In pregnancies with a higher risk for genetic disorders (assessed based on multiple factors such as advanced maternal age, ultrasound scan, screening tests etc), the woman may be advised to undergo an invasive procedure such as amniocentesis or chorionic villous sampling (CVS).
Many couples and the referring clinicians are often concerned about the risk of pregnancy loss that is associated with such invasive procedures. This is also the cause of refusal to undertake a diagnostic test. The important question here is – how risky are these invasive procedures?
Traditionally the pregnancy loss rates following amniocentesis and chorionic villous sampling has been quoted as 0.5 – 1% and 1 to 2 % respectively.
However a recent meta-analysis published in the White Journal (International Journal of Ultrasound in Obstetrics and Gynecology) states that the pregnancy loss rates following amniocentesis and chorionic villous sampling in expert hands is 0.11% and 0.22 % respectively. It means that if a patient undergoes the procedure of amniocentesis in expert hands, the chances that she is likely to miscarry is 1 per 1000 which is far less compared to 1 per 100 that was traditionally quoted. This also means that the risk of miscarriage is far lesser than the risk of various genetic disorders. For e.g. the risks of down syndrome for a 35 year old woman can be as high as 1 in 400.
The findings of this study shouldenable the couples, clinicians and counsellors to arrive at a more balanced decision. These findings would indeed be very reassuring to the coupleswho take up the invasive procedures as part of prenatal diagnostic testing.
Reference: Ultrasound ObstetGynecol 2015; 45: 16–26. Procedure-related risk of miscarriage following amniocentesis and chorionic villus sampling: a systematic review and meta-analysis R. AKOLEKAR, J. BETA, G. PICCIARELLI, C. OGILVIE and F. D’ANTONIO
Fetal Medicine Specialist