OBJECTIVES: Our purpose was to investigate whether liver size is incre
ased in the fetuses of pregnant women with diabetes and whether there
is any relationship between fetal liver size and maternal glycemic cen
tral. STUDY DESIGN: Eighty pregnant women with diabetes had ultrasonog
raphic measurement of fetal liver length made at 18, 28, and 36 weeks'
gestation. Twenty-four obese, nondiabetic women were studied at 36 we
eks as controls. RESULTS: Fetal liver length measurements were signifi
cantly greater than normal by 18 weeks' gestation (12% above normal me
an values, p < 0.001) and increased further (19%, p < 0.02) by 36 week
s. In the obese controls liver length was increased 9% and was signifi
cantly lower than in the diabetic subjects (p < 0.001). CONCLUSIONS: F
etal liver size is increased in pregnant women with diabetes and canno
t be explained solely by maternal obesity. The major increase in liver
size occurs early in pregnancy but appears to be modifiable by glycem
ic control later in gestation.