The most recent study was published in the journal Sleep, a major sleep-medicine journal not necessarily known for its support of breastfeeding. This was a study of 2,830 women at 7 weeks postpartum (Dorheim et al., 2009). The researchers found that disrupted sleep was a major risk factor for postpartum depression. But here is where it really gets interesting. When considering what disrupted sleep, they found that the following factors were related to disturbed sleep: depression, previous sleep problems, being a first-time mother, a younger or male infant, and not exclusively breastfeeding. In other words, mothers who were not exclusively breastfeeding had more disrupted sleep and a higher risk of depression.
Kathleen Kendall-Tackett, Ph.D., IBCLC is a health psychologist, board-certified lactation consultant, and La Leche League Leader. She is clinical associate professor of pediatrics at Texas Tech University School of Medicine in Amarillo, Texas.