Preterm birth in rural Malawi: high incidence in ultrasound-dated population

BACKGROUND: Preterm birth is the major cause of neonatal death, and has an incidence in industrialized countries of 7%. We have found a high incidence (25-30%) previously in a population of anaemic, pregnant women in southern Malawi, studied with ultrasound dating. METHODS: Cohort study of 512 unselected pregnant women in rural communities in Malawi. All had ultrasound fetal measurements before 24 weeks. RESULTS: 20.3% of women delivered before 37 completed weeks of pregnancy. Babies born before 37 completed weeks but after 32 weeks (16%) were twice as likely to die as babies born at term (6.9 versus 3.4%) but this difference did not achieve statistical significance. For those born between 24 and 33 weeks gestation (4.4%) there was a highly significant increase in perinatal mortality (75%) (p < 0 .000001). CONCLUSIONS: This population has a very high rate of preterm birth, which is probably infection-related. It may be representative of many rural populations in sub-Saharan Africa. Tackling the problem of neonatal mortality in low income countries will require effective methods to prevent preterm birth.