Prenatal detection of ischemic changes in the placenta of the growth-retarded fetus by Doppler flow velocimetry of the maternal uterine artery.

OBJECTIVE

To determine the relationships among the pregnancy outcomes of growth-retarded fetuses, Doppler flow velocimetry of the fetomaternal circulation, and pathologic changes in the placenta.

METHODS

Forty-seven fetuses confirmed to be growth-retarded by ultrasonographic biometry were monitored during pregnancy in terms of the resistance indexes of the maternal uterine, fetal umbilical, and fetal middle cerebral arteries. After delivery, the placentas were examined for pathologic changes such as infarction and villous ischemia.

RESULTS

Compared with 23 fetuses with nonischemic placentas, 24 growth-retarded fetuses whose placentas showed ischemic lesions were more frequently delivered preterm (P < .001) and by cesarean for fetal distress (P < .01), and they also had lower mean pH, higher carbon dioxide pressure, and lower oxygen pressure values (P < .05). Compared with the fetal umbilical and middle cerebral artery resistance indexes, the uterine artery resistance index showed the highest sensitivity (91.7%), specificity (78.3%), and positive predictive value (81.5%) for detecting placental ischemic changes. Linear discriminative analysis also showed that the uterine artery resistance index had the strongest correlation (P < .00001) with the placental ischemic changes.

CONCLUSIONS

Ischemia of the placenta is associated with an adverse pregnancy outcome in growth-retarded fetuses. The placental ischemic changes can be detected using Doppler flow velocimetry. Measurement of the uterine artery resistance index might be useful for determining the clinical management of growth-retarded fetuses.