Breast-feeding during pregnancy in 503 women: does a psychobiological weaning mechanism exist in humans?
503 La Leche League mothers who found themselves pregnant while nursing completed questionnaires sent to them in 1977 to determine whether there is a biological basis for stopping breastfeeding when pregnancy occurs or if such weaning advice is just part of the general negative attitude of culture to breastfeeding. Results of the analysis show that pregnancy was unlikely to occur when the breastfed baby was 6 months old or less and that in 44% of the women, pregnancy did not occur until the nursing child was more than 15 months old. This finding confirms reports that lactation markedly inhibits fertility and the ovulation-menstruation cycle. 76% of the mothers had a positive reaction when the new pregnancy was learned. However, 69% of these mothers weaned their babies during pregnancy and only 31% continued nursing throughout the pregnancy. A psychobiological weaning triad of symptoms was reported, with 74% citing pain in the breast or nipples, 57% citing emotional discomfort connected with nursing and pregnancy, and 65% reporting a decrease in milk supply. Evidence suggests that the decrease in milk supply came in the 1st 4 months of pregnancy instead of later in the gestation. Of the 158 mothers who continued nursing throughout the pregnancy and breastfeeding 2 children thereafter, 77% expressed satisfaction with tandem nursing (nursing 2 children after delivery) and stated they would do the same thing again if faced with a similar situation.