Structural Defects

Prenatal diagnosis means finding birth defects during pregnancy. There are three different kinds of birth defects and different tests to identify them.

Several different tests are available. This information, along with consultation with your health care provider, will help you choose which tests you want. Most likely all of the results will be normal, and you will be reassured.

Frequently Asked Questions About Structural Defects

What is a structural defect?

A structural defect is when a specific organ or body part has not formed normally. Some examples include:

• Heart defects
• Spina bifida
• Clubbed foot
• Cleft lip

Who is at risk for giving birth to a baby with a structural defect?

Most structural defects seem to happen randomly. However, some women have an increased risk, such as those with poorly controlled diabetes, a family history of structural defects, and those who are carrying identical twins.

How can you tell if my baby will have a structural defect?

We typically do two ultrasounds during pregnancy. The first one, at 11-14 weeks, can sometimes find structural defects. The second one, at 18–20 weeks, is specifically to find birth defects and is called a second trimester structural survey.

Do you recommend screening with alpha fetoprotein?

No. Maternal serum alpha fetoprotein (MSAFP) screening has been used in the past to help find spina bifida and certain other birth defects. Since we can find these using a second trimester structural survey, we no longer recommend this test.

Are there structural defects that cannot be found by ultrasound?

Yes, unfortunately, there are.

Is ultrasound covered by my insurance?

Most insurance policies will cover an ultrasound at 11-14 weeks as part of screening for chromosome defects (see below) and a structural survey at about 18 - 20 weeks. We recommend you check with your particular plan to understand your coverage and see if there are any out-of-pocket expenses. Our office can help by giving you the correct test code when calling your insurance company.

What may be done if my baby has a structural defect?

• We may recommend more tests, such as follow up ultrasounds, amniocentesis, or MRI. We often ask a pediatric cardiologist to look at the baby's heart
• We may recommend that you have an elective delivery, either by induction of labor or a planned cesarean section
• If your baby needs surgery or other special treatments right after delivery, you should give birth in a hospital that can provide those services
• In rare cases we try to correct the problem before birth
• You may want to make plans to help you care for your child after birth. It is often useful to meet with pediatricians and other specialists before the delivery. You may want to meet with other parents of children with similar problems
• Ending your pregnancy is also an option

Making a Decision

Before you agree to have a test, you should think about what you will do with the information. Many couples would not have a CVS or amniocentesis under any circumstances. They would not end the pregnancy if the baby is affected, and/or they do not accept the risk of miscarriage from CVS or amnio. These couples might not want to have screening tests.

Think about these questions before deciding to have any form of genetic testing:

• Is this information I want to know before delivery?
• How do I feel about ending the pregnancy?
• How do I feel about raising a child with a disorder?
• What impact will this have on my family?
• Who will care for an adult with special needs when I am no longer able?
• How do I feel about miscarriage?
• If I decide not to have testing, will I worry about this until the baby is born?

Remember that all of these tests are optional and entirely your choice. Discuss your options with your provider or a genetic counselor.