Postpartum depression may persist 3 years after giving birth

The rest of the women experienced low levels of depression throughout the three-year span, the study, published in the journal Pediatrics, reported.

"The American Academy of Pediatrics recommends that pediatricians screen mothers for postpartum depression at well-child visits at one, two, four and six months after childbirth," said the study authors from the National Institute of Child Health and Human Development (NICHD) in the US.

For the study, the researchers analysed data from the Upstate KIDS study, which included babies born between 2008 and 2010 from 57 counties in New York state.

The study followed 5,000 women for three years after their children were born.

Researchers assessed women's symptoms through a brief, five-item depression screening questionnaire, but the study did not clinically diagnose depression in the women.

Women with underlying conditions, such as mood disorders and/or gestational diabetes, were more likely to have higher levels of depressive symptoms that persisted throughout the study period.

Researchers identified four trajectories of postpartum depressive symptoms and the factors that may increase a woman's risk for elevated symptoms.

The findings suggest that extending screening for postpartum depressive symptoms for at least two years after childbirth may be beneficial, the authors write.

"Our study indicates that six months may not be long enough to gauge depressive symptoms," said study author Diane Putnick from NICHD.

"These long-term data are key to improving our understanding of mom's mental health, which we know is critical to her child's well-being and development," Putnick added.

Future studies should include a more diverse, broad population to provide more inclusive data on postpartum depression, the study noted.