Fetal loss rate after second trimester amniocentesis at different gestational age

Background. Recent studies have debated the safety of early amniocentesis, one of which reported a significant increase in spontaneous fetal losses fo llowing amniocentesis performed at 10-13 weeks of gestation. The aim of thi s study was to determine the fetal loss rate following amniocentesis perfor med at different stages in the second trimester. Methods. One thousand six hundred and fifty-one consecutive amniocenteses u ndertaken in a low risk population between 13 weeks+0 days and 20 weeks+6 d ays were evaluated. In 87% of the women the reason far testing was maternal age (mean 37.1 years). Data concerning patients, procedure details and pre gnancy outcome were recorded. Results. Spontaneous abortion before 28 weeks of gestation occurred in 1.1% , one third of which were within two weeks and the remaining within seven w eeks after the procedure. The fetal loss rate was higher when the amniocent esis was performed earlier in pregnancy, at 13 weeks+0 days exceeding 3%. A bnormal color of the amniotic fluid and leakage of amniotic fluid were stro ng predictors of fetal loss. Transplacental needle insertion did not increa se the risk of pregnancy loss. Conclusion. Amniocentesis performed very early in the second trimester is f ollowed by an increased fetal loss rate that cannot be explained solely by a higher risk of spontaneous abortion at this time of gestation.