Rachel's research goal is to improve maternal and child health through a deeper understanding of fetal growth. She is Professor of Human Genetics and a Wellcome Senior Research Fellow and leads a multidisciplinary research team. 

Her team has led studies that have identified more than 250 regions of the human genome where variations in the genetic code influence birth weight or placental weight. These studies have illuminated genetic links between early growth and later-life Type 2 diabetes. They have also provided insights into causal links between maternal characteristics and birth weight, and between fetal growth and adverse pregnancy outcomes. 

In 2019, Rachel was awarded the 15th international Joseph Hoet Research Award for excellence in the field of Diabetes and Pregnancy.