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

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.