ACTIVATION OF THE HYPOTHALAMIC-PITUITARY-GONADAL (HPG) AXIS IN PRETERM FEMALES

Abstract

Precocious puberty was observed in a preterm ( 27 wks post-conceptional age - PCA) female. At 41 wks PCA, estradiol (E2) levels were elevated (282 pg/ml). By 13 months PCA, E2 decreased spontaneously (18 pg/ml) and pubertal changes regressed. However, pelvic ultrasonography revealed the development of ovarian cysts. In order to interpret these findings and determine their significance, we studied 6 normal preterm female infants (PCA ≤34 wks) during the first month of postnatal life. We measured: a) E2 - max > 30,000 pg/ml on day of birth (DOB), b) LH - max 196 mIu/ml on DOB, c) FSH - max 125.2 mIu/ml 3 wks after birth, d) 17-hydroxyprogesterone - max 4320 ng/dl on DOB, and e) DHEA-S - max 429 μg/dl on DOB. As in full term infants, E2 was highest on the DOB and decreased to prepubertal values within 1 month. In contrast, gonadotropin levels were variable but remained elevated throughout this period.Conclusions: Although in most preterm females elevated gonadotropin levels persist for at least 1 month, the same is not true for E2. These data suggest that the HPG axis is activated in premature female infants prior to their would be term delivery. The index case differed in that elevated E2 levels persisted and ovarian cysts developed.