You can’t test twins for Down’s syndrome or spina bifida using a blood test or chorionic villus sampling as the test will not show you which twin is affected. Your choices are to have the nuchal translucency test (a screening test) or amniocentesis (a diagnostic test).

Amniocentesis for twins is a highly skilled procedure because the doctor has to take one sample from each of the bags of water in which your babies are lying. Very occasionally, both babies are inside the same bag of water and then amniocentesis isn’t possible.

If you find out that one baby has Down’s and the other doesn’t, you will have a very difficult decision to make about termination. It is possible to terminate one baby, but there is a risk of losing both babies if the pregnancy miscarries following the procedure. If you find yourself having to make this decision, you should be given time to think and the opportunity to discuss the procedure with your consultant.

You might also want to contact the Twins and Multiple Births Association which will be able to put you in touch with someone who’s had the same experience as yourself. Talking things through with another person who really understands what you’re going through is invaluable.