Do Parental Hormone Levels Synchronize During the Prenatal and Postpartum Periods? A Systematic Review

Physiological synchrony is the phenomenon of linked physiological processes among two or more individuals. Evidence of linkage between dyads has been found among a broad range of physiological indices, including the endocrine systems. During the transition to parenthood, both men and women undergo hormonal changes that facilitate parenting behavior. The present review sought to address the question as to whether hormonal synchronization occurs among expecting or new parents. A systematic literature search yielded 13 eligible records. The evidence of cortisol synchrony during the prenatal period, with additional testosterone, prolactin, and progesterone covariations in the time leading up to childbirth, was found to be most significant. During the postpartum period, parental synchrony was reported for oxytocin, testosterone, and cortisol levels. The implications of these covariations were found to translate into adaptive parenting behaviors and the facilitation of romantic bond. Associations with infant development were also reported, suggesting far-reaching effects of hormonal synchrony outside the parental dyad. The results highlight the importance of physiological interrelatedness during this sensitive period, underscoring the need for further research in this field. In view of the limited data available in this research domain, we have put forward a framework for future studies, recommending the adoption of standardized research protocols and repeated collections of specimens.