The quad screen is done in the second trimester, usually between 15 and 20 weeks of pregnancy. Ideally, the test should be performed in conjunction with first-trimester screening tests. This combination is known as integrated or sequential screening. These screening tests help you assess your baby’s chances of having certain genetic diseases and birth defects. The results can help you decide whether to have amniocentesis, an invasive diagnostic test, to find out for sure about your baby’s condition.
The conditions it screens for are Down syndrome and trisomy 18, which are chromosomal abnormalities, as well as neural tube defects, such as spina bifida. The quad screen is done in the second trimester, usually between 15 and 20 weeks of pregnancy.
As with any screening test, an abnormal result does not mean that the fetus definitely has a birth defect or genetic condition. It only means that the blood levels of these four substances suggest that a woman’s risk is increased of having a baby with certain conditions. Women who have a result suggesting increased risk are typically offered further testing.
