Professor Lumbers is an internationally respected authority on fetal and maternal physiology. Her original discovery that blood and amniotic fluid contain an inactive form of renin is a landmark in the understanding of the renin-angiotensin system of hormones that contribute powerfully to blood pressure regulation. Her finding that oestrogens in contraceptive pills increase renin substrate production is fundamental for understanding blood pressure regulation in women. Her many original and important experiments have shown the widespread involvement of the angiotensin system in pregnancy, in control of maternal and fetal blood pressure, and in regulation offetal renal function.