Childhood Poverty Alters Immune System Function in Pregnant Women

Article

Regardless of their current economic status, women born into poverty show higher levels of immune responsiveness during pregnancy, according to new research. These findings suggest a possible mechanism by which health disparities persist across generations.

Ann E.B. Borders, MD, of the NorthShore University HealthSystem in Chicago, IL, presented results from the prospective study at the 37th Annual Pregnancy Meeting of the Society for Maternal Fetal Medicine held January 23 to 28, 2017, in Las Vegas, NV. Douglas Williamson, PhD, of the Department of Psychiatry and Behavioral Sciences at Duke University, was a coinvestigator of the study.

Poverty is a known risk factor for poor health outcomes. A growing body of evidence also suggests that the adverse effects of poverty during childhood can last for generations, even after an individual’s socioeconomic status has improved.

The study was designed to evaluate the potential link between maternal childhood poverty and immune system function during pregnancy. In total, 128 pregnant women were recruited from a prenatal clinic in Pittsburgh, PA, to participate in the study.

Women treated with progesterone after 14 weeks of pregnancy were excluded from the analysis. Pregnancies with major fetal congenital anomalies and known chromosomal abnormalities were also excluded.

The median age of participants was 30.4 years (Table). All of the women included in the study had a singleton pregnancy.

Table. Baseline Characteristics

Characteristic Study Participants
(N = 128)
Mean patient age, y 30.4
Race/ethnicity, %
Non-Hispanic white 78.5
Non-Hispanic black 16.9
Other 4.2
Education, %
Some high school or less 15.4
Some college/associate’s degree 26.9
Bachelor’s degree or higher 57.7
Annual income, $ (%)
< 15,000 9.2
15,000-50,000 24.6
> 50,000-100,000 39.2
> 100,000 25.4
Mean gestational age at clinic visits, wk
Second trimester 16.8
Third trimester 33.3

The first step in the study was to determine whether the participants were exposed to economic disadvantages during childhood. All patients completed an 8-item questionnaire designed to assess the presence and severity of childhood hardship. The questionnaire assigned 1 point to each response indicating an economic disadvantage during childhood, such as receiving public assistance or not having access to medical care when needed. Based on total scores, participants were then categorized into group 1 (≤ 1 disadvantage) or group 2 (≥ 2 disadvantages).

The researchers then measured the degree of immune responsiveness among pregnant women by focusing on interleukin (IL) 6 response. Study participants attended 2 follow-up clinic visits during the second and third trimesters of pregnancy, respectively, for venous blood collection. The blood samples were subjected to a standard lipopolysaccharide (LPS) challenge to evaluate leukocyte stimulation and innate immune activation. The blood samples were co-incubated with LPS for 12 hours, after which IL-6 concentrations were measured.

The primary end point of the study was the interaction between childhood disadvantage and stimulated immune response. Complete data on IL-6 levels at both time points were available for 123 women. Of these, 28 (23%) were classified as having experienced economic disadvantages in childhood.

The results showed a significant interaction between childhood disadvantage and immune/inflammatory responses over the course of pregnancy. Compared with the women in group 1, women in group 2 had significantly higher IL-6 levels in response to LPS stimulation at both the second and third trimester time points (P = .001).

The researchers found that the relationship between childhood disadvantage and immune responsiveness was significant even after controlling for current maternal socioeconomic status, maternal stress during pregnancy, maternal body mass index prior to pregnancy, and other obstetric risk conditions.

These findings highlight the complexity of poverty as a risk factor for individuals born into poverty, as well as the next generation. “Childhood poverty is driving an altered inflammatory status during pregnancy,” commented Borders.

“We need to think about the high prevalence of childhood poverty in this country and whether there are interventions that can alter adverse health outcomes,” she said.

Source: Entringer S, Borders A, Buss C, et al. Economic hardship during childhood is associated with immune hyperresponsiveness during pregnancy. Presented at: Society for Maternal-Fetal Medicine 37th Annual Pregnancy Meeting; January 23-28, 2017; Las Vegas, NV. Abstract 626.