Your Immune System Starts Signalling Pregnancy…

Your Immune System Starts Signalling Pregnancy Complications From Week 9, Before You Even Know They're Coming Preeclampsia. Preterm birth. Fetal growth restriction. Gestational hypertension. These are among the most feared complications in obstetric care. And despite decades of research, our ability to predict and prevent them remains frustratingly limited. A new study from Erasmus MC, Rotterdam, published in Hypertension June 2026, may be pointing us toward something genuinely new: a molecular signal detectable in the first trimester, weeks before any clinical complication appears. Researchers followed 193 pregnant women from as early as 9 weeks of gestation, measuring how their immune antibodies, specifically IgG and IgA, changed their molecular structure across pregnancy. In a healthy pregnancy, these antibodies naturally shift toward an anti-inflammatory profile as gestation progresses. This is the immune system adapting to protect the developing baby.