High altitude adaptation and pregnancy outcome study (HAPS): investigating the influence of hypoxia on birth weight

Intrauterine growth restriction (IUGR) results in babies being born with a low birth weight. Failure to adapt to a low-oxygen environment may impede placental growth and consequently, result in a low birth weight. LBW is especially common among newcomers to high altitude environments. People who have lived in high altitudes for a long time have some protection, potentially through evolutionary selection of advantageous hypoxia-related gene variants. If such variants could be identified, pathways that cause or protect from IUGR could be put in place. Researchers from the UK and India will collaborate to investigate this.

We will recruit 300 pregnant women from a hospital in Leh, India, which is in a high altitude area. Gene variants in babies associated with birth weight, will be identified. We will then seek evidence of how these gene variants might affect growth by measuring placental size and umbilical blood flow during pregnancy using ultrasound, and recording metabolic markers from the cord blood when the baby is born to see if they are associated with significant gene variants.

This work will inform further replication studies at high altitude and aid investigation of factors that play a role in causing IUGR/LBW at low altitude.