Prospective study of amniocentesis performed between weeks 9 and 16 of gestation: its feasibility, risks, complications and use in early genetic prenatal diagnosis.

This paper demonstrates that the outcome of amniocenteses performed between the 9th and the 14th weeks is similar to that of amniocenteses performed between the 15th and 20th weeks. We have performed and prospectively followed 615 amniocenteses between the 9th and 16th weeks of gestation. The outcome, risks, and complications are similar to those of amniocenteses at the usual time (after 15 weeks) and to the other groups of early amniocentesis (before 15 weeks). Early amniocentesis differs from amniocentesis at the usual time in that it carries higher rates of fetal losses and of amniotic fluid leakage, more confined cytogenetic abnormalities, and an increased number of patients who have the procedure postponed. Two cultures (0.32%) failed to produce results, 595 (96.7%) samples were obtained at the first tapping, 20 (3.3%) at the second attempt. alpha-Fetoprotein levels reach their maximum at 13 weeks. Amniocenteses between 15 and 16 weeks (293, or 47%) constitute the control group, those between 9 and 14 weeks (322) the experimental group. Early amniocentesis appears to be a safe early genetic prenatal diagnosis technique, an alternative to chorionic villi sampling.