Because long-term, undetected depression often requires more care and rigorous treatment, the findings highlight the importance of doctors being aware of exactly how long the mother has been experiencing symptoms.
Pinpointing the onset time can influence how the doctor treats the woman’s depression, such as intervening sooner with psychiatric help, if needed, said Sheehan Fisher, the study’s corresponding author and an instructor of psychiatry and behavioral sciences at Northwestern University Feinberg School of Medicine.
“There’s a difference between postpartum depression and depression that started before or during the pregnancy. It’s not a homogenous disorder, ” Fisher said.
“When clinicians see a mother during the postpartum period and diagnose her with depression, it’s important for them to ask how long this depression has been an issue so they can assess the longevity and severity.”
The study is one of the first to compare the rates of depression in mothers at the three onset time points: pre-pregnancy, during pregnancy (prenatal), and during the postpartum period. The findings show that 24.9 percent of participants developed depression pre-pregnancy, 36.7 percent developed it prenatally and 38.4 percent developed depression postpartum.
Mothers who develop new cases of postpartum depression are more likely to be Caucasian, older, educated, married, or cohabitating, and have private health insurance than those whose depression begins before or during pregnancy, the study found.
“Mothers who develop postpartum depression often experience protective risk factors such as better access to resources, fewer children, and are more mature, which helps them adapt to the stress of pregnancy,” Fisher said.
“Once their babies are born, they show more obsessive-compulsive symptoms — like over-worrying about their baby’s health — than mothers who developed depression before or during pregnancy.”
Women who developed depression pre-pregnancy were more likely to experience hypersomnia or trouble falling asleep. They were also more likely to experience symptoms of psychosis, such as paranoia, than women who developed depression during or after pregnancy. Their episodes of postpartum depression were also more severe than women with other onset periods.
The percentage of mothers who had a bipolar disorder — which Fisher said is more severe than unipolar depression — was significantly higher among mothers whose depression onset was during the pre-pregnancy period (38.7 percent), compared with prenatal (22.6 percent), and postpartum (17.9 percent).
Agitation was a distinct symptom that differentiated mothers with unipolar and bipolar depression in the study. Mothers with bipolar disorder who developed depression during pregnancy showed the highest levels of agitation.
For the study, researchers evaluated depression symptoms during the four- to six-week postpartum period for 727 women from an urban women’s hospital in Pittsburgh, Penn. This period was chosen because women typically visit their doctors for post-birth evaluations six weeks after birth, and the four- to six-week period is linked to the highest depression onset.
The findings are published in the Journal of Affective Disorders.
Source: Northwestern University