Interferon epsilon and preterm birth subtypes; a new piece of the type I interferon puzzle during pregnancy?

Problem: Interferon epsilon (IFNε) is a unique type I IFN that is expressed in response to sex steroids. Studies suggest that type I IFNs regulate inflammation-induced preterm birth (PTB), but no study has examined the role of IFNε in human pregnancy. Method of Study: We used stored vaginal swabs between 8 and 26 weeks of gestation from the Global Alliance to Prevent Prematurity and Stillbirth (GAPPS) biobank and measured IFNε by enzyme-linked immunosorbent assay (ELISA). A total of 29 women with spontaneous preterm births, 34 women with medically indicated preterm births, and 134 women with term births were included. Secondary outcomes included a preterm birth with chorioamnionitis and preeclampsia with a preterm birth. Logistic regression calculated odds ratios (OR) and 95% confidence intervals (CI) adjusting for maternal age, race, body mass index, prior pregnancy complications, lower genital tract infections, chronic health conditions, and gestational age at blood draw. Results and Conclusions: There was no significant association between IFNε and spontaneous preterm birth (OR_adj 1.0, 0.8–1.3) or chorioamnionitis (OR_adj 1.6, 0.7–3.5). A trend toward increased odds of medically indicated preterm birth (OR_adj. 1.3, 1.0–1.8) was observed. This was likely due to elevated IFNε among women with preterm preeclampsia (OR_adj. 2.0, 95% CI 1.3–3.2). While exploratory, our novel findings suggest that larger longitudinal studies of IFNε across human pregnancy may be warranted.