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New research suggests that pregnant women with a history of childhood maltreatment tend to show stronger inflammatory responses to a stressful laboratory task, and that these heightened responses are linked to more pregnancy and birth complications. The findings point to a possible biological pathway through which the effects of early adversity might carry into the next generation, though the study did not track children’s later development. The study was published in Developmental Psychobiology.
Inflammation is the immune system’s natural defense mechanism. When the body faces an injury, infection, or severe stress, it releases specific proteins called pro-inflammatory cytokines, which trigger swelling and direct immune cells to protect the affected area. During a typical pregnancy, a woman’s immune system naturally shifts toward an anti-inflammatory state during the second and third trimesters. This protective shift helps prevent the mother’s body from rejecting the developing fetus and supports a healthy, full-term pregnancy.
Sometimes this protective environment breaks down. According to toxic stress theory, severe or prolonged adversity early in life can lastingly alter how a person’s physiological systems respond to challenges. When a person faces a threat, the sympathetic nervous system activates the “fight or flight” response, which can set off a biological chain reaction that produces pro-inflammatory cytokines, such as interleukin 6, and other markers like C-reactive protein, a protein released during inflammation.
“We know negative health impacts of stress and adversity tend to carry across generations, and prenatal development represents a critical window for the mothers’ accumulated stress to shape their child’s future risk,” lead author Heidemarie K. Laurent, an associate professor of human development and family studies and Edna Bennett Pierce Professor of Care and Compassion at Pennsylvania State University, told PsyPost. “However, we still don’t know enough about the nature of these risk paths—that is, how early life adversity shapes women’s stress responsiveness in pregnancy, and how these stress responses may go on to create complications in pregnancy and/or childbirth that harm child development.”
Past research suggests that early adversity is linked to differences in biological stress responses. For instance, a study covered by PsyPost in 2025 found that women who identified childhood trauma as their most stressful life experience exhibited blunted responses of cortisol, a stress hormone, to acute psychosocial stress.
Previous studies measuring inflammation in pregnant women with trauma histories have yielded mixed results, and the authors suggest one reason may be that many measured resting inflammation rather than how the body reacts to a specific stressor. For example, a 2020 study found that adults who reported childhood physical neglect showed exaggerated inflammatory responses after a stressful public speaking and math task. To capture these acute reactions, researchers have increasingly turned to collecting saliva, which provides a non-invasive way to track brief spikes in inflammation.
While oral inflammation is localized to the mouth, it may signal broader systemic health risks during pregnancy. For example, a 2024 review suggested that oral inflammatory conditions, such as periodontal disease (gum disease), are associated with a higher rate of premature births and preeclampsia (a dangerous high-blood-pressure condition in pregnancy).
To investigate this further, Laurent and her colleagues aimed to determine whether early adversity changes a pregnant woman’s salivary inflammatory response to an acute stressor. The researchers recruited 158 pregnant women from local health centers, community agencies, and social media advertising. Most were in their third trimester, with an average gestational age of about 31 weeks. The women first completed a questionnaire assessing their history of childhood maltreatment, rating how often they experienced emotional neglect, physical neglect, physical abuse, sexual abuse, and emotional abuse.
To measure their physical response to stress, the participants completed a standardized psychological challenge known as the Trier Social Stress Test. Following a brief preparation period, the women delivered a five-minute speech and then performed five minutes of mental arithmetic out loud in front of a trained evaluator. The researchers collected five saliva samples from each participant over the course of the session, starting before the task and ending almost an hour afterward. These samples were tested for the presence of C-reactive protein and three pro-inflammatory cytokines: interleukin 1 beta, interleukin 6, and tumor necrosis factor alpha.
Roughly three months after giving birth, 112 of the original participants returned to report on their obstetric outcomes. Their reported pregnancy complications included medical problems such as gestational diabetes and high blood pressure, but also anxiety and depression during pregnancy, which were the two most commonly reported items. They also reported on birth complications, including whether the baby required oxygen, an incubator, or a stay in the neonatal intensive care unit. Additional data was collected on the baby’s birth weight and whether the birth was premature.
