Summary: In this randomized controlled trial, researchers evaluated the effectiveness of hands-and-knees position in labor for rotating a fetus from an occipitoposterior (OP) position, alleviating back pain, and improving perinatal outcomes. Healthy, low-risk women in the first stage of labor with an OP fetus confirmed by ultrasound were randomized to either the hands-and-knees group (n=70) or the control group (n=77). Those in the hands-and-knees group were asked to spend as much time as possible in the hands-and-knees position over a period of 60 minutes, for a minimum of 30 total minutes. They were then encouraged to use the position according to their preference for the remainder of labor. Those in the control group were able to use any position except a hands-and-knees position (or similar position that resulted in the suspension of the abdomen) during the 60-minute study period. Following the study period, they were not specifically encouraged to use a hands-and-knees position but were not prevented from doing so.

Persistent back pain scores were significantly reduced in the women who used the hands-and-knees position compared with those in the control group. While fetal rotation to the optimal OA position (confirmed by ultrasound after the study period) occurred more frequently in the hands-and-knees group (16% vs. 7%, p=0.18), this association failed to reach statistical significance. Similarly, a non-significant trend that favored use of hands-and-knees positioning was found for operative delivery, head position at the time of birth, 1-minute Apgar score, and time from randomization to birth. Hands-and-knees positioning was apparently acceptable to women, evidenced by the fact that 84 percent of survey respondents said they would use the position again in a future labor, with increased comfort and improved labor progress listed as the most common reasons.

Significance for Normal Birth: This study provides good quality evidence that use of hands-and-knees position in labor is acceptable to women and reduces persistent back pain when the baby is OP. No evidence of harm was found and, indeed, a consistent trend of improved perinatal outcomes was found in the group of women randomized to use the hands-and-knees position. It is possible that a larger study would have the power to detect statistically significant differences in such outcomes as cesarean or instrumental birth, length of labor, and neonatal well-being.

When a baby is OP during labor, the risk of cesarean section or instrumental vaginal birth is high unless the fetal head rotates to a more favorable position. Simple, non-pharmacologic methods such as encouraging hands-and-knees positioning have the potential to improve the likelihood of normal, spontaneous birth without introducing unnecessary risk to the mother or baby.

Freedom of movement throughout labor allows women to work with their bodies’ cues to use the positions that are most comfortable and promote labor progress. Honoring the laboring woman’s preference for non-supine positions in labor and birth may – not coincidentally! – bring about the dual benefit of improving her satisfaction with the birth experience and promoting normal birth.

Buschsbaum, G. M., Duecy, E. E., Kerr, L. A., Huang, L., Guzick, D. (2005). Urinary incontinence in nulliparous women and their parous sisters. Obstetrics and Gynecology, 106(6), 1253-8. [Abstract]

Summary: In this matched-pair study, researchers evaluated symptoms and signs of urinary incontinence in pairs of post-menopausal sisters where one sister was nulliparous (having never given birth) and the other was parous (having given birth vaginally at least once). All sister pairs (n=143 pairs) completed questionnaires about their demographic characteristics, medical histories, and presence of urinary incontinence within the previous 4 weeks. Survey questions also served to measure the severity of symptoms and to classify the type of incontinence: stress incontinence (associated with laughing, coughing, etc.), urge incontinence (associated with strong urge to void, or precipitated by the sound of running water, etc.), or mixed incontinence (showing symptoms of both stress and urge incontinence). Sister pairs who were willing to complete a detailed clinical evaluation (n=101) underwent physical examinations by examiners who were masked to the continence status and obstetric history of the participants.

There was no significant difference detected between the rate of urinary incontinence between nulliparous women (47.6%) and their parous sisters (49.7%). Similarly, no difference was found in the type of incontinence, the severity or the symptoms, or the perceived impact on activities of daily living. Most of the sister pairs (63%) shared the same continence status. Among the discordant sister pairs (where one suffered incontinence and one did not), the parous sister was incontinent 53% of the time and the nulliparous sister was incontinent the remaining 47% of the time. This difference was not statistically significant (p=0.82).

Significance for Normal Birth: Vaginal birth has been attacked on the grounds that it weakens pelvic floor muscles, resulting in incontinence later in life. This line of thinking has fostered a movement to promote elective cesarean section as a means to prevent pelvic floor injury. However, a growing body of literature supports the theory that factors such as family history, obesity, cigarette smoking, and age are better predictors of urinary incontinence than history of vaginal birth. By using sister pairs, the authors of this study were able to control for familial factors that affect pelvic floor function and conclude that “damage to the pelvic support systems during vaginal delivery does not appear to increase the prevalence or severity of incontinence later in life” (p. 1257).

