Risk of amniocentesis and laboratory findings in a series of 1500 prenatal diagnoses.

The experiences with 1500 midtrimester prenatal diagnoses are reported. Abnormal findings of amniotic fluid investigations led to 43 therapeutic abortions. In +/- 30 per cent of the chromosome anomalies diagnosed, the significance of the effect on fetal development was inconclusive. The outcomes of all pregnancies except one are known. Fetal loss and perinatal mortality involved 69 cases, 23 (33 per cent) of which occurred within three weeks after amniocentesis. In these 23 cases there appeared to be a relationship between the degree of experience of the gynaecologist and fetal loss: 3.7 per cent when this experience was limited to a maximum of 10 punctures diminishing to 0.3 per cent with an experience of more than 50 punctures. It is concluded that the risk of an abortion due to amniocentesis decreases as the gynaecologist becomes more experienced with the puncture technique.