Fetal loss rates after mid-trimester amniocentesis

Objective: Amniocentesis is an invasive cytogenic test traditionally associated with a 1/200 procedure–related pregnancy loss rate. Recent studies have questioned the validity of the traditionally stated rate. The purpose of this study was to document the results of second-trimester genetic amniocentesis performed at our perinatalogy clinic. Study Design: A retrospective review of all the amniocentesis procedures performed between 15 and 22 weeks of gestation on singleton pregnancies between May 2004 and December 2008 was performed. Spontaneous loss was defined as any unintentional pregnancy loss at < 24 weeks of gestation. Setting: Zonguldak Karaelmas University, Faculty of Medicine, Department of Obstetrics and Gynecology. Population: Pregnant women followed at the Obstetrics Department. Methods: A retrospective review of all the amniocentesis procedures performed between May 2004 and December 2008 was performed. Main outcome measure: Pregnancy loss due to amniocentesis. Results: A total of 447 amniocentesis procedures were performed during the study period. The major indication for amniocentesis was positive maternal triple screening (44%). The mean gestational age at amniocentesis was 18.80 ± 2.70 weeks. The results of cytogenetic analyses revealed an abnormal karyotype in 19 pregnancies (4.3%), nine of which were trisomy 21. The overall spontaneous loss rate was 0.89% (n = 4). Conclusion: It would be useful for each center to investigate its own pregnancy loss rate and thereby provide a firmer basis for its policy for counseling women requesting amniocentesis. If enough such investigations were reported, a true benchmark figure could also emerge.