What do the standard prenatal tests check for?

At the first prenatal visit, a pregnant woman will receive a Pap test if it has been more than a year since her last one. The Pap test screens for precancerous abnormalities as well as sexually transmitted infections such as HPV, chlamydia and gonorrhea. A pregnant woman will also have blood drawn to check for blood type, immunity to hepatitis B and immunity to rubella (German measles) and syphilis. Additionally, many OB/GYNs will check for HIV and hepatitis C.

Doctors may perform other tests during pregnancy based on the woman's medical history and ethnic background. These include tests for cystic fibrosis, sickle cell and conditions that are more common among Jewish and other ethnic populations.

In the second trimester, the quad screen or amniocentesis is offered if appropriate. In the fifth month (around 20 weeks gestation), a detailed ultrasound is performed to look at the development of the baby. In the beginning of the third trimester (around 28 weeks), the screening test for gestational diabetes is performed. With the blood obtained during this test, other tests can be performed, including a repeat check for anemia.

Most insurance companies will only cover the cost of two ultrasounds in normal, uncomplicated pregnancies. Additional ultrasounds and/or further testing are based on the patient's history or any complications during pregnancy. For example, women who have a history of preterm delivery or are having preterm contractions may be offered fetal fibronectin testing.

Additional prenatal testing depends on the pregnancy itself. For example, a patient who is experiencing preterm contractions can be evaluated for preterm labor by ultrasound of the cervix as well as by the FullTerm test. For this test, a cotton swab is used to collect vaginal secretions. By evaluating the secretions, doctors can give women appropriate care or reassure them that they are not at increased risk for preterm delivery.