Prenatal hormones in first-time expectant parents: Longitudinal changes and within-couple correlations.

OBJECTIVES: Expectant mothers experience marked hormone changes throughout the transition to parenthood. Although similar neuroendocrine pathways are thought to support maternal and paternal behavior, much less is known about prenatal hormone changes in expectant fathers, especially in humans.

METHODS: We examined longitudinal changes in salivary testosterone, cortisol, estradiol, and progesterone in 29 first-time expectant couples (N = 58). Couples were assessed up to four times throughout the prenatal period, at approximately weeks 12, 20, 28, and 36 of pregnancy. We also examined within-couple correlations in hormones. Data were analyzed using dyadic growth curve modeling.

RESULTS: As expected, women showed large prenatal increases in all four hormones. Men showed significant prenatal declines in testosterone and estradiol, but there were no detectable changes in men's cortisol or progesterone. Average levels of cortisol and progesterone were significantly positively correlated within couples.

CONCLUSIONS: The current study represents one of the most extensive investigations to date of prenatal hormones in expectant couples. It is also the first study to demonstrate prenatal testosterone changes in expectant fathers and within-couple correlations in progesterone. We discuss implications of these findings for parental behavior and adjustment.