The effect of improved nutrition on plasma prolactin concentrations and postpartum infertility in lactating Gambian women.

A substantial increase in food consumption of lactating Gambian women has been shown to be associated with a reduction in their plasma prolactin concentration. Women receiving food supplements during pregnancy as well as in lactation exhibited an even greater lowering of the postpartum plasma levels of this hormone. Consequently prolactin values of supplemented women returned more quickly to levels which allowed the resumption of menstrual and ovulatory activity. Concurrent measurements of the plasma concentrations of estradiol and progesterone in addition to prolactin allowed the calculation of prolactin values at which half the lactating women could be expected to have resumed menstruation and ovulation. These values were 1007 and 759 microU/ml, respectively. Dietary improvement during lactation alone resulted in these critical prolactin concentrations being reached 21 wk earlier than in nonsupplemented counterparts, while those receiving the extra food in both pregnancy and lactation showed a 35-wk shortening of postpartum amenorrhea and infertility.