The WHO antenatal care randomised controlled trial: rationale and study design

Abstract

The World Health Organisation and collaborating institutions in developing countries are conducting a multicentre randomised controlled trial to evaluate a new antenatal care (ANC) programme, consisting of tests, clinical procedures and follow-up actions scientifically demonstrated to be effective in improving maternal and newborn outcomes. These activities are distributed, for practical reasons, over four visits during the course of pregnancy and are aimed at achieving predetermined goals. The study is taking place in four countries, Argentina, Cuba, Saudi Arabia and Thailand. Recruitment of study subjects started on 1 May 1996. All 53 ANC clinical units had been enrolled by December 1996. Clinics in each country were randomly allocated (cluster randomisation) to provide either the new programme or the traditional programme currently in use. Approximately 24,000 women presenting for ANC at these clinics over an average period of 18 months will have been recruited. As women attending the control clinics receive the 'best standard treatment' as currently offered in these clinics, individual informed consent is requested only from women attending the intervention clinics. Authorities of the corresponding health districts and all participating clinics have provided written institutional informed consent before randomisation. The primary outcome of the trial in relation to maternal conditions is the rate of a morbidity indicator index, defined as the presence of at least one of the following conditions for which ANC is relevant: (a) pre-eclampsia or eclampsia during pregnancy or within 24 h of delivery; (b) postpartum anaemia (haemoglobin < 90 g/L); or (c) severe urinary tract infection/pyelonephritis, defined as an episode requiring antibiotic treatment and/or hospitalisation. The primary fetal outcome is the rate of low birthweight (< 2500 g). Adverse maternal and fetal outcomes are expected for approximately 10% of the control group. Several maternal and perinatal secondary outcomes are also considered. A comprehensive cost-effectiveness analysis and women's and providers' satisfaction evaluation are performed concurrently with the trial. Health-care programmes should be rigorously evaluated by randomised controlled trials, which are feasible in developing countries and should be conducted before introducing new treatments or health interventions.

PIP: The procedures and examinations included in currently practiced prenatal care have not been subjected to systematic, scientifically rigorous evaluation. The World Health Organization (WHO) Antenatal Care Randomized Controlled Trial is evaluating a new prenatal care regimen with demonstrated efficacy in improving maternal and newborn outcomes. Program activities include screening for health conditions that increase the risk of specific adverse pregnancy outcomes, therapeutic interventions known to affect these outcomes beneficially, and education of pregnant women regarding potential health emergencies and appropriate responses. The study's hypothesis is that the tests, clinical procedures, and follow-up actions associated with this approach, delivered over the course of four visits during pregnancy, are more effective than the traditional prenatal care package in terms of specific maternal and perinatal results without being more expensive. This paper addresses the rationale, design, and methodology of this trial. 53 prenatal care clinics in four well-defined geographic areas (Khon Kaen Province, Thailand; Havana, Cuba; Rosario, Argentina; and Jeddah, Saudi Arabia) have been randomized to the two arms of the study. By the end of 1997, 24,000 women presenting for prenatal care at these sites had been enrolled. The primary maternal outcome is the morbidity indicator index, defined as the presence of at least one of the following conditions: pre-eclampsia or eclampsia during pregnancy or within 24 hours of delivery, postpartum anemia, or severe urinary tract infection/pyelonephritis. The primary fetal outcome is the rate of low birth weight. A comprehensive cost-effectiveness analysis and provider satisfaction evaluation will be performed concurrently with the trial. Data collection will be completed in 1998.