The association between preterm labour, perinatal mortality and infant death (during the first year) in Bishop Lavis, Cape Town, South Africa

Abstract

Background: We present further analyses from the Safe Passage Study, where the effect of alcohol exposure during pregnancy on sudden infant death syndrome and stillbirth was investigated.

Objectives: To describe pregnancy and neonatal outcome in a large prospective study where information on the outcome of pregnancy was known in >98.3% of participants and ultrasound was used to determine gestational age (GA).

Methods: As part of the Safe Passage Study of the PASS Network in Cape Town, South Africa, the outcomes of 6 866 singleton pregnancies were prospectively followed from recruitment in early pregnancy until the infant was 12 months old to assess pregnancy outcome. Fetal growth was assessed by z-scores of the birth weight, and GA at birth was derived from early ultrasound assessments. The effects of fetal growth restriction and preterm delivery on pregnancy outcome were determined.

Results: There were 66 miscarriages, 107 stillbirths at ≥22 weeks' gestation, 66 stillbirths at ≥28 weeks' gestation, 29 and 18 neonatal deaths at ≥22 and ≥28 weeks' gestation, respectively, and 54 post-neonatal deaths (28 days - 12 months). The miscarriage rate was 9.6/1 000 and the infant mortality rate 12.4/1 000. Of the births, 13.8% were preterm. For deliveries at ≥22 and ≥28 weeks, the stillbirth rates were 15.7 and 9.8/1 000 deliveries, respectively. For deliveries at ≥22 and ≥28 weeks, the neonatal death rates were 4.3 and 2.7/1 000 live births, respectively. For these pregnancies the perinatal mortality rates were 20.0/1 000 (≥22 weeks) and 12.5/1 000 (≥28 weeks), respectively. Only 15.9% of stillbirths occurred during labour (in 15.9% of cases it was uncertain whether death had occurred during labour). In the majority of cases (68.2%) fetal death occurred before labour, and 82.2% of stillbirths and 62.1% of neonatal deaths occurred in deliveries before 37 weeks. Including the miscarriages, stillbirths and infant deaths, there were 256 pregnancy losses; 77.3% were associated with deliveries before 37 weeks. Only 1.8% of all the women were HIV-positive, whereas the HIV-positive rate was 3.7% among those who had stillbirths. Birth weight was below the 10th centile in 25.6% of neonatal and post-neonatal deaths compared with 17.7% of survivors.

Conclusions: Preterm birth and fetal growth restriction play significant roles in fetal, neonatal and infant losses.