Quantifying circulating hypoxia-induced RNA transcripts in maternal blood to determine in utero fetal hypoxic status.

Background: Hypoxia in utero can lead to stillbirth and severe perinatal injury. While current prenatal tests can identify fetuses that are hypoxic, none can determine the severity of hypoxia/acidemia. We hypothesized a hypoxic/acidemic fetus would up-regulate and release hypoxia-induced mRNA from the fetoplacental unit into the maternal circulation, where they can be sampled and quantified.

Quantifying mRNA coding growth genes in the maternal circulation to detect fetal growth restriction.

Objective: To examine whether mRNA circulating in maternal blood coding genes regulating fetal growth are differentially expressed in (1) severe preterm fetal growth restriction (FGR) and (2) at 28 weeks' gestation in pregnancies destined to develop FGR at term.

Study Design: mRNA coding growth genes were measured in 2 independent cohorts. The first was women diagnosed with severe preterm FGR (<34 weeks' gestation; n = 20) and gestation matched controls (n = 15), where the mRNA was measured in both maternal blood and placenta.

Placental specific mRNA in the maternal circulation are globally dysregulated in pregnancies complicated by fetal growth restriction.

Context: Fetal growth restriction (FGR) is a leading cause of perinatal mortality, yet no reliable screening test exists. Placental specific mRNA in the maternal circulation may reflect changes in the placental transcriptome in FGR and could be a novel biomarker for FGR.

Objective: The aim of the study was to identify placental specific RNA detectable in the maternal circulation and examine whether they are differentially expressed in severe preterm FGR.