Preterm Birth for Some Women Linked to Specific Autoantibodies

A typical pregnancy lasts 40 weeks, but for about one in 10 pregnant women labor begins too soon, leading to preterm or premature birth, the leading cause of newborn deaths globally. Scientists at the University of California, San Francisco (UCSF) have identified specific antibodies that may trigger early labor. By analyzing maternal sera from term and preterm pregnancies, alongside studies in mice and human placental tissue, the researchers found elevated levels of these antibodies in women who delivered babies before 37 weeks' gestation.

The antibody in question, which targets a protein called IL1RA, blocks inflammation-related molecules that can cause uterine contractions. The UCSF team built a new immune profiling tool, phage immunoprecipitation sequencing (PhIP-seq), to detect these hidden immune signals. This tool revealed that women who experienced preterm labor exhibited broader antibody changes earlier in pregnancy compared to those who delivered at term.

The researchers also tested the effect of anti-IL1RA antibodies in pregnant mice, observing increased IL1β levels in the mothers' blood and placental damage, similar to human preterm deliveries. The findings suggest that IL1RA antibodies could potentially serve as a target for preventive interventions against preterm birth. However, the study acknowledges that only a fraction of preterm births involve these specific antibodies, indicating that multiple factors likely contribute to premature birth.