During your pregnancy, we provide prenatal screenings to help determine your risk of having a baby with certain chromosomal abnormalities.
Genes are structures inside our body’s cells that contain biological information. Genes make up larger structures called chromosomes, which are inside each cell’s deoxyribonucleic acid (DNA). Changes to or duplicate copies of chromosomes can occur as the cells are developing. This can result in conditions such as:
Prenatal Sonograms and Diagnostic Tests
First-trimester screenings for Down syndrome are available to any pregnant woman, regardless of family history. Other screenings are only recommended for women at higher risk for having a baby with certain congenital conditions.
An ultrasound, or sonogram, uses painless, high-frequency sound waves to allow doctors to examine organs and tissues. Similar to sonar or radar, the waves reflect back to create an image of the organ or other structure being examined. Unlike an X-ray, an ultrasound does not involve any exposure to radiation. We may use ultrasound to:
- Assess risk of certain medical conditions
- Check placement of the placenta
- Confirm multiple fetuses
- Determine gestational age of the fetus
- Evaluate pregnancy progress
- Guide needle placement for amniocentesis or chorionic villus sampling
When do you get a fetal sonogram?
A sonogram during the first 12 weeks of pregnancy can help confirm and date the pregnancy. An ultrasound when you are between 18 and 22 weeks pregnant gives a more detailed picture of the baby’s anatomy. Ultrasounds may be repeated if the baby’s health needs to be monitored more closely.
What to expect
Ultrasound is a painless test. The technologist will spread a clear, water-based gel over the abdomen or inside the vagina and then slide a wand, called a transducer, over the gel. The physician will discuss the results and recommendations with you at the conclusion of the ultrasound.
Screenings and Diagnostic Tests
We use blood tests, ultrasound and other techniques to detect and diagnose chromosomal abnormalities. We use the least invasive techniques possible in order to reduce potential risk of complications or miscarriage.
- First trimester screening involves laboratory tests and ultrasound to indicate the risk of having a baby with Down syndrome or other chromosomal conditions. We perform this test between 12 and 13 weeks plus 5 days into your pregnancy.
- Non-invasive prenatal testing (NIPT), also known as cell-free fetal DNA screening, is a screening test for women at high risk of having a baby with a chromosomal condition. For this test, we draw some of the mother’s blood, which contains DNA from both the mother and the baby. We perform this test after 10 weeks.
- Amniocentesis is a diagnostic tool we use if a screening test indicates a chromosomal condition. Guided by an ultrasound image, we insert a long, thin needle into the abdomen and remove a small amount of the amniotic fluid inside the uterus, which we send to an accredited laboratory for analysis. We usually perform this test between 15 and 22 weeks. We can perform it as early as 12 weeks, but the risk of complications rises.