AFJOG

REVIEW in high-risk pregnancies and its use has demonstrated a significant reduction in perinatal mortality. 23 Most studies assessing the clinical significance of the AEDF and REDF on the umbilical artery have been performed in high-risk populations and there is insufficient evidence for use of routine umbilical artery Doppler ultrasound in low-risk populations. 24 The advantage of Doppler ultrasound of the umbilical artery is that it is a test of function rather than of size and is able to detect poor placental function irrespective of the fetal growth centile with a single reading. 14 The Delphi consensus on defining FGR includes Doppler abnormalities in their definition. 25 A low-cost continuous wave Doppler device (Umbiflow™) has been developed by the Council for Scientific and Industrial Research (CSIR) and South African Medical Research Council (SAMRC) in SA. 26,27 Umbiflow™ is a mobile-connected Doppler device that uses a continuous- waveform to detect blood flow within the fetal umbilical cord. It consists of a handheld Doppler probe (transducer) with a universal serial bus (USB) cable that connects to any windows-based notebook on which the necessary Umbiflow™ software is installed. 26 Umbiflow™ measures the RI in the umbilical cord and plots it against the estimated gestational age to identify the fetus at risk for FGR. It also has the option of an integrated 3G card to facilitate a mobile internet connection and the automatic upload of Doppler results to a central server for remote expert support and electronic health record management. 26,27 The accuracy of the Umbiflow™ system in measuring the RI in the fetal umbilical artery has already been proven to be comparable to the commercial standard unit “gold standard”. 26,27,28 A critical advantage of the device is that it facilitates task- sharing of Doppler ultrasound screening to non-specialists and has the potential to substantially increase coverage to women receiving care in peripheral and rural health facilities. 27 Studies have demonstrated that the Umbiflow™ can be operated by nurses and midwives at the primary healthcare centres. 26,27,28 The device has a short learning curve empowering primary healthcare givers and non- specialist providers. 27,28 The use of Umbiflow™ has been shown to prevent unnecessary referrals to secondary level of care without increasing morbidity and has the potential to identify pregnant women at risk of poor perinatal outcome. 27 Continuous wave Doppler outcomes Three population-based studies using Umbiflow™ have recently been performed in SA. 28,29,30 All three studies screened women classified as having low-risk pregnancies between 28-34 weeks’ gestation and found similar prevalence’s of abnormal RI and AEDF of approximately 10% and 1% respectively in SA. Importantly, the prevalence of AEDF is about ten times that reported in other countries, especially the high-income countries. The Hlongwane et al. 29 , study explored fetuses that had AEDF and compared women with fetuses with AEDF to women attending the same clinics who had normal RIs. The AEDF group had amean birthweight of 2106 grams (±656.4) and 3099. 6 grams (±500.9) in the normal RI group. The AEDF group had significantly more low birthweight babies (71.8%), more SGA neonates (64.4%) and more preterm deliveries (mean GA at delivery 35.6 weeks [SD 3.1]). Of the neonates with AEDF, 38.6% required admission to the neonatal unit. Baseline characteristics for these women are presented in supplementary Table 1 and 2. The perinatal mortality rate was 91.9/1000 births compared to 9.9/1000 births in the normal RI group. One of the AEDF stillborn neonate had congenital abnormalities of the cardiopulmonary system. Important to note, all these women with AEDF at the time of screening were attending primary healthcare clinics and thought to be healthy, thus the test was detecting a high-risk fetus in a low-risk mother. Unfortunately, in both the Nkosi et al. 28 , and Hlongwane et al. 29 studies some women, whose fetuses had AEDF, declined further management. In the case of Hlongwane et al., 4 of the 5 women declining treatment delivered macerated stillbirths (see supplementary table 2) and in Nkosi et al., 3 of 4 women declining treatment had macerated stillbirths. The natural history of AEDF in the third trimester appears to be a stillbirth. Importantly, there was no increase in the neonatal deaths in both studies, so preventing stillbirths did not transfer potential stillbirths to neonatal deaths. If the women who declined treatment and the fetus with the congenital abnormality are removed from the outcomes of the AEDF group, the perinatal mortality is 35.7/1000 births. This is far lower than the perinatal mortality described in the literature of around 500/1000 births. 31 Two studies have looked at the impact of screening women classified as having low-risk pregnancies in SA, where screening in total just under 10 000 women has been performed. 28,32 A standard protocol was followed for all women whose fetuses demonstrated an abnormal RI. The protocol is described in detail elsewhere 28, 32 but includes referral to a high-risk clinic, full fetal assessment using imaging ultrasound, and admission, fetal monitoring, and corticosteroids where necessary. In both studies there was a significant reduction in stillbirths when comparing the screened group to women from the same area, same primary healthcare clinics and more than 28 weeks’ pregnant who did not have the Umbiflow™ screening. (Hlongwane et al. found a SBR 10.1/1000 births in the screened population and 17.8/1000 births in the unscreened group 32 (RR 0.57, 95% CI 0.29–0.85), and in Nkosi et al.,28 the perinatal mortality rate in the Umbiflow™ screened group was 11.4/1000 births and in the unscreened group was 21.3/1000 births (RR 0.58, 95% CI 0.42 - 0.81). It appears that screening with Umbiflow™ and adhering to the standard protocol of further management is associated with a step change reduction in stillbirths. AEDF is an indication of end stage placental disease associated with placental insufficiency and severe FGR so undetected FGR is probably a major cause of stillbirth in SA. Given the poor performance of SA with respect to its stillbirth rate compared to other similar countries, and the demonstrated inability to detect FGR antenatally with current methods, screening with Umbiflow™ might be of value if it is associated with a reduction in stillbirths. The final question is whether screening with Umbiflow™ is scalable to primary healthcare clinics. A costing analysis was performed by Rossouw et al., 33 who found that compared to estimates of cost and impact of scaling up interventions to save lives of mothers and children in SA 34 , the Umbiflow™ is more cost-effective than scaling up clean-birth practices, immediate assessment and stimulation during childbirth, breastfeeding promotion, appropriate complementary feeding, the hygienic disposal of children’s stools, the DPT, Pneumococcal, Rotavirus or Measles vaccines, therapeutic feeding (for severe wasting), and antiretroviral treatment. African Journal of Obstetrics and Gynaecology | Volume 1 | Issue 1 | 2023 | 06