The cheek-to-cheek diameter in the ultrasonographic assessment of fetal growth.

Deviations from normal growth modify the amounts of adipose tissue and muscle mass in the adult and the fetus. As an index of the amount of adipose tissue in the fetus, the cheek-to-cheek diameter obtained on an ultrasonographic coronal view of the face at the level of the nostrils and lips was evaluated. Two hundred thirty-four singleton uncomplicated, well-dated pregnancies ranging from 20 to 41 weeks were studied. Two hundred fetuses with biometric measurements or estimated weights between the 10th and 90th percentile for gestational age were included in obtaining a nomogram. Cheek-to-cheek diameter as a function of gestational age was expressed by the regression equation: Cheek-to-cheek diameter (centimeters) = -0.908 + 0.195 Gestational age (gestational age greater than or equal to 20 weeks), with a Pearson correlation coefficient of R2 = 0.806. The cheek-to-cheek diameter/biparietal diameter ratio was almost constant, independent of gestational age, and ranged from 0.6 at 20 weeks to 0.7 at 41 weeks. Fetuses with intrauterine growth retardation tended to have lower ratios. Macrosomic fetuses of diabetic mothers had larger cheek-to-cheek diameters and elevated ratios, whereas large-for-gestational-age fetuses of nondiabetic mothers had normal ratios.