lity.Post-Partum Anovulation in Nursing Mothers The length of the post-partum anovulatory period in nursing mothers has been reported to vary widely among different populations and a variety of mechanisms determining ing the length of the anovulatory interval has been considered by several investigators. Dominant among the hypotheses proposed have been :-h The Nutritional Hypothesis - Extended post-partum amenorrhea seen in poor developing countries is due to undernourishment and insufficient stores of body fat. h The Behaviour Hypothesis - Mothering and nursing practices play the primary role in determining the length of post partum amenorrhea. Taylor et al. have analysed breastfeeding and ovulation data from seventy-two mothers. A proportional hazards model of the data strengthened the hypothesis that a pattern of short frequent bouts of nursing define a risk-set of women less susceptible to post-partum ovulation than those who choose to nurse on a schedule of relatively lengthy and infrequent bouts. In contrast, no effect of maternal weight for height on the month-specific rate of post-partum ovulation could be detected in the study population comprised of American mothers trained in self-observation of fertility signs. A brief summary of their results follows.The proportion of the study population remaining anovulatory as a function of the number of months since childbirth. 1.00 0.75 0.50 0.25 0.00 0 5 10 15 20 25 y-axis : "Proportion remaining Anovulatory" x-axis : "Months Post-partum" FIG. 1. Post-partum anovulatory intervals for the study population ranged from 5.1 to 26.6 months. The mean interval was 14.1 months with a standard deviation of 5.2 months. The median anovulatory interval was 13.9 months, with the first and third quartiles occurring at 10.8 a...
