then the value of a diagnostic test like amniocentesis or chorionic villi sampling (CVS) isn't there," Dr. Mennuti says. The test might be worthwhile, however, if a couple would consider ...

These are an amniocentesis test, at 16 weeks, in which a needle is put through the stomach and fluid from around the baby is taken, or a chorionic villus sample, at 11 to 15 weeks, in which cells ...