Diverse maternal and fetal pathology associated with absent diastolic flow in the umbilical artery of high-risk fetuses.

Twenty-two of approximately 450 high-risk pregnancies referred to a regional center for a level II sonographic examination after 20 weeks' gestation were characterized by absent or reversed diastolic flow in the umbilical artery. Ten fetuses had congenital malformations or were aneuploid. Ten were growth-retarded in association with other problems: maternal hypertension, preeclampsia, cyanotic heart disease, elevated maternal serum alpha-fetoprotein levels, or twin gestation. In two cases, no etiology could be identified. Knowledge of the fetal karyotype, fetal anatomy, gestational age, maternal disease, and fetal status as determined by other tests of fetal well-being was required to optimize outcome in each case. In view of the heterogeneous etiologies of absent or reversed diastolic flow, management of such cases must be individualized.