title: Embryonic trunk circumference: a new biometric parameter for estimation of gestational age.
abstract: One hundred thirty-one uncomplicated, singleton pregnancies between 7 and 12 weeks of gestation were ultrasonically examined. Evaluation included confirmation of cardiac activity and measurements of fetal crown-rump length and trunk circumference. Both crown-rump length and trunk circumference were curvilinearly correlated with gestational age. A second- and third-degree polynomial equation best described this curvilinear relationship between trunk circumference and gestational age and between crown-rump length and gestational age. The crown-rump length and trunk circumference were similar in their prediction of gestational age, but the combination of the two parameters did not improve the prediction of gestational age. A nomogram of gestational age as predicted by trunk circumference was generated. These data provide an additional measurement for the estimation of gestational age in the first trimester of pregnancy.
mesh_terms: D001699:Biometry; D005260:Female; D005333:Fetus / Q000033:anatomy & histology*; D005865:Gestational Age; D006801:Humans; D011247:Pregnancy; D014463:Ultrasonography