High altitude adaptation and pregnancy outcome study (HAPS): investigating the influence of hypoxia on birth weight (360G-Wellcome-109862_Z_15_Z)

A baby unable to grow to its full potential in the womb (intrauterine growth restriction, IUGR) results in low birth weight (LBW). Failure to adapt to a low-oxygen environment may impede placental growth and consequently, result in a LBW baby. LBW is especially common amongst newcomers to high altitude (HA) environments, however, populations with long HA residency are relatively protected, potentially through evolutionary selection of advantageous hypoxia related gene variants. Identification of such variants would implicate pathways involved in causing, or protecting from, IUGR. Researchers from the UK and India will collaborate to investigate this. We will recruit 300 pregnant women from a hospital situated at HA in Leh, India. Gene variants in the baby (the discovery cohort), associated with its birth weight, will be identified. We will then seek evidence of how these gene variants might affect growth: placental size and umbilical blood flow will be measured during pregnancy using ultrasound, and metabolic markers from the cord blood of newborn will be studied to see they are associated with significant gene variants. This work will inform further replication studies at HA and aid investigation of factors that play a role in causing IUGR/LBW at low altitude.