AMNIOCENTESIS carried out in the first three months of pregnancy may not be as safe as chorionic villus sampling (CVS), researchers from King's College Hospital, London, have found. Amniocentesis, which involves taking fluid from the amniotic sac, is traditionally carried out at about 16 weeks but many hospitals are now performing it earlier in pregnancy. According to a study published in the Lancet, however, early amniocentesis carries a significantly higher risk to the foetus than CVS, which involves removing cells from the placenta. Early amniocentesis may also be linked to a higher incidence of foot defects among new- born babies.