Abstract

PIP: It is possible that the lower levels of prolactin associated with improved maternal nutrition could result in shorter periods of postpartum infertility. The authors tested this hypothesis by studying postpartum amenorrhea and fertility when the diet of lactating Gambian women was improved by supplementation. 119 women living in the village of Keneba were studied earlier. Blood samples used in the prolactin study were analyzed for progesterone and estradiol; samples from the supplemented group were also obtained. Estradiol and progesterone concentrations were measured by radioimmunoassay kit. Level of plasma estradiol rose sharply (reflecting return of menses) 66 weeks postpartum in unsupplemented mothers but much earlier, 42 weeks, in supplemented mothers. The supplemented group had increased plasma progesterone level (suggesting recurrence of ovulation) by 54 weeks. By 78 weeks, mean values did not differ significantly from nonpregnant, nonlactating values in Gambian women. Before supplementation, 19.2% of 180 conceptions occurred before 18 months postpartum; after supplementation, the proportion rose to 33% out of 54 conceptions. Dietary supplementation was attributed to a decrease in duration of lactational amenorrhea and infertility by at least 6 months, resulting in decrease in birth interval. As the mothers breastfed 10 to 16 times daily during the study period and there were no other environmental or socioeconomic changes introduced in the village during the 2-year study period, the effect was attributed solely to maternal dietary improvement. The study confirms the hypothesis that improving the diet of malnourished lactating women can shorten birth intervals and result in an increase in birth rate.