Thyroliberin and gonadoliberin tests during pregnancy and the puerperium

Highly specific and sensitive radioimmunoassays for HTSH, HFSH and HLH have been used in order to investigate pituitary thyrotrophic and gonadotrophic functions of pregnant and puerperal women. The radioimmunoassay system for HFSH, using reagents prepared in our laboratory, is described. Thirty-three women were studied during pregnancy and post-partum. Forty-one TRH tests were performed. Basal levels of TSH, and increase in serum TSH after intravenous injection of TRH were similar in pregnant and puerperal women and in a control group. Thirty-three LH-RH tests were also performed. Basal levels of LH and FSH remained undetectable throughout pregnancy and in early puerperium. Furthermore, after intravenous injection of LH-RH neither LH nor FSH activity could be detected. It has thus been demonstrated that pituitary responsiveness to TRH during pregnancy and the puerperium is similar to that of non-pregnant young women. In contrast, a complete cessation of pituitary gonadotrophic functions is observed during the same period.