A report of early (13 + 0 to 14 + 6 weeks) and mid-trimester amniocenteses: 10 years' experience.

Objective: To report in singleton pregnancies the post-procedure safety and maternal complications of early amniocenteses performed between 13 + 0 and 14 + 6 weeks of gestation and mid-trimester amniocenteses performed between 15 + 0 and 18 + 6 weeks of gestation.

Methods: The study was carried out at the Prenatal Diagnosis Center, Siena University, Italy, during a 10-year period, following the Regional Protocol for Prenatal Diagnosis. Our study population included 3769 amniocenteses, 475 early and 3294 mid-trimester. Complications considered included miscarriage (immediately after the procedure and until 24 weeks of gestation), blood-stained amniotic fluid, failed cell culture, amniotic fluid leakage, preterm premature rupture of the membranes (PROM), preterm delivery and presence of neonatal talipes equinovarous.

Results: Cytogenetic anomalies were found in 111 cases (2.9%), 18 occurring early and the other 93 in mid-trimester. Miscarriage occurred in two cases in the early amniocentesis group (0.4%) and in ten cases among the mid-trimester group (0.3%). The overall loss of pregnancies due to amniocentesis in this study was 0.3%. Amniotic fluid was stained in 1.2% in the early group and 0.9% in the mid-trimester group. Amniotic fluid leakage was noted in 1.4% and 1.2%, preterm PROM was noted in 3.3%) and 3%, and preterm delivery occurred in 8% and 7.6%, respectively. There were no cases of failed amniotic culture and no cases of talipes equinovarous documented.

Conclusions: The risks of early amniocentesis performed between 13 + 0 and 14 + 6 weeks appear to be comparable to those of mid-trimester amniocentesis and thus early amniocentesis could be offered to the parents, as an alternative to chorionic villus sampling, in order to obtain cytogenetic results earlier in pregnancy without a significantly increased risk for both mother and fetus. Further operators' experience with the method, based on long and accurate follow-up, and further studies are necessary to assess the safety of the method.