Clinical and cytogenetic results of a large series of amniocentesis cases from T urkey: Report of 6124 cases

Aim The aim of this study was to document the clinical and cytogenetic results of a large series of amniocentesis ( AS ) cases from T urkey. Material and Methods Second‐trimester amniocentesis cases performed in S uleymaniye M aternity H ospital for R esearch and T raining between J anuary 2007 and D ecember 2011 were included. Results During this period, 6124 AS were performed. Indications were increased risk in maternal serum screening ( MSS ) (56%), advanced maternal age (29%) and pathologic ultrasound finding (11.5%). Most frequent MSS abnormality was abnormal triple test result (58%). Overall culture success rate was 98.8%. Chromosomal abnormality was detected in 215 (3.6%) of the 6052 cytogenetic results (74.9% numerical, 25.1% structural). Most frequent numerical chromosomal abnormality was trisomy 21 (61.9%). Clinically insignificant polymorphisms were the most frequent structural changes ( n  = 571). Most frequent polymorphism was increase in heterochromatin region in the 1st chromosome ( n  = 158). Advanced maternal age had a positive predictive value of 5.2%. Among the MSS tests, the combined test had the highest positive predictive value (5.2%). Conclusions In our study, abnormal MSS (and among these, abnormal triple test result) was the most frequent indication for amniocentesis. Our overall culture success rate was 98.8%. Frequency of major chromosomal abnormality was 3.2% and trisomy 21 was the most frequent abnormality.