pituitary ovarian axis in the late phase of breast-feeding

This study was performed to evaluate the changes in the pituitary ovarian axis during the stage of escape from the inhibitory effect when breast feeding is prolonged. Also, to investigate the probability of occurrence of subclinical abortion during this stage. Volunteers from the attendee of the postpartum and well-baby clinic of Assiut University Hospital, were studied. Women who had been breast feeding for more than 6 months were frequently examined during one complete menstrual cycle or one month if still amenorrheic. They were having regular marital sexual relation. Examinations included sonographic scanning of the ovary and measurement of FSH, LH, prolactin, estradiol, progesterone and hCG. 7 patients out of the 8 who were amenorrheic showed either quiescent ovaries or partial follicular activity. 8 patients got pregnant during the period of observation. Out of 21 menstrual cycles studied 14 were ovulatory. Ovulation occurred in spite of persistence of hyperprolactinemia in most of them. These ovulatory cycles showed relatively high FSH values in the early and mid-follicular phases but the mid-cycle peak of FSH was occasionally absent. The mid-cycle peaks of E and LH, were lower than normal. The preovulatory rise in P was absent in most of the cycles. P and E production during luteal phase tended to be subnormal [LPD]. Prolongation of breast feeding is associated with resumption of folliculogenesis in spite of hyperprolactinemia. But it seems that the negative feed-back effect of E is exaggerated while the positive feed-back is subnormal. These findings may contribute to LPD which is common during this phase of breast feeding