Birth worries.

PREGNANT women undergoing tests for foetal abnormalities could be up to twice as likely to miscarry if they attend a small hospital unit, according to new research. Some 30,000 women a year in the UK undergo amniocentesis or chorionic villus sampling (CVS) to detect possible problems with a pregnancy. Amniocentesis indicates the likelihood of the baby developing chromosomal conditions, such as Down's syndrome or Edward's syndrome. The test carries a risk of miscarriage and is usually only offered to women when there is a significant risk the baby will develop such a condition. CVS tests are usually carried out earlier in pregnancy and detect serious foetal problems. The study, involving more than 64,000 pregnant women, found that miscarriage rates were higher at smaller hospital units.

The lead author, Prof Ann Tabor from the department of foetal medicine, said: The very clear variations in miscarriage rates between units with different levels of expertise demonstrate that the invasive procedures play a role in miscarriage rates."