Coelocentesis was performed in 20 singleton pregnancies at 6-10 weeks of gestation and 2-13 days before planned termination. The control group consisted of 100 women who were also undergoing planned termination and were matched with the study group for maternal age and gestation. During the follow-up period, there were five miscarriages (25 per cent) after coelocentesis and five in the control group (5 per cent) (chi 2 = 6.68; P < 0.01). The high risk of miscarriage following coelocentesis makes the technique unsuitable for early prenatal diagnosis.