Two years of mid-trimester amniocentesis in Johannesburg.

During a 2-year period 438 mid-trimester amniocenteses were performed on women at risk of producing an abnormal infant. The commonest indications were advanced maternal age (61% of cases), neural tube defects (18%) and Down syndrome (11%). A 92,5% follow-up revealed a spontaneous abortion rate of 3% (1,5% if abortions within 8 days of the procedure were considered). Premature birth occurred in 4,4% of cases, neonatal death or stillbirth in 0,7%, and birth defects which were detectable by amniocentesis in 2%. Abnormalities were detected in 4,9% of cases, so that 95,1% of the patients were reasured by the results obtained. No defects diagnosable by amniocentesis were missed.