Prenatal Testing Timeline – What You Need to Know Throughout Your Pregnancy


Throughout your pregnancy, your obstetrician will closely monitor the health of you and your baby. Part of this process will involve ultrasound screenings and blood tests. Your doctor may also recommend prenatal screening to analyze the risk that your baby may have a genetic disorder or birth defect. Each test is performed according to the gestation time of your baby in order to ensure that your doctor will be able to provide you with the most accurate information for a healthy pregnancy.

First Trimester

As early as week 10

Noninvasive prenatal testing or NIPT testing – Noninvasive prenatal testing allows doctors to analyze the fetal DNA from the placenta using a blood draw from the mother. The information provided by this test allows doctors to assess the risk that your baby may have a chromosomal abnormality such as Trisomy 21 (Down syndrome), Trisomy 18 (Edwards syndrome), Trisomy 13 (Patau syndrome), and much more.

Between weeks 10 and 12

Chorionic villus sampling (CVS) – CVS is a diagnostic test that is used if a screening test shows a high risk that your baby may have a genetic disorder. During this test, your doctor will collect a sample of placental tissue from the cervix using a catheter.

Between weeks 11 and 14

Ultrasound and maternal blood test – During the first trimester, your doctor will want to monitor for fluid in the back of the baby’s neck, called nuchal translucency (NT). When fluid is present behind the neck, this may indicate an increased risk of chromosomal abnormalities or a heart defect. Additionally, your doctor will want to perform testing on the mother’s blood to measure levels of two substances: Pregnancy-associated plasma protein screening (PAPP-A) and Human chorionic gonadotropin (hCG). Elevated levels of either one of these substances indicate an increased risk of a chromosome abnormality.

Second Trimester

Weeks 15-20

Triple/quad screen – The triple/quad screen test analyzes the mother’s blood for three (triple screen) or four (quad screen) substances: alpha-fetoprotein (AFP), human chorionic gonadotropin hormone (hCG), estriol, and inhibin A. The levels of each substance will indicate either a low risk or a high risk of a chromosomal abnormality.

Amniocentesis – Amniocentesis is recommended by doctors when a screening test reveals a high risk that your baby may have a genetic disorder. This test is performed by collecting a sample of amniotic fluid with a needle through the abdomen. Cells that are shed by the fetus are analyzed to determine if a specific genetic condition is present, such as a chromosomal disorder or a neural tube defect.

Third Trimester

Typically, during the third trimester, your doctor will monitor the health of your baby using a fetoscope to hear the heartbeat in addition to an ultrasound device to count the heart rate. During your pregnancy, your obstetrician will use continuous electronic fetal monitoring to closely monitor the baby’s heart rate.

Talk to Your Doctor About Testing Options

Talk to your doctor about standard tests that are performed during pregnancy as well as optional screening tests. Your obstetrician will explain the timeline associated with each test, as well as which ones are standard and which ones are recommended.

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