Routine Testing in Pregnancy
By Dr. Peter Simonson
At your initial visit, you can expect a complete history and physical exam, a Pap Smear and cervical cultures, blood work and a limited sonogram to assess gestational age, number of embryos and viability. Risk assessment will be addressed.
Follow up exams are scheduled according to the individual risk of the pregnancy. Low risk patients are usually seen every 4 weeks until approximately 30 weeks at which point one is seen every 2 weeks. In the ninth month, exams are weekly. High risk patients are seen more frequently.
Patients will have the opportunity to have what is called a "first trimester screen." This involves an ultrasound exam to measure the thickness of skin behind the baby's neck (the "nuchal translucency") and specific blood tests. This combined test, i.e., the sonogram and bloodwork, can help to predict one's risk for having a child with Down's Syndrome or other such chromosomal disorders. If the test is abnormal, a more specific blood test can be done or a CVS (chorionic villous sampling) can be performed. Alternatively, a second trimester amniocentesis can be done.
All patients will have an opportunity to have the "Quad Screen," or what used to be called, "The AFP Test". The blood test is actually 4 tests (hence "Quad"), AFP, estriol, HCG and inhibin. The addition of the additional elements has increased the accuracy of the test. It is a test that screens for neural tube defects (problems with the baby's spine and brain) as well as for Down Syndrome (trisomy 21). The test is not perfect; an abnormal test does not mean your baby has a problem, and, unfortunately, a normal test result does not mean your baby is, necessarily, normal. If the test is normal, your baby probably has a much lower risk of having such an abnormality. If you had the first trimester screen, you wouldn't need a "Down Syndrome test;" you would be offered a single marker AFP test to screen only for the neural tube defects.
This is the time that patients are referred to one of the excellent radiology facilities in the area (including our office!) to have a formal ultrasound exam (a "sonogram"). During this exam, the anatomy of the baby and the uterine environment will be examined (fluid, placenta, umbilical cord, etc.). Some patients elect to find out the sex of the baby at this time, but many wait until delivery for the surprise!
Screening for gestational diabetes occurs at this time (the "sugar test"). While it is not necessary to be fasting for this test, the chance that your test will be abnormal is greater if you eat prior to the test. We, therefore, recommend that you either do this test first thing in the morning or in the afternoon without having eaten for about three hours. Drinking water prior to the test is OK. The test is done in the office, and if you are scheduled to see the doctor that day, you will be seen during your 1 hour wait that is required for the test. If the test comes back elevated, you will need to do a fasting 3-hour glucose tolerance test. This test would be done at a local lab.
If you are Rh negative and your partner is Rh positive, you will need a medicine called Rhogam to prevent an immune problem with this or future pregnancies. The doctor will have given you a prescription to pick up the Rhogam at your local pharmacy prior to the visit. The medication is given intramuscularly (arm muscle). It is usually given at the same visit that you do your gestational diabetes screen ("sugar test").
A genital culture for Group B Beta Strep (GBS) will be done at this visit. Approximately 20-30% of women in our community carry GBS as part of their flora (the bacteria that they normally carry). If you are a GBS carrier you should be given antibiotics in labor to prevent the baby from contracting Group B Strep disease (pneumonia, meningitis, encephalitis). If you were positive for "Strep" in a prior pregnancy, you will be recultured to see if your carrier status has changed, unless you had a baby affected by the bacteria, a positive urine culture for GBS in this pregnancy or if you go into labor prior to collecting the culture.