The proportion of multiple births has increased markedly since 1980 in England and Wales. A major contribution to this trend is thought to be the widespread introduction of assisted reproductive technologies. Despite a continuing (but slower) upward trend in twin maternities, analysis of recent data shows that the rate of triplet and higher order births in England and Wales has declined by one-quarter since 1998. This probably reflects both voluntary and statutory regulation of treatment regimes. This downward trend will help alleviate the high burden of perinatal morbidity and mortality associated with multiple births.