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Prenatal Screening Tests continued...

While screening tests are recommended for all women, whether you get them is up to you. Your doctor or midwife may suggest you speak with a genetic counselor before you make any decisions. If you have any questions or concerns, be sure to bring them up before having any tests.

Screening tests include:

Nuchal translucency screening. During your first trimester, your doctor or midwife may do a special type of ultrasound to check the thickness of your baby's neck along with blood tests to look for certain things that may be linked to birth defects. The combined results can tell if your baby has a higher risk of having Down syndrome, trisomy 18, and other chromosome disorders.

Quad marker screen. During the second trimester, your doctor or midwife can do this blood test. It helps show your baby's risk of Down syndrome or other chromosome problems and neural tube defects, such as spina bifida and anencephaly.  

If your tests come back normal, you may decide to stop there and trust that your baby doesn't have a neural tube defect or genetic disorder. Remember, a bad result doesn't mean your baby has a birth defect. It means your baby may have a higher risk. You may want to follow up with further testing to learn more.

Women over age 35 may skip screening tests and go directly to prenatal diagnostic testing.

Prenatal Diagnostic Tests

If results from screening tests raise concerns, or if you want further reassurance that your baby does not have certain problems, your doctor or midwife may suggest these diagnostic tests. Unlike screening tests, these tests are accurate ways of diagnosing problems. However, they do have some risks, including a slightly higher rate of miscarriage. You need to weigh the pros and cons.

Amniocentesis (called amnio for short). During an amnio, the doctor guides a very thin needle into your uterus and takes a small sample of amniotic fluid and cells to test. Amnio can spot chromosomal problems such as Down syndrome and trisomy 18. You usually have this test after 16 weeks.

Chorionic villus sampling (often called CVS). During CVS, your doctor takes a small sample of cells from the placenta to test for genetic disorders. This is generally done earlier in the pregnancy than an amnio.

Cordocentesis (also called fetal blood sampling). If the results of the amnio or CVS are unclear, your doctor or midwife may take a sample of blood from a vein in the umbilical cord to check for problems in your baby.

Tips for Taking Care of Yourself

Pregnancy puts extra demands on your body. When you’re older, these demands may increase even more. To maintain your health and the health of your baby, take extra special care of yourself no matter how old you are.

  • Get early and regular prenatal care.
  • Take prenatal vitamins every day that contain 0.4 milligrams of folic acid, which can help prevent certain birth defects.
  • Eat a healthy, well-balanced diet that includes a variety of foods. An average-weight woman needs to add only 300 calories a day during pregnancy. That's about a cup of low-fat yogurt, a medium apple, and 10 almonds.
  • Maintain a healthy weight during your pregnancy by gaining the recommended amount of weight.  These guidelines are based on whether you’re at a healthy weight, underweight, or overweight before you become pregnant. Of course, these are estimates. Check with your doctor about how much weight you should gain.

Weight status before pregnancy

Recommended range of weight to gain


28-40 pounds

Healthy weight

25-35 pounds


15-25 pounds


11-20 pounds