Who Should be Offered First Trimester Prenatal Screening?
• Chorionic villus sampling (CVS) is a very accurate antenatal test that detects chromosomal abnormalities such as Down’s syndrome. Its main advantage over amniocentesis is that it can be performed earlier — between the 10th and 12th weeks of pregnancy. If you choose to have CVS, a physician will examine your fetus by ultrasound. A small instrument is gently moved across your abdomen to produce images of the fetus on a US screen. The ultrasound exam confirms the dating of your pregnancy, and determines the best area for sampling. Only some women say CVS does not hurt at all, others feel some pressure, gripes or cramping. Many women over the age of 35 choose CVS because the risk of having a child with a serious abnormality increases significantly as you get older. • Women who will be 35 or older at delivery or planning to become pregnant • Couples who have had a baby with a birth defect • Couples who have a relative with a chromosome abnormality (e.g. Down syndrome), mental retardation
