Nutrition and development of infants from poor rural areas. III. Maternal nutrition and its consequences on fertility.

To test the hypothesis that malnutrition alters fertility, the reproductive pattern of a poor rural community with a high natality rate was studied. A late menarche age (15.5 +or- 1.5 years) and an early menopause (40.4 +or- 2.5 years) were found and resulted in a short reproductive period of 25 years. In all, there were 8.8 +or- 2.7 pregnancies and 7.9 +or- 2.9 deliveries during this period, but only 4.8 +or- 2.2 children reached adulthood. A longitudinal observation was made of 2 groups which were similar in all respects, except that one was supplemented and the other was not. Both groups lactated the entire time between pregnancies as well. The control group recovered fertility 14.0 +or- 4.0 months after delivery while the supplemented group did after only 7.5 +or- 2.6 months; this difference, as well as the difference in recovery times in the experimental group before and after supplementation, were highly significant (P0.001). It may be concluded that undernutrition reduced mothers' fertility in 2 potential ways. It may reduce a woman's reproductive life and it determines an increase in the period between deliveries of more than 40%. Therefore, the high natality rate in this community should not be explained by high individual fertility but rather by the sociocultural characteristics of the community.