The relationship between hormones and human parturition

The objective of the present review was to give an overview of some hormonal fluctuations observed in the setting of human term and preterm parturition. Prolactin, cortisol, estrogen, progesterone, and some of their precursors such as dehydroepiandrosterone sulfate (DHEA-S) were reviewed. Statistically significant differences were found when comparing cortisol, 17β-estradiol, and DHEA-S concentrations at term parturition between women in labor and those not in labor. In preterm labor, higher concentrations of cortisol, 17β-estradiol, and DHEA-S were found at labor than in women who after successful treatment delivered at term. No significant changes were seen in prolactin concentrations between women in labor and those not in labor, but they were higher in patients with preterm labor when compared to term labor. Progesterone concentrations showed no difference in preterm labor and term labor. However, maternal progesterone/17β-estradiol ratios were significantly lower in women delivered prematurely than in those delivered at term. The changes in hormonal ratios may play a more important role than changes in their absolute concentrations. Based on these observations, it seems that preterm and term parturition are two different endocrinological processes.