Induced abortions should be included

EDITOR—Dolovich et al have reported their meta-analysis concerning use of benzodiazepines during the first trimester of pregnancy and the risk of oral clefts or major congenital malformations.1 In the cohort studies no increased risk of congenital malformations was found, while case-control studies showed an increased risk of both oral clefts and major congenital malformations. The authors excluded studies from the meta-analysis if only stillbirths or abortions were included.

The paper missed important information about the criteria for inclusion in the meta-analysis. During the past 10-15 years prenatal diagnosis of congenital malformations has increased significantly in many countries and is often followed by termination of pregnancy if severe malformations are diagnosed.2 The Eurocat project is a European epidemiological programme surveying congenital malformations. The Eurocat registries are population based and based on multiple sources of information; they include information about live births, deaths of fetuses with gestational age ≥20 weeks, and induced abortions after prenatal diagnosis of malformations.

During 1990-4 there were 13 registries following strict Eurocat methodology and where induced abortion after prenatal diagnosis of congenital malformations was noted. The 13 registries covered 1 284 599 births. For this period the contribution of induced abortion in the registries …