Abstract:
Background, hypotheses and aims. Standard ultrasound biometry charts are derived from a European population. It is known that there is a difference in birthweight in babies born to mothers of different ethnic groups. The aim was to evaluate the rate of growth in fetuses from different maternal ethnic groups using standard and novel ultrasound biometry measurements in normal pregnancy. The hypotheses are that: 1. fetal growth in different ethnic groups is characterised by different growth patterns of skeletal and soft tissue biometry. 2. the difference in fetal growth between these ethnic groups is due to maternal anthropomorphic characteristics. Methods This was a longitudinal observational ultrasound study. Participants were healthy pregnant women whose primary ethnicity was European (NZE), Māori, Pacific Island or Indian. Only pregnancies with normal outcomes were included. Each participant was scanned at 4 weekly intervals from between 16 and 18 weeks to delivery. Ultrasound measurements were Biparietal Diameter, Head Circumference, Humeral Diaphyseal Length, Abdominal Circumference and Femur Length. 3D ultrasound measurements were Thigh Circumference, partial Thigh Volume, Arm Circumference and partial Arm Volume. Neonatal measurements were birthweight, head circumference, crown-heel length and thigh circumference. Statistical analysis included multilevel linear mixed effects modelling, which accounts for correlation of longitudinal measurements. Results Maternal characteristics were similar, except for weight, between the ethnic groups.