Your prenatal care visits will continue to include a number of available tests and procedures to monitor your health and the health of your baby. As always, make sure you talk with your health care provider and fully understand all that is involved before you decide to proceed with any procedure.

TRIPLE SCREEN TESTING

Note from Anthony Chin, MD: Some doctors have phased out this test in favor of the First Trimester Screening which now encompasses the nuchal translucency, PAPP-A, and hCG testing since it is more accurate and more sensitive. If so, s/he may recommend that you follow up your nuchal fold test with just an AFP screen (and not the other components of the triple marker screen) to rule out neural tube defects and SLOS (Smith Levli Opitz Syndrome).

However, not all doctors are certified to run these tests and order the accompanying blood tests. Unless your doctor sends you to a perinatologist to run a full first trimester screening, they might still rely on the Triple Screen Test during the second trimester.

What is it?

A blood test that screens for levels of three (or four) substances, determining your baby’s risk for certain chromosomal problems (such as Down syndrome) or neural tube defects (like spina bifida or anencephaly). Since this is a screening test and not a diagnostic test, this procedure estimates potential risk and is only an indicator that further testing should be done.

When is it performed?

Between weeks 15-20.

What does it look for?

The triple screen test measures the levels of the following:

1. Alpha-Fetoprotein (AFP): A protein secreted from the liver of the fetus that crosses the placenta into the mother’s blood.

2. hCG (human chorionic gonadotropin): A hormone produced within the placenta.

3. Estriol: Estrogen produced by both the fetus and the placenta. Who should have the procedure? Although it is not mandatory, the American College of Obstetrics and Gynecology (ACOG) recommends that the screening be offered to all pregnant women.

Why do it?

The triple screen test offers a non-invasive way to determine whether or not further testing should be considered.

Why wouldn’t I do it?

Even if your numbers fall in the “range” that suggests further testing be done, it doesn’t necessarily mean that anything is wrong with your baby. Even though the triple screen test didn’t pose any risk to your baby, these further tests can carry some risk. (These are all calculations that you need to take into consideration and make the decisions that are right for you and your family.)

AMNIOCENTESIS

What is it?

Amniocentesis is a procedure to check for genetic disorders like cystic fibrosis, chromosomal abnormalities like Down syndrome and fetal lung maturity. Since an amino analyzes genetic material, it can also tell you the gender of your baby with 100% certainty.

How is it done?

Using an ultrasound to find an empty area in the amniotic sac, a needle is placed through the abdomen to collect a sample of the fluid that surrounds the fetus. It takes about two weeks for results to come back, although you can opt for an additional FISH (fluorescent in situ hybridization) analysis which can return results for the most common problems within a few days.

When is it performed?

Usually between weeks 16-18.

Who should have the procedure?

Women who will be 35 or older on their due date, or are at risk for genetic or chromosomal problems. However, more and more women are opting for this procedure simply for peace of mind.

Why do it?

If you meet either of the criteria above, or your triple screen test results suggested further testing, taking the test may be something you’ll want to consider.

Why wouldn’t I do it?

Since it is an invasive procedure, amniocentesis carries a risk of miscarriage. It should be noted, though, that a November 2006 study published by ACOG showed that the risk of miscarriage was 1 in 1,600 – much lower than the 1 in 200 that is usually associated with this procedure. The difference in miscarriage risk is secondary to the experience of the physician.

Note: It’s important to find a doctor or technician who is experienced in performing amniocentesis (at least 50 a year). And make sure that you talk to your OB about risks and concerns.

ULTRASOUND

What is it?

Using high frequency sound waves, a gel is first rubbed on the woman’s belly, and then a transducer is moved across the belly, producing sound waves that bounce off bones and tissue, providing pictures of the baby (a sonogram).

When is it performed?

By this time, you might have already had an ultrasound to confirm your pregnancy, and possibly one during your first trimester screening. This trimester’s ultrasound is usually preformed between weeks 16-20. If your doctor uses the ultrasound machine sparingly, you can look forward to your next ultrasound at around 32 weeks.

What does it look for?

During this ultrasound, your doctor is continuing to check on your baby’s growth. S/he can also look for any congenital abnormalities. If you haven’t already had CVS or an amniocentesis, this ultrasound might give you your first glimpse at your baby’s gender.

Who should have the procedure?

Most pregnant women can benefit from an ultrasound at some point in their pregnancy.

Why do it?

An ultrasound can give your doctor the most accurate look at your baby’s development and growth – not to mention what’s going on with you. (Plus, most ultrasounds performed for medical reasons are covered by insurance.)

Why wouldn’t I do it?

When used correctly, ultrasound machines emit less energy than a fetal Doppler. However, if the ultrasound technician is not a physician or trained sonographer, it is wise not to risk exposure to an unknown level of sound waves.

This article was reviewed by Anthony Chin, MD. Dr. Chin is an OB/GYN in Beverly Hills, California.