Mid-pregnancy androgen levels are negatively associated with breastfeeding

Objective. Breastfeeding depends on endocrine changes during pregnancy. The association between gestational hormones and lactation has been sparsely investigated. Previously, androgens were used for lactation inhibition. We investigated a possible association between second trimester maternal androgen levels and breastfeeding. Design. Prospective observational study. Setting. University hospital setting. Population. Women from a random sample of pregnancies (n = 63) and from a group with an increased risk for giving birth to a small-for-gestational age newborn (n = 118) were included. All participants had singleton pregnancies and one or two previous births. Methods. Maternal androgen levels were measured in gestational week 25. The association with reported breastfeeding was explored by univariate and multivariate linear regression analyses. Analyses were adjusted for factors known to be associated with breastfeeding. Main outcome measures. Breastfeeding at six weeks, three months, and six months postpartum. Results. In the random group, breastfeeding at three and six months was negatively associated with maternal testosterone, androstendione, and free testosterone index levels. After correction for maternal age, education and smoking, breastfeeding at both three and six months was negatively associated with the free testosterone index. In the group of women with an increased risk for giving birth to a small-for-gestational age newborn, breastfeeding at six weeks and three months was associated negatively with maternal dehydroepiandrosterone and this association persisted after correction for maternal age, education, and smoking. Conclusions. Maternal androgen levels in mid-pregnancy are negatively associated with breastfeeding.