MONITORING DATA AND SAFETY IN THE WHO ANTENATAL CARE TRIAL

A committee to monitor data and safety in a large clinical trial shoul d have members with expertise in biostatistics, epidemiology and the c linical field relevant to the trial. Its mandate should cover both log istics and the safety of study subjects, issues which to some extent o verlap. While a steering committee and field staff members ideally sho uld be blinded to the experimental and control arms of a randomised cl inical trial, the data and safety monitoring committee (DSMC) should h ave full access to interim trial data to fulfil its role as watchdog. One initial question to be resolved concerns if and when to advise sto pping a trial because of danger to study subjects, or on the other han d obvious benefits, in one trial arm. The DSMC of the WI IO Antenatal Care Trial decided not to establish any definite stopping rules before implementation. After a scrutiny of the adopted procedures for data c ollection and handling, the DSMC received monthly reports oi: recruitm ent, and individual summary reports of three adverse events by site an d trial arm: maternal deaths, fetal deaths and cases of eclampsia. At the time of writing (December 1997) recruitment to the trial is almost complete, but data collection will continue throughout most of 1998, until every index pregnancy has ended in birth or miscarriage. So far, the balance of untoward events between the intervention and control a rms have not given cause for alarm.