Prenatal testing
Several types of tests are performed throughout pregnancy to monitor the health of you and your baby. Several of these are blood tests which can tell us information about how the baby is developing. Rarely babies can have genetic or other conditions that may cause long term health challenges. The ultrasounds and blood work can help identify these. These tests are not perfect and can have false positives, meaning you have a positive test but the baby does not have the disease. Your doctor will talk to you if any of your tests are concerning or need further evaluation.
Testing during pregnancy
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10-12 weeks: Prenatal blood work including your blood type.
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Non-invasive prenatal genetic testing, this testing is also called cell-free DNA (cfDNA) screening.
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12-16 weeks: Early anatomy ultrasound and nuchal translucency measurements
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16-20 weeks: Maternal serum alpha-fetoprotein (MSAFP) screening blood draw
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18-20 weeks: Detailed anatomy ultrasound
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25-29 weeks: Glucose tolerance test for gestational diabetes, blood test for anemia
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35-36 weeks: Vaginal swab for Beta Strep bacteria (GBS)
Ultrasounds in
pregnancy
Modern ultrasound technology can provide excellent details about the health of your baby and placenta. The second trimester ultrasound, also called the detailed anatomy scan, will look at the organs and body parts of your developing baby including the brain, heart, lungs, stomach, genitals, and extremities. While ultrasounds can identify many problems in a growing baby, not every condition or medical problem will be seen on ultrasound. Additionally, some findings on an ultrasound may cause us worry but will not lead to any challenges or problems after the baby is born. Talk to your doctor if you have questions or concerns about your baby’s ultrasound results.
Did you know?
How does ultrasound work?
An ultrasound uses high frequency sound waves that travel through the belly to create a picture.
Genetic Screening Options
Below is a summary of the California Prenatal Screening Program and Carrier Screening options with links to additional information.
California Prenatal Screening Program
Individuals who choose to participate in the California Prenatal Screening Program provide two blood samples through their prenatal care provider for two types of screening. Both screenings are recommended since they test for different birth defects.
Screening tests
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First trimester: cell-free DNA (cfDNA) screening (recommended from 10 weeks through first day of 21 weeks of pregnancy). This test is also referred to as Noninvasive prenatal testing (NIPT) and is a blood test performed during pregnancy that identifies whether your baby has a higher chance of having certain chromosomal conditions.
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This testing will be completed through the Natera company
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Screening for:
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Trisomy 21 (Down Syndrome)
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Trisomy 18 (Edwards syndrome)
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Trisomy 13 (Patau syndrome)
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*Gender can be included at no additional cost
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Second trimester: Maternal serum alpha-fetoprotein (MSAFP) screening (from 15 weeks through first day of 21 weeks of pregnancy)
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Screening for: Neural tube defects, like spina bifida and anencephaly.
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Additional resources for reading from which the above information was obtained:
Carrier Screening
Carrier screening is a blood or saliva test performed before or during pregnancy that determines the chances of passing on an inherited genetic condition to your child. American College of Obstetrics and Gynecology (ACOG) recommends screening for Cystic Fibrosis and Spinal Muscular Atrophy carrier status in all patients who are pregnant or plan to become pregnant. Additional screening is recommended for at-risk patient populations; however, all patients have the option of completing expanded carrier screening. If you have already completed carrier screening for the recommended conditions, then this does not need to be repeated.
Gestational Diabetes Testing (Glucose Tolerance Test)
The glucose tolerance test helps diagnose if a pregnant woman has gestational diabetes - high blood sugar (glucose) that starts during pregnancy. This test involves drinking a liquid with glucose then checking the pregnant person’s blood sugar at specific intervals. If the blood glucose levels are too high, it is likely to be gestational diabetes.
High blood glucose can lead to significant problems for both the mother and the developing baby. The risks to mom can include increased blood pressure and preterm delivery. The developing baby can develop heart, lung, or skeletal troubles as well as grow too much or not enough during pregnancy.
If your glucose tolerance test is positive, your doctor will discuss your options to help keep your blood glucose levels normal, including diet and nutrition. Proper treatment can improve your health and pregnancy outcome.
​Group B Strep Testing in Pregnancy
Group B Strep (GBS) is one of many bacteria that live on our bodies. About 20% of pregnant women have this bacteria in their body. At the time of birth, the baby can be exposed to the GBS bacteria which can result in pneumonia or a blood infection. Pregnant moms are tested for this bacteria about 3-5 weeks before your due date. If a mom tests positive for the bacteria, it recommended that she receive antibiotics during labor to prevent the baby from getting an infection.
You can learn more from the Centers for Disease Control.
