The Zambian Preterm Birth Prevention Study (ZAPPS): Cohort characteristics at enrollment

Abstract

Background: Sub-Saharan Africa bears a disproportionate burden of preterm birth and other adverse outcomes. Not only is the background rate of preterm birth higher than in North America and Europe, but many facilities lack essential equipment and personnel resources to care for preterm neonates. A better understanding of the demographic, clinical, and biologic underpinnings of preterm birth is urgently needed to plan interventions and inform new discovery.  Methods: The Zambian Preterm Birth Prevention Study (ZAPPS) is a prospective antenatal cohort established at the Women and Newborn Hospital of the University Teaching Hospital (UTH) in Lusaka, Zambia. We recruit pregnant women from the antenatal clinics of district health centers and the UTH for study participation. Women undergo ultrasound examination to determine eligibility by gestational age criteria. Enrolled participants receive routine antenatal and postnatal care, lab testing, midtrimester cervical length measurement, serial fetal growth monitoring and careful assessment of birth outcomes.  Results: Between August 2015 and September 2017, we screened 1784 women, of whom 1450 (81.2%) met inclusion criteria and were enrolled. The median age at enrollment of study participants is 27 years (IQR 23–32). Participants are enrolled at a median gestational age of 16 weeks (IQR 13–18). Among all parous participants (N=866; 64%), 21% (N=182) reported a prior miscarriage, 49% (N=424) reported a prior preterm birth, and 13% (N=116) reported a prior stillbirth. The HIV seroprevalence in our cohort is 24%. Discussion: We have established a large antenatal cohort to characterize the epidemiological and biological determinants of adverse birth outcomes in Lusaka, Zambia. Findings from this cohort will help guide future studies, clinical care, and policy in the prevention and treatment of adverse birth outcomes.