Postnatal developmental changes in the pituitary-ovarian axis in preterm and term infant girls

Abstract

Context: Postnatal pituitary-testicular activation in infant boys is well characterized. However, the ovarian response to pituitary activation in infancy is less well understood. Objective: The aim of the study was to compare postnatal developmental changes in the pituitaryovarian axis in preterm and term infant girls. Participants and Design: Sixty-three infant girls, divided into three groups according to gestational age(GA) [i.e. full term (FT;n=29;GA,37-42 wk), near term (NT;n=17;GA,34-37 wk),andpreterm (PT; n = 17; GA, 24-34 wk)] were examined monthly from 1 wk (D7) to 6 months (M1-M6) of age and reexamined at the corrected age of 14 months (cM14). Main Outcome Measures: We performed a longitudinal follow-up of urinary FSH and serum anti-Müllerian hormone (AMH) levels and the number of follicles in transabdominal ovarian ultrasonography. Results: The postnatal FSH surge was stronger and more prolonged in NT and PT girls than in FT girls (P≤0.001). Increased folliculogenesis and a rise in AMH levels were observed in all three groups after the FSH surge. In NT and PT girls, follicular development was delayed in comparison with FT girls, and a decrease in high FSH levels around the 40th postmenstrual week was temporally associated with the appearance of antral follicles in ultrasonography and an increase in AMH levels. Conclusions: The postnatal FSH surge results in transient ovarian stimulation in termandpreterm girls. A delay in ovarian folliculogenesis shown in ovarian ultrasonography and by low serum AMH levels may provide an explanation for the exaggerated FSH surge in NT and PT girls. Copyright © 2011 by The Endocrine Society.