- Who is considered high risk?
- What tests do maternal-fetal specialists offer?
- I’m having a normal pregnancy. Do I need these tests?
- What if results of the ultrasound are abnormal?
- How can you detect problems other than chromosome abnormalities?
- How do I know if I’m at risk for pre-term birth?
You could be at increased risk for complications during pregnancy if you have cardiac or pulmonary problems, various rheumatologic disorders, diabetes, high blood pressure, or if you are over 35. You may also be at increased risk if you are carrying more than one baby, have a history of pregnancy-related complications, such as multiple miscarriages or pre-term birth, or have had babies with multiple complications.
In your first trimester, you’ll be offered nuchal translucency screening, an ultrasound technique that screens for Down Syndrome that’s combined with maternal blood test analysis. The ultrasound portion of the test measures skin thickness in the lower part of the head, where babies with Down Syndrome tend to have extra folds. When combined with blood screening, nuchal translucency testing can detect Down Syndrome with over 90 percent accuracy. The test can be used with twin fetuses, as well.A new test, the nasal bone test, looks for ossification of the nasal bone. Babies with Down Syndrome have delayed ossification and are more likely to have an absence of the nasal bone in the first trimester. The nasal bone screen, done during nuchal translucency testing, improves detection of Down Syndrome by another 5 to 8 percent. These tests are non-invasive and pose no risk to the fetus.
Marcy – “You truly care about each and every one of your patients and it shows in so many ways.”
All pregnant women, no matter what their age, should be offered screening with the nuchal translucency test. You’ll need a referral to a Maternal-Fetal physician and sonographer who is certified to perform each portion of the ultrasound screening. Certification to perform obstetrical ultrasounds (AIUM certification) as well a separate nuchal translucency and nasal bone certification (Fetal Maternal Foundation) has been shown to decrease false positive results and provide the highest level of accuracy to testing. Certified screening programs are usually found in specialized Maternal-Fetal Medicine centers of excellence.
If the results of nuchal translucency screen are abnormal, or if you want additional reassurance that your baby is healthy, you can have a test called chorionic villus sampling (CVS), done in the first trimester. CVS provides evaluation of the fetal cells for chromosome abnormalities very early in the pregnancy. This outpatient test, performed under ultrasound guidance involves passing a thin tube through the cervix or abdomen into the placenta to obtain a small tissue sample. CVS is similar to amniocentesis, which involves removing a small amount of amniotic fluid to evaluate fetal chromosomes. Since amniocentesis isn’t performed until the 16th week of pregnancy, CVS offers the advantage of earlier diagnosis.
The 4-D ultrasound, which provides a three dimensional image in real time, enhances your doctor’s ability to detect structural problems in the fetus, such as cleft lip and palate, skeletal problems, or limb abnormalities. An added advantage is the maternal bonding that the test promotes: You’ll be able to recognize the image as a fetus and see your baby’s eyes open and close.
Fifty percent of women who deliver pre-term have risk factors for the problem. The other fifty percent have no risk factors. Contractions may be the first predictor of pre-term birth, but they are often a false positive marker. So, for pregnant women who have risk factors or who start to have persistent and regular contractions, we objectively assess risk by measuring the length of the cervix with a transvaginal ultrasound or with a test for fetal fibronectin concentration, which involves a Q-tip placed in the vagina to measure the concentration of a protein that helps the fetal sac adhere to the uterine lining.If the test returns positive, you may need to be screened for vaginal infections, administered steroids to help the baby’s lungs mature and be monitored for contractions. You may possibly require medication to stop the contractions. If you have previously delivered a baby pre-term, you should consider taking the hormone 17 hydroxy progesterone, a new treatment given weekly starting in the second trimester until 37 weeks of pregnancy. This medication prevents 30 percent of recurrent spontaneous pre-term births. Additionally, high intake of omega-3 fatty acids in the diet or with supplementation may also help prevent a recurrence of spontaneous preterm birth in at-risk patients.