Estrogens delay the postpartum recovery of the LH-RH-induced gonadotropin release.

In 27 healthy postpartum women, who were neither lactating nor receiving any therapy, LH-RH stimulation tests (50 micrograms i.v.) were performed on days 7, 14, 21 and 28 of the puerperium. In a second group of 9 postpartum women an i.m. injection of 10 mg estradiol valerianate was administered within the 3rd postpartum day, and an LH-RH stimulation test was performed on days 14 and 21 of the puerperium. Blood was withdrawn at standard intervals and LH and FSH measured by radioimmunoassay. No significant FSH and LH response was found on day 7. On day 14 there was a significant release of FSH but no LH was released. On days 21 and 28 there was a significant release of FSH and LH but the magnitude of the FSH response was greater than that of the LH release. The administration of estrogens did inhibit the recovery of the pituitary from its refractoriness: on day 14 no release of LH and FSH was observed; on day 21, only a significant release of FSH could be detected in the second group of postpartum women. This emphasizes the major role played by steroids in the regulation of the hypothalamo-pituitary-gonadal function.

Cord serum prolactin in relation to the time of the day, the sex of the neonate and the birth weight.

Serum prolactin was measured in 581 blood samples collected immediately after birth from 563 single new-born and from 9 pairs of twins. Cord serum prolactin is high at birth: the mean level is some 5 times higher than in adults. There is no sex difference in cord serum prolactin concentration in the neonate. Mean serum prolactin is significantly higher at 1.00 and 2.00 a.m. Thus a circadian periodicity in serum prolactin concentration seems to appear already during foetal life well before the organization of sleep rhythm. Cord serum prolactin increases with birth weight ranging from 1500 g to 3500 g. Thus, the control of levels of circulating prolactin changes during foetal life resulting in a progressive increase starting from mid-pregnancy. Mean cord serum prolactin at birth is lower in twins than in single new-borns. There is no significant difference in serum prolactin between the first and the second twin.

Plasma LH-HCG, 17 -estradiol, estrone and progesterone monitoring around ovulation and subsequent nidation.

PIP: At the University Hospital in Louvain, Belgium, plasma hormonal fluctuations in 6 women, aged 16-46, were studied. Measurements were made during the nonpregnant state and in the 4 women who conceived also in the period around nidation. Measurements during the nonpregnant state yielded expected results: Preovulatory midcycle luteinizing hormone (LH) surge preceded by increase of estrone and estradiol, sudden fall of estrogens and rise of progesterone during or just after LH surge, and secondary estrogen rise together with progesterone peak during the luteal phase accurred. In the women implantation occurred, human chorionic gonadotropin (HCG) started to rise sharply 10 or 11 days after the LH surge. Progesterone and estrogen levels remained high during the implantation period. In the patient who aborted at 17 weeks of pregnancy, the HCG rise was slower and the secondary rise of estradiol was rather limited; progesterone levels, however, appeared to be normal. An estradiol surge may occur just prior to implantation.^ieng