Trauma and PTSD in Pregnancy Set Women on a Worsening Sleep Path That Predicts Postpartum Depression

Pregnancy is supposed to be a time when the body prepares for a new life, but for millions of women it is also a time when sleep quietly falls apart. Hormonal surges, physical discomfort, and the psychological weight of impending motherhood conspire to fragment the nights of as many as 79 percent of pregnant women. A new longitudinal study published in the Journal of Behavioral Medicine now shows that this disruption is not random. Instead, expectant mothers appear to travel along one of two distinct sleep trajectories across pregnancy, and which path they follow is strongly shaped by their history of trauma and mental health. Most strikingly, women whose sleep deteriorates as pregnancy progresses report significantly more depressive symptoms after childbirth, suggesting that sleep may be one of the earliest and most treatable warning signs of postpartum depression.

The research team, led by Jessilyn M. Froelich and senior author Yael I. Nillni, recruited 161 pregnant women initiating prenatal care before 28 weeks of gestation at a large safety net hospital in the northeastern United States. The setting matters: safety net hospitals serve populations that often carry a heavier burden of trauma and economic hardship, and postpartum depression is known to strike women from low-income and marginalized backgrounds at elevated rates. Between March 2018 and October 2020, more than 1,300 patients were approached, and the 161 who enrolled completed a baseline psychiatric evaluation before 29 weeks of gestation, followed by three additional assessments during pregnancy and one final visit between five and seven weeks after delivery. At each time point, the women rated their insomnia severity using the Insomnia Severity Index, a validated seven-item questionnaire covering difficulty falling asleep, staying asleep, waking too early, and the daytime distress that poor sleep inflicts.

What set this study apart from earlier work was the rigor of its psychiatric classification. Rather than simply asking women whether they had experienced trauma, the researchers conducted full structured clinical interviews using the Clinician-Administered PTSD Scale for DSM-5 and the Structured Clinical Interview for DSM-5. This allowed them to sort participants into four groups: trauma-exposed women with PTSD, trauma-exposed women with another mental health condition but not PTSD, trauma-exposed women with no current mental health diagnosis, and women with neither trauma exposure nor any current psychiatric condition. The results of that sorting were sobering. More than 83 percent of the sample had experienced at least one potentially traumatic event, 13.2 percent met criteria for PTSD, and another 27.8 percent carried a current mental health diagnosis such as major depressive disorder, substance use disorder, or premenstrual dysphoric disorder.

To trace how sleep changed over time, the team turned to a statistical technique called growth mixture modeling. Unlike conventional approaches that average outcomes across an entire sample, growth mixture modeling searches for hidden subgroups of individuals whose symptoms follow different mathematical curves. The researchers modeled Insomnia Severity Index scores across four pregnancy time points, treating gestational age as a continuous variable with linear growth, and estimated random intercepts and slopes so that each woman could deviate from her group’s average starting point and rate of change. They then compared models containing one, two, three, and four latent classes using the Akaike and Bayesian Information Criteria. The two-class solution won out on parsimony and fit, and it revealed a split the researchers had not fully anticipated.

Roughly 71.5 percent of the women belonged to what the investigators labeled the Normative Sleep class. These participants started pregnancy with relatively low insomnia scores, averaging around 7.2 on the index, and their symptoms drifted slightly, though not significantly, downward over the following months. The remaining 28.5 percent followed a far more troubling course. This Poor Sleep class began pregnancy with subthreshold insomnia, averaging 12.4 points, and then climbed steadily, gaining about 1.55 points per unit of time, until reaching a clinically significant average of 17.1 points by the final weeks of gestation, a level consistent with moderate insomnia. The researchers had hypothesized a third trajectory of consistently poor sleep, but the data told a different story: for a substantial minority of pregnant women, sleep does not merely stay bad, it actively worsens as the body approaches delivery.

