Symphysis-Fundus Height and Pregnancy Characteristics in Ultrasound-Dated Pregnancies

In Brief Objective To investigate the relation between maternal and pregnancy characteristics and symphysis-fundus height values at term in an obstetric population dated by sonography. Methods Three hundred twenty-five women were recruited from the antenatal clinics of the Queen's Medical Centre, Nottingham, United Kingdom for measurement of fundal height and for ultrasound scans. Symphysis-fundus height measurements were analyzed by multivariate regression analysis in relation to gestational age, maternal height and weight, ethnic group, and smoking. Results Gestational age and maternal characteristics explained nearly half of the variability in symphysis-fundus height. Gestational age was the most important determinant, followed by maternal weight, parity, and sex of the infant. The other variables were not significantly correlated. Conclusion Maternal characteristics had statistically significant effects on the expected symphysis-fundus height, which suggests that individually adjusted fundal height charts may improve the precision of clinical screening for fetal growth restriction. Gestational age, maternal weight, parity, and fetal sex explain half of the variability in symphysis-fundus height measurements.