Third-Trimester Exams and Tests

Topic Overview

Routine exams and tests

At each prenatal visit, you can expect to be weighed and have your urine and blood pressure checked. Your health professional will monitor your fetus's growth and position by measuring the size of your uterus (fundal height) and feeling (palpating) your abdomen.

If your fetus is not in the head-down (vertex) position after 36 weeks (as confirmed by fetal ultrasound), your health professional may try to turn it gently from the outside (version). Version carries some risks, and not all health professionals are skilled in this technique. For more information, see the topic Breech Position and Breech Birth.

Late in your pregnancy, your health professional:

• Is likely to check you for group B streptococcus, which can cause severe newborn illness, disability, or death. This is done by rubbing the vaginal and rectal areas with a cotton swab. If you test positive for group B strep, you will be treated with antibiotics during labor.
• Will check to see how far the baby's head has dropped into your pelvis. Close to delivery, you may be checked to see whether your cervix has begun to stretch and open (cervical effacement and dilatation).
• May check you for hepatitis B. If you test positive for hepatitis B infection, your baby will receive the hepatitis vaccine and hepatitis B immunoglobulin (HBIG) within 12 hours of birth.

Additional testing

Experts recommend that all pregnant women be screened for depression during their pregnancy. Depression is common during pregnancy and in the postpartum period. If you have symptoms of depression during pregnancy or are depressed and learn that you are pregnant, make a treatment plan with your doctor right away. Not treating depression can cause problems during pregnancy and birth. To find out if you are depressed, your health care provider will ask you questions about your health and your feelings.

Later in pregnancy, your health professional may recommend an amniocentesis if there is a concern about infection in the amniotic fluid. Or the test may be done to check your baby for certain types of infections or other rare problems.