Is CVS safer than amniocentesis?

Neither is clearly safer. RCOG guidance gives a single figure covering both: the additional risk of miscarriage following amniocentesis or CVS, performed by an appropriately trained operator, is likely to be below 0.5%. Systematic review data show them closely comparable — one pooled analysis put procedure-related loss at 0.11% for amniocentesis and 0.22% for CVS; an updated analysis found 0.35% for both. ISUOG notes observational CVS loss rates ranging from 0.2 to 2%, reflecting how much these figures vary between studies and centres. For twins, the additional risk is around 1% for either procedure. What genuinely differs: Timing. CVS from 10+0 weeks, preferably 11+0 onwards. Amniocentesis from 15+0 weeks. An earlier answer is CVS's main advantage. What is sampled. CVS takes placental tissue; amniocentesis takes fluid containing your baby's cells. Because CVS samples the placenta, it shares NIPT's vulnerability to confined placental mosaicism — mosaicism is reported in about 1% of chorionic villus specimens compared with 0.25% of amniocentesis specimens, and an unclear CVS result sometimes requires a follow-up amniocentesis. Twin-specific: CVS carries an additional roughly 1% risk of cross-contamination, where both fetuses are inadvertently sampled, giving misleading results. What matters more than the choice between them: operator experience. ISUOG documents lower loss rates where more than 100 procedures are performed annually. Ask your unit their volume and their own audited rate. If you are Rh negative, you will need anti-D after either.