The psychiatric groups predicted who landed on which curve. Compared with healthy participants, women with trauma exposure and PTSD had nearly nine times the odds of belonging to the Poor Sleep class, an odds ratio of 8.97 that was statistically significant. Trauma-exposed women with another current mental health condition but no PTSD also faced markedly elevated odds, at 4.07. But here was the study’s most intriguing nuance: women who had experienced trauma yet carried no current psychiatric diagnosis did not differ significantly from trauma-free women, with a non-significant odds ratio of 2.05. Trauma exposure alone, in other words, did not doom a woman to poor sleep. It was the psychological sequelae of trauma, the PTSD, the depression, the anxiety, that set the worsening trajectory in motion. This finding challenges any simplistic view of trauma as a binary risk factor and points instead to underlying vulnerabilities that trauma and psychopathology share.

The link to postpartum depression was equally compelling. When the researchers examined Edinburgh Postnatal Depression Scale scores at the five-to-seven-week postpartum visit, membership in the Poor Sleep class explained roughly 19 percent of the variance in depressive symptoms. Women in the Poor Sleep class averaged 9.26 points on the scale, compared with 4.68 points for the Normative Sleep class, a difference of 4.58 points that was highly significant. While 9.26 falls below the traditional cutoff of 13 for probable postpartum depression, it sits in the range associated with mild depressive symptoms under more flexible scoring interpretations, and it exceeds the threshold of 7 that many clinics use to trigger referral to specialized mental health care. The sleep trajectory, in effect, functioned as an early biomarker of emerging postpartum mood problems.

The biology behind these patterns is likely multifaceted. Sleep is fundamental to emotional regulation and stress reactivity, and insomnia is both a symptom of PTSD and a risk factor for its onset and persistence; between 60 and 90 percent of people with PTSD experience insomnia, and it frequently lingers even after successful PTSD treatment. Recent ecological momentary assessment research has shown that women with PTSD are especially sensitive to sleep loss, with a single bad night amplifying next-day PTSD symptoms. During pregnancy, shifting neuroendocrine signals, rising physical discomfort, and the sleep fragmentation that comes with a changing body may interact with these pre-existing vulnerabilities, creating mutually reinforcing cycles in which poor sleep deepens emotional dysregulation and emotional dysregulation further erodes sleep. Because the psychiatric diagnoses in this study predated the sleep assessments, the researchers are careful to note that causality cannot be established, but the temporal pattern, in which worsening sleep precedes elevated postpartum depressive symptoms, is consistent with the idea that sleep disturbance contributes to, rather than merely reflects, emerging depression.

The clinical implications are hard to ignore. Most pharmacological sleep aids must be used with caution or are outright contraindicated during pregnancy because of potential harm to the developing fetus, which leaves behavioral interventions as the safest option. Cognitive Behavioral Therapy for Insomnia has a strong evidence base in general populations, and the authors argue that integrating it into routine prenatal care could intercept worsening trajectories before they harden into postpartum illness. Because some women’s sleep deteriorates progressively rather than starting out badly, they recommend early and repeated screening for insomnia, trauma exposure, and mental health symptoms across all three trimesters, not just a single check at intake. The study does have limitations, including a modest sample of 151 women in the final analysis, the use of categorical diagnoses that may obscure the compounding effects of comorbidity, and the absence of data on discriminatory obstetric care experiences that can amplify both sleep problems and psychiatric risk. Still, the message is clear and urgent: the road to postpartum depression may be paved months in advance, one restless night at a time, and clinicians who watch a pregnant patient’s sleep closely may catch the danger while there is still time to change course.

Subject of Research: Longitudinal sleep trajectories during pregnancy and their associations with trauma exposure, PTSD, and postpartum depression

Article Title: Sleep trajectories in pregnancy: associations with trauma exposure, PTSD, and postpartum depression

Article References: Froelich, J. M., Stucchi, S. N., Thomas, J. L., Cesare, N., Rasmusson, A. M., Pineles, S. L., & Nillni, Y. I. (2026). Sleep trajectories in pregnancy: associations with trauma exposure, PTSD, and postpartum depression. Journal of Behavioral Medicine. https://doi.org/10.1007/s10865-026-00715-w

Image Credits: AI Generated

DOI: 10.1007/s10865-026-00715-w

Keywords: pregnancy, sleep trajectories, insomnia, PTSD, trauma exposure, postpartum depression, perinatal mental health, growth mixture modeling, prenatal care, CBT-I, maternal health, psychiatry