PROSPECTIVE PILOT EVALUATION OF EARLY (11-14 WEEKS GESTATION) AMNIOCENTESIS IN 75 PATIENTS

Prenatal diagnosis by amniocentesis has traditionally been accomplished at 15-18 weeks' gestation. Cytogenetic and biochemical results are usually available in 7-28 days, that is, by 16-22 weeks' gestation. Amniocentesis performed at 11-14 weeks facilitates earlier diagnosis, in some cases before 12 weeks' gestation. During the study period, 726 genetic amniocenteses were performed, 75 as part of the prospective early amniocentesis protocol. Of the 75 patients included in this pilot study, as well as the 75 patients in the control group, the success rate for obtaining an accurate cytogenetic diagnosis by early amniocentesis was 75/75 (100%) and the complication rate was 2/75 (2.6%: incidence of need for repeat amniocentesis, 1/75; uncorrected spontaneous abortion rate, 1/75). The indications for referral, population profile, mean gestational age at testing, and both the cytogenetic as well as obstetric outcomes are summarized in the report. This pilot study supports the hypothesis that amniocentesis at 11-14 weeks is efficacious when performed by experienced personnel and affords earlier counseling, testing, and availability of results compared to traditional amniocentesis.