According to the United States Centers for Disease Control and Prevention, between 11 and 20 percent of women who give birth each year in the U.S. have postpartum depression symptoms, which is the greatest risk factor for maternal suicide and infanticide. Given that there are 4 million births annually, this equates to almost 800,000 women with postpartum depression each year.

Current biological and psychosocial models of breastfeeding suggest that breastfeeding could possibly reduce a woman's risk for postpartum depression. However, prior studies only have looked at the initiation of breastfeeding and breastfeeding length. In addition, small and often homogenous samples have yielded ungeneralizable results lacking in statistical power with biased results due to higher levels of education, income, and proportions of white participants compared to the general population of the sampled country.

Researchers from Florida Atlantic University's Christine E. Lynn College of Nursing and collaborators are the first to examine current breastfeeding status in association with postpartum depression risk using a large, national population-based dataset of 29,685 women living in 26 states.

Results of the study, published in the journal Public Health Nursing, demonstrate that postpartum depression is a significant health issue among American women with nearly 13 percent of the sample being at risk. Findings showed that women who were currently breastfeeding at the time of data collection had statistically significant lower risk of postpartum depression than women who were not breastfeeding.

In addition, there is a statistically significant inverse relationship between breastfeeding length and risk of postpartum depression. As the number of weeks that women breastfed increased, their postpartum depression decreased. An unexpected finding was that there was no significant difference in postpartum depression risk among women with varying breastfeeding intent (yes, no, unsure).

Women suffering from postpartum depression, which occurs within four weeks and up to 12 months after childbirth, endure feelings of sadness, anxiety and extreme fatigue that makes it difficult for them to function. Women with postpartum depression who are not treated also may have negative outcomes, including difficulty bonding with and caring for their children, thoughts of harming themselves or their infant, and also are at an increased risk of substance misuse."

Christine Toledo, PhD, Study Senior Author and Assistant Professor, Christine E. Lynn College of Nursing, Florida Atlantic University

Woman who have experienced postpartum depression have a 50 percent increased risk of suffering further episodes of postpartum depression in subsequent deliveries. In addition, they have a 25 percent increased risk of suffering further depressive disorders unrelated to childbirth up to 11 years later. Postpartum depression increases maternal morbidity and is associated with increased risks for cardiovascular disease, stroke and type-2 diabetes.

For the study, Toledo and collaborators from the University of Miami School of Nursing and Health Studies, University of North Carolina School of Nursing, Chapel Hill, Seattle University of Nursing, and The University of British Columbia School of Nursing, analyzed dataset from the 2016 Pregnancy Risk Assessment Monitoring System (PRAMS) questionnaire to investigate the association of breastfeeding practices taking into consideration significant covariates such as age, race, marital status, education, abuse before and during pregnancy, cigarette smoking, among others.

"Findings from this important study suggest that breastfeeding is a cost efficient and healthy behavior that can decrease a woman's risk for postpartum depression," said Safiya George, Ph.D., dean, FAU Christine E. Lynn College of Nursing. "Nurses in particular play an important role in educating and promoting both the maternal health benefits of breastfeeding and infant benefits such as providing necessary nutrients and protecting them against allergies, diseases and infections."