The scientists found that a history of childhood maltreatment predicted higher and more prolonged inflammatory responses to the stress test. Physical neglect and sexual abuse had the most widespread associations with the women’s immune reactions. About 13 percent of the sample reported moderate to severe physical neglect, and 10 percent reported moderate to severe sexual abuse. Women reporting more physical neglect tended to show both higher levels of inflammatory proteins after the stressor and a more prolonged rise, while those reporting more sexual abuse showed higher levels, though the authors note these effects were small.
Separately, these exaggerated inflammatory responses were associated with more challenging obstetric outcomes. Across all analyses, the researchers noted that the findings remained similar even after accounting for factors such as current medications, educational level, and marital status. Women who displayed higher levels of inflammatory cytokines during the prenatal stressor reported a greater total number of pregnancy complications. Women whose inflammatory responses continued to rise over the course of the testing session tended to report poorer birth outcomes.
An extended inflammatory response was associated with a greater likelihood of premature birth, defined as birth before 37 weeks of gestation, which occurred in 4 percent of the sample, or only about four or five births, so this finding rests on very few cases. Inflammatory responses were not linked to birth weight.
“This suggests stress-induced inflammation in pregnancy may serve as a target to interrupt intergenerational health risk cascades,” Laurent explained. “A practical implication is that women who screen positive for maltreatment history during prenatal care could be provided behavioral and/or pharmaceutical supports to reduce inflammation and improve long-term mother/child health.”
The findings align with research covered by PsyPost in 2025, which also linked maternal inflammation during pregnancy to shorter gestation and preterm birth. That earlier study, however, measured resting systemic inflammation in blood rather than salivary inflammatory reactivity to an acute stress test.
As with all research, there are some caveats to consider. The sample was largely composed of middle-to-upper-income white women who were prescreened for relatively low-risk pregnancies. This means the findings might not fully generalize to populations facing higher rates of poverty or specialized medical risks. The study also relied on self-reported, retrospective accounts of childhood maltreatment and birth complications, which can be influenced by memory biases.
The study also did not formally test whether inflammation explains the link between childhood maltreatment and obstetric complications; a preliminary test of that pathway did not reach statistical significance. Nor did it test whether reducing inflammation improves outcomes. Women who didn’t return for follow-up were younger, less educated, and less likely to be married, and since these traits are linked to higher inflammation, the dropouts may have weakened the results. There is also ongoing debate among scientists regarding the exact relationship between localized salivary inflammation and body-wide systemic inflammation.
“A caveat to keep in mind is that to get repeated measures of acute response to social stress, we tested inflammation in saliva rather than blood or other tissues,” Laurent noted. “Although we have growing evidence that oral inflammation relates to health-related risks, we do not know for sure the extent to which this represents systemic inflammation or inflammation in the placenta that may more directly influence fetal development.”
The authors also note that tracking these markers in both blood and saliva throughout the entire pregnancy, rather than just the third trimester, would provide a more complete picture. Using actual medical records instead of self-reports in future studies would also help confirm the exact nature of the birth complications.
“A next step I hope to pursue based on this research is to investigate effects of prenatal mindfulness training on pregnant people’s stress-induced and placental inflammation, and how these markers of inflammation predict birth outcomes,” Laurent said. “This would help to solidify our knowledge of when and how we can best intervene to disrupt risk paths and improve intergenerational health.”
The study, “Inflammatory Stress Response During Pregnancy as a Connecting Link in Intergenerational Risk Cascades,” was authored by Heidemarie K. Laurent, Sherryl H. Goodman, Karen D. Rudolph, Kento Suzuki, Penina Backer, Aastha Dhimal, Sarah Pikhit, and Douglas A. Granger.