Identifying the high-risk fetus in the low-risk mother using fetal Doppler screening

Abstract

Identifying the high-risk fetus in the low-risk pregnant mother (LRM) is a neglected area of research. Fetal growth restriction (FGR) is a major cause of stillbirths, especially in low- and middle-income countries (LMICs). FGR is very poorly detected particularly in healthy pregnant women classified as low risk. Umbiflow is an inexpensive continuous-wave Doppler ultrasound (CWDU) apparatus that is suitable for use by low-level health care providers for screening low-risk pregnant populations. It can easily detect umbilical artery blood flow in the cord, which correlates well with placental function, and poor placental function correlates well with FGR. Use of CWDU to screen an LMIC population of more than 7,000 LRMs has demonstrated a high prevalence of abnormal umbilical artery flow of 13%, and absent end-diastolic flow, which is associated with end-stage placental disease, was found in 1.2%. This is 10 times higher than previously reported in high-income countries. Screening with CWDU together with a standard protocol managing those pregnancies with abnormal placental blood flow resulted in a 43% reduction in stillbirths (risk ratio: 0.57; 95% confidence interval= 0.29, 0.85) in this LRM population. Further, follow-up of infants who had abnormal umbilical artery blood flow showed that these infants had significantly less fat-free mass at ages 6 weeks, 10 weeks, 14 weeks, and 6 months, than those with normal umbilical artery blood flow (P<.015), confirming that CWDU was able to detect true FGR. Thus, screening with CWDU can detect the fetus at risk of stillbirth, and infants likely to have suboptimal growth and development postnatally. Screening with CWDU in LRMs opens the door to a step change in preventing stillbirths in LMICs.