Does breastfeeding induce spontaneous abortion?

To verify the hypothesis that even if breastfeeding is continued during pregnancy, there are no harmful effects on pregnancy.

The outcomes of pregnancies in mothers who continued breastfeeding during pregnancy were studied. One hundred and ten pregnant women were recruited who had one full-term baby, no experience of premature birth or abortion, and who continued to breastfeed at diagnosis of pregnancy. Age and pregnancy history matched 774 pregnant women were selected as a control group. All of the control women stopped breastfeeding at least 3 months before becoming pregnant. We reviewed the outcome of each pregnancy retrospectively from patient records. Statistical analysis was conducted using the chi(2) test.

Eight of 110 pregnancies (7.3%) resulted in spontaneous abortion in the breastfeeding group, and 65 of 774 pregnancies (8.4%) in the control group. There were no statistically significant differences between the two groups (P > 0.05).

Even if the mother is pregnant, breastfeeding should be continued until natural weaning occurs. Further study is required to conclude safety of breastfeeding and premature birth.