Midtrimester genetic amniocentesis in eastern Ontario: a review from 1970 to 1985.

Greater use of genetic amniocentesis in the Eastern Ontario region occurred once the results from the various national trials were published. Acceptance also paralleled an increase in the number of low parity older women having children and the centralisation and greater publicity given to our programme in the late 1970s. A centralised approach has had the positive effects of preventing unnecessary procedures, assuring appropriate patient counselling, follow up, and review, and of increasing obstetric and laboratory expertise. Advanced maternal age has been largely responsible for the increased demand for the service and accounted for an increasing proportion of tests performed, while the absolute number for several other diagnostic categories remained unchanged. We found no evidence that women with a history of previous miscarriage had a higher rate of pregnancy loss following the procedure, and comparison with a group of women who declined amniocentesis did not show that the test increased the risk of miscarriage.