Timing and cause of perinatal mortality for small-for-gestational-age babies in South Africa: critical periods and challenges with detection

BACKGROUND Little information exists on timing and cause of death for small-for-gestational-age (SGA) babies in low-and-middle-income-countries (LMICs), despite evidence from high-income countries suggesting critical periods for SGA babies. This study explored the timing and cause of stillbirth and early neonatal mortality (END, <7 days) by small-for-gestational age in three provinces in South Africa. In South Africa, the largest category of perinatal deaths is unexplained stillbirth, of which up to one-quarter have intra-uterine growth restriction. METHODS Secondary analysis of the South African Perinatal Problems Identification Program (PPIP) database allowed for the analysis of gestational age at death and clinically confirmed diagnosis of stillbirth and early neonatal death (END) (>1000 g and >28 weeks) across gestation. Comparisons by province, size-for-gestational-age, gestational age groups, and maternal condition at death were performed. The provinces investigated were: Western Cape (fortnightly antenatal care visits from 32 to 38 weeks), Limpopo and Mpumalanga (no antenatal care visits between 32 to 38 weeks). RESULTS There were 528,727 births in the study period and 8111 stillbirths and 5792 early neonatal deaths. Similar timing of deaths across gestation was seen for the three provinces with the greatest proportion of deaths for SGA babies at 33-37 weeks (stillbirths 52.9 %; END 43.3 %; p < 0.05). SGA babies had a greater proportion of deaths due to hypertension (SGA22.9 %; AGA 18.6 %; LGA 18.6 %; p < 0.05) and intrauterine growth restriction (SGA 6.8 %; AGA 1.7 %; LGA 1.4 %; p < 0.05). No increase was seen in poor maternal condition for SGA babies and 54.9 % of deaths had a healthy mother. Of mothers that were healthy the greatest proportion of SGA stillbirths were due to unexplained intrauterine death (53.9 %). CONCLUSION There was a peak in stillbirths for SGA babies 33-37 weeks in all provinces. Detecting SGA is further complicated as in most cases the mother is healthy. Further research into Umbiflow Doppler velocimetry use in low-risk populations is warranted and may be a viable strategy to increase current detection of SGA babies at risk of mortality in LMICs.