Relationships between serum prolactin levels and follicle stimulating hormone response to luteinizing hormone-releasing hormone during early puerperium.

The effect of serum prolactin (Prl) levels on pituitary response to iv luteinizing hormone-releasing hormone (LRH) (100 micrograms) was studied in 23 normal puerperal women on day 1 post-partum. All women had an uneventful full-term pregnancy and delivery. The LRH test was repeated in 8 of the women on day 3 and in the remaining 15 on day 6 post-partum. Serum Prl levels were high on days 1 and 3, but decreased significantly on day 6 (P less than 0.01). No pituitary FSH response to LRH stimulus was found on day 1 post-partum in all 23 women. In those who were given placebo, FSH levels in serum did not change in response to LRH on day 3 (4 women), but increased significantly on day 6 (5 women) in all subjects (P less than 0.05). Conversely, when oral metoclopramide was given from day 1 to 6 (10 women) the responsiveness of FSH to LRH on day 6, found in the placebo group, was not observed. Early reduction of serum Prl values on day 3 post-partum by bromocriptine treatment from day 1 to 3 (4 women) did not accelerate the FSH response to LRH. These results suggest an inhibitory effect of elevated serum Prl on the pituitary FSH response to LRH in women during early puerperium.