Vaginal microbiota in the first trimester of pregnancy and the development of placental insufficiency

Fetal growth restriction and preeclampsia, the underlying pathogenesis of which is placental insufficiency, are among the leading causes of perinatal and maternal morbidity and mortality worldwide. Objective. To study the association between vaginal microbiome and placental protein levels in the first trimester of pregnancy with the risk of developing of placental insufficiency. Material and methods. The study included 283 patients without history of obstetrical, gynecologic, or medical conditions. Each patient had their placental protein levels assessed-human chorionic gonadotropin (hCG) and placental-associated plasma protein A (PAPP-A) — based on the initial screening, and their vaginal microbiota in the first trimester of pregnancy was analyzed using polymerase chain reaction. Depending on whether placental insufficiency subsequently developed, all patients were divided into two groups: Group 1 — 203 patients without placental insufficiency; Group 2 — 80 patients whose pregnancy was complicated by the development of placental insufficiency. Results. Patients of Group 2 had statistically significant lower concentrations of placental proteins — hCG and PAPP-A — as well as higher levels of Gardnerella vaginalis, Prevotella bivia, Porphyromonas spp., and Eubacterium spp. — were detected in the first trimester of pregnancy compared to those in Group 1. According to the study results, with a PAPP-A MoM level ≤0.486 based on the first prenatal screening data and the number of Sneathia spp., Leptotrichia spp., and Fusobacterium spp. bacteria, A vaginal microbiota with ≤107.3 DNA copies is associated with a high risk of developing placental insufficiency. Conclusion. Patients with reduced levels of placental proteins based on the initial prenatal screening and higher numbers of opportunistic microorganisms in the first trimester of pregnancy have a higher risk of developing placental insufficiency in late gestation. Timely correction of the vaginal microbiota during the preconception period and early pregnancy may be an important way to prevent placental insufficiency.