AFJOG

REVIEW THE BURDEN OF STILLBIRTHS Stillbirths reflect care during the third trimester and the intrapartum period. 1 Stillbirths are virtually invisible to the public and most healthcare professionals. As such they are neglected to the great detriment of the families concerned. 2 However, stillbirths remain high, 2.0 million stillbirths occurred worldwide. 2 Ninety-eight percent occur in low and middle-income countries (LMIC). 2 South Africa (SA) is classified as an upper middle-income country, with respect to the stillbirth rate we perform very poorly, ranking 50th of 54 countries and 6th of 7 in Africa 2 compared to similarly classified countries. 2 SA has about 20 000 stillbirths per year and more than twice as many stillbirths as neonatal deaths for babies over one kilogram. 3 Contrary to perceived wisdom SA has far more antenatal stillbirths compared to intrapartum stillbirths (66% macerated versus, alive on admission 10% and dead-on admission 22% (unknown 2%). 3 Stillbirths classified as unexplained are 46% more common than intrapartum and neonatal deaths due to intrapartum asphyxia and birth trauma combined. 4 The most common causes of antenatal stillbirths are unexplained stillbirths, hypertensive disorders of pregnancy (HDP) and abruptio placentae. 5 Prevention of stillbirths thus needs to focus on antenatal prevention targeting these issues. Preventing the deaths due to HDP has been relatively straight forward. Local and global data showed an increased risk in perinatal mortality associated with reduced focused antenatal contact model. 5,6 The new antenatal policy of Basic Antenatal Care Plus (BANC Plus) increased contacts and its implementation has led to an increased detection of HDP and subsequent reduction in stillbirths due to HDP. 1,7,8 The major issue is tackling the issue of unexplained stillbirths. The majority (53.9-59.8%) of stillbirths in SA are classified as unexplained. 3,5,9 Most occur in women regarded as having low-risk pregnancies and undiagnosed small for gestational age (SGA) babies is common in this group. 10 Mahdi et al. 11 demonstrated placental insufficiency and infection are major causes of stillbirths in SA. Placental insufficiency leads to fetal growth restriction (FGR) and SGA babies are often growth restricted thus FGR might be a major cause of the unexplained stillbirths. Currently, there are no effective clinical tools that detect FGR. Routine clinical methods to detect poor fetal growth (palpation or symphysis fundal height) are ineffective and have not shown effect on the rate of stillbirths or perinatal mortality. 12 Fetal movement counting has also been found to be ineffective. 13 Detection of the fetuses that are at risk of growth restriction thus remains a challenge due to the subjectivity of the current available antenatal fetal growth monitoring tools particularly in LMIC. 14 As many as three quarters of babies with FGR are not recognised as such before delivery. 15 In a low-risk pregnancy with a lower threshold of suspicion the detection rate is even lower, at approximately 15%. 16 The WHO recommendations suggest that all pregnant women should receive an imaging ultrasound to determine or confirm the gestational age. 17 It was hoped that routine imaging ultrasound would be an effective method in helping to detect FGR. However, recently a two-stage routine conventional ultrasound in low-income countries was shown to have no effect on perinatal or maternal death or on antenatal attendance. 18 Umbilical artery Doppler as an intervention Doppler ultrasound of the umbilical artery measures the fetal blood flow through the placenta. Poor fetal blood flow through the placenta leads to ineffective transfer of nutrients and oxygen and correlates well with placental function. It is a measure of placental insufficiency and thus correlates well with FGR. 19 Doppler ultrasound technique uses Doppler principles, where high frequency sound waves bounce off circulating red blood cells and the reflection of the sound wave is measured as a shift in frequency. The direction of the blood flow and velocity is calculated. 19 Continuous wave Doppler ultrasound sends a continuous stream of sound waves and reflects any movement through which the sound passes. The umbilical cord is surrounded by amniotic fluid so this creates a sound wave through which the classic signature of the umbilical artery (pulsatile) and umbilical vein (not pulsatile and flowing in the opposite direction) can be observed. This means no imaging ultrasound is necessary to identify the vessel which makes the device considerably less expensive than imaging ultrasound. Pulsed wave Doppler ultrasound is somewhat different in that pulses of waves are sent and by using a range gate and imaging ultrasound different vessels can be identified and studied. This however, makes for a considerably more complex and expensive machine. The umbilical artery Doppler resistance index (peak systolic- end diastolic/peak systolic) decreases with increasing gestational age as the resistance in the tertiary arterioles of the placenta open. 19 Placental insufficiency usually results in a decrease in placental blood flow due to obliteration of the tertiary arterioles and is reflected as a fall in the end diastolic flow and thus a rise in resistance index (RI). 19 This rise in RI is associated with FGR and once absent end diastolic flow (AEDF) (RI=1; end diastolic flow=0) or reversed end diastolic flow (REDF) is detected there is end stage placental disease and is associated with severe adverse perinatal outcomes. 20 AEDF is associated with FGR, neuro-developmental sequelae, chromosomal, structural anomalies and increased perinatal deaths. 21,22 Umbilical artery Doppler ultrasound has been well studied TMAG Hlongwane 1 , RC Pattinson 1 1 Department of Obstetrics and Gynaecology, University of Pretoria, Pretoria, South Africa 1 Research Centre for Maternal, Fetal, Newborn & Child Health Care Strategies, University of Pretoria, Pretoria, South Africa 1 Maternal and Infant Health Care Strategies Research Unit, South African Medical Research Council, Pretoria, South Africa CORRESPONDENCE: TMAG Hlongwane| Email: Tsakane.hlongwane@up.ac.za Time to re-think prevention of stillbirths in South Africa? African Journal of Obstetrics and Gynaecology | Volume 1 | Issue 1 | 2023 | 05