Fetal loss rates after mid-trimester amniocentesis

Abstract

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-trimes- ter genetic amniocentesis performed at our pe- rinatalogy clinic. Study Design: A retrospective review of all the amniocentesis procedures per- formed 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 preg- nancy loss at < 24 weeks of gestation. Setting: Zonguldak Karaelmas University, Faculty of Me- dicine, 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.