Total pregnancy loss after chorionic villus sampling and amniocentesis: A cohort study

Objectives To identify maternal-, operator-and procedure-related variables that affect procedure-related pregnancy loss after transcervical (TC) and transabdominal (TA) chorionic villus sampling (CVS) and amniocentesis and to estimate the rates of spontaneous and procedure-related loss in comparable subgroups of women.

Methods This was a retrospective cohort study conducted at the University Medical Center Groningen and the Academic Medical Center, The Netherlands. Databases of both centers were searched to identify singleton pregnancies that had undergone a combined test and/or anomaly scan at around 20 weeks' gestation, or an invasive procedure (CVS and/or amniocentesis) between January 2001 and December 2011. Maternal characteristics, obstetric history, technical aspects of the invasive procedure, ultrasound examinations and fetal and neonatal outcomes were available for 29 201 cases. Women were categorized, according to the type of examination they had received, into the following five groups: first-trimester combined test (and 20-week anomaly scan); 20-week anomaly scan only; CVS; amniocentesis; amniocentesis after unsuccessful CVS. Rates of fetal loss were compared between groups.

Results Variables significantly associated with a higher rate of fetal loss were, for CVS, repeat attempts during the procedure, use of TC cannula instead of biopsy forceps, gestational age at procedure >= 13 weeks and a pregnancy after assisted reproductive techniques, and, for amniocentesis, if indication was fetal anomaly or family history of anomalies and repeat attempts during the procedure. In women aged >= 36 years who did not undergo an invasive procedure, spontaneous fetal loss rate (FLR) after first-trimester combined test was 1.40%, whereas after CVS, FLR was 2.76% and 2.43% for a TC and TA approach, respectively. The additional risk of fetal loss with TC-CVS was therefore 1.36% (1 : 74), which varied according to the instrument used (0.27% for forceps and 3.12% for cannula), and with TA-CVS was 1.03% (1 : 97). In women aged >= 36 years who underwent a 20-week anomaly scan only, spontaneous FLR was 0.63%. In women who underwent amniocentesis solely because of advanced maternal age, FLR was 1.11%. The additional risk of fetal loss with amniocentesis was 0.48% (1 : 208).

Conclusion The total rate of procedure-related fetal loss after TA-and TC-CVS and amniocentesis appears lower than the risks on which women are currently counseled. There was a trend for a decrease in risk when the level of experience of the operator increased. Copyright (C) 2016 ISUOG. Published by John Wiley & Sons Ltd.