Third trimester: Prenatal tests and screens you may be offered

Fetal fibronectin (fFN) test
A special swab will be used to take a sample of your vaginal discharge (like during a Pap test).

If you are having contractions, this test can help tell if your contractions are the kind that will cause your baby to be born prematurely. Fetal fibronectin is a glue-like substance that connects the amniotic sac around your baby to the inner wall of your uterus. If you are between the 23rd and 34th weeks of pegnancy and your health care provider finds fFN in your vaginal discharge, you are at increased risk of having your baby early.

Hemoglobin
Your blood is drawn and analyzed.

This test is for anemia and may show that you need more iron.

Non-stress test
Devices are placed on your abdomen to monitor your baby's heartbeat and your contractions.

This test gives your health care provider information about your baby's health and how the stress of movement affects your baby.

Group B streptococcus
Your vagina and rectum will be swabbed and the results cultured to see if you have strep.

Group B streptococcus (GBS) is part of the normal bacteria on the skin of 10 to 30 percent of American women. It does not cause illness in adults, but can cause devastating illness in newborns.

The Centers for Disease Control and Prevention recommends all pregnant women be tested between 35 and 37 weeks. If you test positive, have had a urinary tract infection with GBS during this pregnancy, or a previous infant with GBS disase, you will be treated with intravenous (IV) antibiotics when you are in labor.

If your water breaks or you go into labor before 37 weeks, before your test results are available or before you have been tested, you will also receive IV antibiotics. If you have questions, please ask your health care provider.