Short-term outcomes after second-trimester genetic amniocentesis in Siriraj Hospital

To determine the short-term outcomes of second-trimester genetic amniocentesis at Siriraj Hospital, Bangkok, Thailand.

In a retrospective descriptive study, data were assessed from women with a singleton pregnancy who underwent genetic amniocentesis between 16 and 21 gestational weeks at the Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, Siriraj Hospital, from May 2007 to June 2012. The amniocentesis records and medical data of all women were analyzed statistically.

During the 5-year period, complete data were collected for 3307 pregnant women. The rate of total pregnancy loss within 4 weeks of testing was 7 out of 3307 (0.2%; 95% confidence interval, 0.1%-0.4%). Advanced maternal age (≥35 years) was the most common indication for amniocentesis (94.6%). The culture failure rate was 0.2%. Chromosomal abnormalities were detected in 109 pregnancies (3.3%); trisomy 21 was the most prevalent abnormality (0.8%). The possible risk factors of fetal loss were early amniocentesis (gestational age, <18 weeks) (P=0.013), abnormal fetal sonography (P=0.004), culture failure (P=0.015), and old-blood- or murky-stained amniotic fluid (P=0.036).

Second-trimester genetic amniocentesis resulted in 0.2% of total pregnancy loss within 4 weeks of testing. This information is essential for patient counseling before amniocentesis.