Pregnant women with posttraumatic stress disorder and risk of preterm birth

Posttraumatic stress disorder (PTSD) occurs in about 8% of pregnant women. Stressful conditions, including PTSD, are inconsistently linked to preterm birth. Psychotropic treatment has been frequently associated with preterm birth. Identifying whether the psychiatric illness or its treatment is independently associated with preterm birth may help clinicians and patients when making management decisions.

To determine whether a likely diagnosis of PTSD or antidepressant and benzodiazepine treatment during pregnancy is associated with risk of preterm birth. We hypothesized that pregnant women who likely had PTSD and women receiving antidepressant or anxiolytic treatment would be more likely to experience preterm birth.

Longitudinal, prospective cohort study of 2654 women who were recruited before 17 completed weeks of pregnancy from 137 obstetrical practices in Connecticut and Western Massachusetts.

Posttraumatic stress disorder, major depressive episode, and use of antidepressant and benzodiazepine medications.

Preterm birth, operationalized as delivery prior to 37 completed weeks of pregnancy. Likely psychiatric diagnoses were generated through administration of the Composite International Diagnostic Interview and the Modified PTSD Symptom Scale. Data on medication use were gathered at each participant interview.

Recursive partitioning analysis showed elevated rates of preterm birth among women with PTSD. A further split of the PTSD node showed high rates for women who met criteria for a major depressive episode, which suggests an interaction between these 2 exposures. Logistic regression analysis confirmed risk for women who likely had both conditions (odds ratio [OR], 4.08 [95% CI, 1.27-13.15]). For each point increase on the Modified PTSD Symptom Scale (range, 0-110), the risk of preterm birth increased by 1% to 2%. The odds of preterm birth are high for women who used a serotonin reuptake inhibitor (OR, 1.55 [95% CI, 1.02-2.36]) and women who used a benzodiazepine medication (OR, 1.99 [95% CI, 0.98-4.03]).

Women with likely diagnoses of both PTSD and a major depressive episode are at a 4-fold increased risk of preterm birth; this risk is greater than, and independent of, antidepressant and benzodiazepine use and is not simply a function of mood or anxiety symptoms.