Third-trimester oxytocin blood levels may help predict the severity of postpartum depression symptoms in women with a history of major depressive disorder, suggests new research in Archives of Women’s Mental Health. The finding may lead the way to a biomarker for prenatal screenings for postpartum depression risk, the authors wrote.
“Many mothers with postpartum depression feel that they are failing because they expect that they should be happy, which decreases the likelihood that they will seek or accept help,” wrote Suena H. Massey, MD, of Northwestern University Feinberg School of Medicine, and her colleagues. “If women who are destined to develop postpartum depression could be accurately identified during pregnancy, prevention could be implemented.”
The researchers measured oxytocin concentrations in the blood of 66 healthy pregnant women in their third trimesters. None of the women had a current mood disorder or was receiving treatment for depression or anxiety, but 13 had a history of major depressive disorder. The women with and without past depression shared similar demographic factors and birth outcomes, and oxytocin levels among them did not differ significantly, regardless of depression history.
When the women were 6 weeks postpartum, the researchers assessed their depressive symptoms and compared those to the women’s oxytocin plasma levels and depressive symptoms before giving birth. Though none of the women met the diagnostic threshold for depression before delivery, those with greater symptoms during the third trimester also had greater severity of postpartum depression symptoms.
Oxytocin levels were not associated with the severity of postpartum depression symptoms when adjusted for third-trimester symptoms. However, oxytocin levels did predict the severity of postpartum depression symptoms among women with a history of depression: higher oxytocin levels correlated with greater symptom severity.
These findings differ from past studies comparing oxytocin levels and postpartum depression symptoms, and the authors explore several possible reasons for that, such as oxytocin increases following affiliative interactions with the study personnel, differences in previous study populations, or oxytocin interaction with other peptide receptors, among other reasons.
“Confirmation of our findings in larger, more representative samples can contribute to a more in-depth understanding of the etiology of perinatal depression and may lead to improved prediction of postpartum depression,” the authors wrote. “In the future, availability of an ‘objective’ blood test could help to challenge misperceptions or stigma associated with depression by providing biological evidence about risk for this condition.”
Massey SH, Schuette SA, Pournajafi-Nazarloo H, Wisner KL, Carter CS. Interaction of oxytocin level and past depression may predict postpartum depression symptom severity. Arch Women’s Mental Health. 2016; Mar 8. [Epub ahead of print]