Amniocentesis before 15 weeks' gestation: technical aspects and obstetric risks

In a prospective case-control study, early amniocenteses (EAC, n = 242) at between 12 and 14 weeks gestation, were compared with standard amniocenteses (SAC, n = 242) performed at between 15 and 24 weeks gestation. The medical records of these 484 cases were reviewed for indications, success rate, color and volume of amniotic fluid, gestational age, number of needle insertions, location of the placenta, culture failure rate, obstetric complications and therapeutic abortion rate. There were no significant differences between the two groups in success rate, in culture success rate or in the outcome of the pregnancies. The volume of the sample taken was smaller in the EAC patients (P < 0.001), and therapeutic abortions were performed significantly earlier (P < 0.02.) Results show that EAC is feasible from 11 weeks' gestation, and can be performed for the usual indications as an alternative to chorionic villus sampling. In the near future, cytogenetic techniques will enable results to be obtained in less than a week.