Objective An adverse fetal environment may lead to smaller kidneys and subsequently renal disease and hypertension in adulthood. The aims of this study were to examine whether kidney size tracks from fetal life to childhood and to examine whether maternal and fetal characteristics are associated with kidney size at the age of 2 years.
Methods The study was conducted in 688 infants participating in a prospective cohort study from early fetal life onwards. Maternal characteristics were measured in early pregnancy. Fetal growth and placental characteristics were assessed in second and third trimester. Kidney size was measured in third trimester of pregnancy and at the postnatal ages of 6 and 24 months.
Results Children tended to remain in the lowest and highest quartiles of kidney volume from third trimester to the age of 2 years (OR 2.05 (95% CI: 1.38 to 3.06) and 3.29 (95% CI: 2.22 to 4.87)). Maternal height and pre-pregnancy weight were positively associated with kidney volume at the age of 2 years. Third trimester fetal head circumference, abdominal circumference and estimated weight and postnatal length were positively associated with kidney volume at 2 years of age. Preferential fetal blood flow to the brain was associated with smaller kidneys.
Conclusions Small kidney size in fetal life tends to persist in childhood. Maternal anthropometrics and fetal biometrics and blood flow patterns are associated with kidney size in childhood. Follow-up studies are needed to examine whether these variations in kidney size are related to renal function and blood pressure in later life.