First trimester: Types of screens
Questions about ethnicity
In every ethnic group there are certain problems, disorders or diseases that occur more often than in the general population. Because of your ethnic group, you may be offered carrier testing to see if your baby is at risk for having the problem. A carrier is a person who is healthy but faces the risk of having a baby with a specific disease if the partner is also a carrier. Carrier testing is important because most carriers do not have a family history of the problem.
Questions about family history
At your first prenatal visit you will be asked questions about your family history. A history of certain birth defects, illnesses, genetic disorders, infertility, miscarriage, or other problems may suggest an increased risk to your baby. Genetic counseling can help determine if there is an increased risk and what, if any, tests are available to diagnose or rule out the problem.
Most birth defects do not increase with the mother's age. However, there are some chromosomal problems that occur more often in older women. Down syndrome is the most well known. In the past, a woman's age determined whether she was offered chromosomal testing rather than screening. However, the American College of Obstetrics and Gynecology (ACOG) now advises that all pregnant women, regardless of their age, have the option of diagnostic testing.
ACOG also advises that screening be offered to women who are unsure about having diagnostic testing. ACOG recognizes that a woman's decision is based on many factors, such as a family or personal history of birth defects, the risk of a chromosome abnormality or inherited condition, and the risk of pregnancy loss from the testing procedure.
A serum screen is a blood test that looks for specific proteins produced by your baby or the placenta. The amount of these proteins can help determine the chance of a problem.
Sonograms can be used to screen for physical problems and abnormal development.