In the midst of the debate about the potential role of cesarean surgery in protecting the pelvic floor, important evidence about obstetric management of vaginal birth has received comparatively little attention. Maternity care practices such as episiotomy, coached pushing, and instrumental birth appear to significantly increase the likelihood of incontinence in women who have given birth vaginally. Curbing the overuse of these practices is likely to have a much greater impact on women’s pelvic floor functioning than further increasing the rate of cesarean birth.

Bloom, S. L., Casey, B. M., Schaffer, J. I., McIntire, D. D., Leveno, K. J. (2006). A randomized trial of coached versus uncoached maternal pushing during the second stage of labor. American Journal of Obstetrics and Gynecology, 194, 10-3. [Abstract]

Summary: This randomized controlled trial evaluated the impact on perinatal outcomes of coached versus uncoached pushing during the second stage of labor. Nulliparous women with low-risk, term pregnancies in spontaneous labor without epidural analgesia were included in the study. About half of the participants (n=163) were randomized to coached pushing with a closed glottis (i.e., while holding one’s breath), while the other half (n=157) were not given any specific instruction on how to push. Both groups were attended by certified nurse-midwives throughout labor and birth.

The average length of second stage was 13 minutes shorter in the coached pushing group (46 minutes versus 59 minutes, p=.014), however there was no significant difference in the likelihood of pushing beyond 2 hours or 3 hours. No other statistically or clinically significant differences in mode of birth, perineal integrity, or neonatal outcome were found between the two groups.

Significance for Normal Birth: Coached pushing provided no clinically important benefits in this well designed trial. Previous research has suggested that coached pushing may be harmful to the woman’s pelvic floor muscles and may be associated with adverse neonatal outcomes. The widespread use of coached pushing undermines women’s intrinsic knowledge of how to give birth safely and gently. In the absence of evidence that this practice is beneficial and with mounting evidence that it may contribute to poor perinatal outcomes, routine use of coached pushing should be abandoned.

This study is an important addition to the literature because it evaluates coached versus physiologic pushing in the absence of epidural analgesia, which complicates second stage management. Previous research has shown that coached pushing is associated with poor perinatal outcomes when an epidural is used.

Stuebe, A. M., Rich-Edwards, J. W., Willett, W. C., Manson, J. E., Michels, K. B. (2005). Duration of lactation and incidence of type-2 diabetes. JAMA, 294(20), 2601-10. [Abstract]

Summary: In this analysis of two large observational study cohorts, researchers evaluated the impact of duration of breastfeeding on the likelihood of developing type-2 diabetes later in life. A total of 83,585 parous women in the Nurses Health Study (NHS) cohort and 73,418 in the Nurses Health Study-II (NHS-II) cohort reported lactation history. Data on body-mass index (BMI), diet, exercise, smoking status, history of gestational diabetes, and other risk factors were also collected and multiple analyses were conducted to determine and control for the influence of these potential confounders.

Among women who had given birth within the previous 15 years, the risk of developing type-2 diabetes was decreased by 15% for each year of lactation in the NHS cohort and 14% in the NHS-II cohort, after controlling for diabetes risk factors. The association was much more modest in women who had given birth more than 15 years previously, and no association was observed among postmenopausal women. No decreased risk was observed in women with a history of gestational diabetes, who are at markedly higher risk of developing type-2 diabetes later in life.

Duration of exclusive (versus total) breastfeeding was even more strongly associated with decreased risk, as was longer duration of breastfeeding per pregnancy. For instance, 1 year of lactation for 1 child resulted in a 44% reduction in age-adjusted risk, whereas 1 year of lactation between 2 children resulting in a 24% reduction in age-adjusted risk. The researchers also found evidence that the beneficial association begins to develop after 6 months of lactation. Use of medications to artificially suppress lactation was associated with a 46% increase in the risk of developing type-2 diabetes.

Significance for Normal Birth: Breastfeeding is the natural culmination of a normal birth and is associated with a long list of health benefits for both the baby and the mother. Evidence suggests that many of the care practices that undermine normal birth also undermine women’s ability to successfully initiate exclusive breastfeeding (Kroeger, 2004). This study points to a novel long-term effect of interrupting the breastfeeding relationship. Type-2 diabetes is associated with many adverse health outcomes, poor quality of life, and a rapidly growing burden on the health care system. Working to help women initiate and continue breastfeeding, with exclusive breastfeeding for at least the first six months, may help prevent or delay the onset of type-2 diabetes. Furthermore, prevention of diabetes may be a powerful incentive for women to choose breastfeeding and to continue breastfeeding beyond the child’s infancy.

References:

Kroeger, M. (2004) The impact of birthing practices on breastfeeding: protecting the mother and baby continuum. Jones and Bartlett, Sudbury, MA.