Many women experience depression during pregnancy and in the early months after childbirth. Previous studies showed a link between docosahexanoic acid (DHA) and positive mental health. DHA is also known to be important for optimal brain development in the growing fetus and in infants.
Based on these earlier findings, researchers supported by the Pediatric Growth and Nutrition Branch conducted a study to examine whether symptoms of depression during pregnancy affect the concentration of DHA in breast milk. Researchers conducted a survey of 287 women to assess whether they experienced depressive symptoms. Researchers collected breast milk samples from the same women 4 months after childbirth to measure the concentration of DHA.
The results from the study showed that women who reported depressive symptoms in the first 20 weeks of pregnancy had lower concentrations of DHA in their breast milk. The same association was not found in women who reported depressive symptoms later in pregnancy.
Because depression prior to pregnancy was not measured, it was unclear whether the women in this study were experiencing chronic depression or temporary depression due to stress or hormonal changes associated with pregnancy. However, because levels of DHA measured in breast milk are reflective of long-term influences on the body to store DHA over time, low levels of DHA in breast milk are likely associated with chronic depression (PMID: 22223516).