A collaborative, retrospective study of patients who had undergone multifetal pregnancy reduction (MFPR) to twins and subsequent genetic amniocentesis was performed to determine if amniocentesis increased the risk of pregnancy loss. Seventy-nine patients from three centres underwent MFPR and subsequent amniocentesis. The pregnancy loss rate was 5.06 per cent in this group. In comparison, the loss rate from a control collaborative series of patients who underwent MFPR only was 11.19 per cent, which was not statistically different. Thus, it appears that amniocentesis following MFPR is unlikely to increase the pregnancy loss rate.