Optional Fetal Abnormality Tests Available
There are several optional tests available to all pregnant women. While there are no prenatal therapies or cures for fetal abnormalities, parents can use early diagnosis to prepare for the birth of the baby or to plan for termination of the pregnancy. Screening tests are noninvasive and can determine if there is a high or low risk for certain abnormalities. Diagnostic tests are invasive and can determine if a certain abnormality is present or not. Testing is not perfect and is only available for certain abnormalities. Fetal abnormality testing is not required, but is an option which may be chosen by the patient in consultation with her care providers.
NONINVASIVE SCREENING TESTS
• Cystic Fibrosis Carrier Status
Cystic Fibrosis is an inherited genetic disease that is characterized by severe respiratory and digestive problems. The test for cystic fibrosis is a Maternal Blood Test that evaluates whether the mother is a carrier of the disease. If this test is positive, we then screen the father’s blood for the gene mutation. If both are positive, the parents may opt to have an amniocentesis to determine if the baby has cystic fibrosis.
• First Trimester Screening + Second Trimester AFP
This screening pairs an Ultrasound to evaluate specific measurements of the baby with Maternal Blood Tests done at the same time. This determines if the baby is at high or low risk for specific chromosomal abnormalities. This screen can detect 90% of Down Syndrome cases and 97% of Trisomy 13 or 18. This test has a 5% False Positive Rate. If this screening shows that the risk of abnormalities is high, you may opt to have an invasive test to confirm the diagnosis.
Patients may also opt to have blood drawn again in the second trimester to screen for spina bifida. This screen can detect 98% of open neural tube defects. There is a 6% False Positive Rate. If this screening test shows that the risk is high, you may opt to have an invasive test to confirm the diagnosis.
• Second Trimester Screening
This Maternal Blood Test that determines if the baby is at high or low risk for specific chromosomal abnormalities or open neural tube defects/spina bifida. This screen can detect 80% of Down Syndrome cases, 70% of Trisomy 13 or 18, and 98% of spina bifida. There is a 6 % False Positive Rate. If this screening test shows that the risk is high, you may opt to have an invasive test to confirm the diagnosis.
INVASIVE DIAGNOSTIC TESTS
• Chorionic Villus Sampling
This diagnostic test is an ultrasound guided needle aspiration of cells from the placenta, and it can detect 99% of chromosomal defects as well as some other inherited disorders. The risk of complications, including fetal injury and miscarriage, is approximately 1/100.
This diagnostic test is an ultrasound-guided needle aspiration of fluid from around the fetus, and it can detect 99% of chromosomal defects and open neural tube defects as well as some other inherited disorders. The risk of complications-including infection, bleeding, fetal injury, rupture of membranes, and miscarriage-is approximately 1/300.
This is a consultation between a patient and an expert in the field of inheritable diseases. The visit involves evaluation of the patient’s family history and discussion of testing options available. This service is widely available; however, it is commonly utilized in patients who are at high risk for fetal abnormalities.