A pregnancy register of patients receiving carbamazepine in the UK

Abstract

AbstractFrom 1978 to 1990, CIBA‐GEIGY Pharmaceuticals (UK) were notified of the pregnancy outcome of 154 women who were being treated with Tegretol® (carbamazepine) during their pregnancy. The first contact of these reports occurred either before the end of the pregnancy (prospective reports) or after the result of the pregnancy was known (retrospective reports). Prospective reports were followed up in order to ascertain details of each pregnancy and the health status at birth of the offspring. The same information for the retrospective reports was collected after the pregnancy outcome occurred. Three possible outcomes of pregnancy were identified: (1) Patients whose pregnancies resulted in normal healthy babies, (2) patients whose pregnancies ended in premature spontaneous abortion and (3) patients whose pregnancies resulted in babies with congenital malformations. A total of 88 patient's reports were prospective. Of these, 75 pregnancies resulted in normal babies, 9 in spontaneous abortions and 4 in abnormal babies (5%). A total of 65 patient's reports were retrospective. Of these, 23 pregnancies resulted in normal babies, 8 in spontaneous abortions and 34 in abnormal babies (60%). This major reporting bias in the retrospective group discourages its use in the quantitative safety assessment of medicines given to pregnant women.