The value of middle cerebral artery to umbilical artery ratio by Doppler velocimetry in low risk postdate pregnancies

Abstract

Background and objective: Placental insufficiency is the primary cause of intrauterine growth restriction in normally formed fetuses and can be identified using middle cerebral artery to umbilical artery ratio Doppler velocimetry, and provide an estimate of downstream placental vascular resistance and placental blood flow. There is a strong association between reduced end-diastolic umbilical artery blood flow velocity and increased vascular resistance in umbilical placental microcirculation. Doppler ultrasound can assess the uteroplacental blood flow just before labor. This study aimed to investigate the use of the fetal cerebroumbilical ratio to predict the intrapartum fetal compromise in appropriately grown fetuses. Methods: A comparative cross-sectional study set at Sulaimania Maternity Teaching Hospital, Sulaimania, Iraq, from January to June 2015. The study recruited 121 cases, fetal biometry and Doppler indices were measured before established labor. The intrapartum and neonatal outcome details recorded. Results: Infants delivered by cesarean section for fetal compromise had significantly lower cerebroumbilical ratio than those born by spontaneous normal (none assisted) vaginal delivery and by cesarean section for other intrapartum causes. Infants with cerebroumbilical ratio 10th percentile. A cerebroumbilical ratio >90th percentile appears protective against cesarean section for fetal compromise. Amniotic fluid index of < 5 was associated with an increased cesarean section for fetal indication. Conclusion The cerebroumbilical ratio can identify fetuses at high risk of intrapartum fetal compromise. As a confounding variable, the amniotic fluid index was a useful tool for surveillance in prolonged pregnancy.

Keywords

• Cerebralumbilical ratio
• Amniotic fluid index
• Doppler
• Labour