Placental sample collection and processing
Births
RECRUITMENT, UTERUS
Births occurred in the communities and at health facilities. Fieldworkers lived within the communities in the study area and operated 24-h surveillance to identify home deliveries and also collect placental tissues. Pregnant women were encouraged to deliver in the health facilities, but were advised to send for the community-based fieldworker when they were in labour if they decided to deliver at home with a trained or untrained birth attendant’s assistance. In the health facilities, fieldworkers also ran 24-h surveillance to identify and collect placental tissues from participants who delivered at these facilities. Participants were identified by the fieldworkers at the maternity wards by direct questioning and by observing the participants maternity card which had been labelled at the time of recruitment or during the pregnancy follow up visits.Whole placenta was collected together with the umbilical cord when it was expelled from the uterus by the attending nurse or birth attendant during the third phase of labour. It was placed flat in a basin with the maternal surface (irregular surface opposite the umbilical cord insertion) up. A full thickness placental biopsy (2.5 × 2.5 × 2.5 Cm