A study of prolactin, follicle-stimulating hormone, and luteinizing hormone in puerperium: spontaneous variations and the effect of metergoline.

In 80 normal puerperae, serum follicle-stimulating hormone (FSH), luteinizing hormone (LH), including human chorionic gonadotropin (hCG/LH), and prolactin (PRL) levels were evaluated 6 to 29 hours after vaginal delivery. In these puerperae, PRL levels were higher and FSH levels were lower than in menstruating women; hCG/LH levels were very high, due to persisting hCG levels. The values of the three hormones showed a log-normal distribution, and no relationship was found between the three hormones considered in pairs. Thirty-six puerperae chosen from the above 80 were followed during a 5-day period: 24 were not able to breast-feed their babies and were treated with metergoline, an antiserotoninergic agent able to prevent puerperal lactation, 8 or 12 mg/day; 12 additional puerperae, nursing their babies, were evaluated as controls. In lactating women PRL and FSH levels remained steady during the observation period, while hCG/LH levels progressively decreased. Metergoline lowered PRL levels, when employed at both dosages, and FSH levels only at the higher dosage, without affecting the decline of hCG/LH levels. Since dopaminergic drugs are known to lower serum LH levels and not to affect or to increase FSH levels, our data indicate that metergoline might act through a mechanism of action different from dopaminergic drugs.