Trimester means 3 months. A normal pregnancy is around 10 months and has 3 trimesters.
Your health care provider may talk about your pregnancy in weeks, rather than months or trimesters. The third trimester goes from week 28 through week 40.
What to Expect
Expect increasing fatigue during this time. A lot of your body's energy is directed toward supporting a rapidly growing fetus. It's common to feel the need to reduce your activities and your work load, and to get some rest during the day.
Heartburn and low back pain are also common complaints at this time in pregnancy. When you're pregnant, your digestive system slows down. This can cause heartburn as well as constipation. Also, the extra weight you are carrying puts stress on your muscles and joints.
It is important that you continue to:
- Eat well -- including protein rich foods and vegetables frequently and in small amounts
- Rest as needed
- Get exercise or get a walk in on most days
Routine Prenatal Visits
In your third trimester, you will have a prenatal visit every 2 weeks until week 36. After that, you will see your provider every week.
The visits may be quick, but they are still important. It is OK to bring your partner or labor coach with you.
During your visits, the provider will:
- Weigh you
- Measure your abdomen to see if your baby is growing as expected
- Check your blood pressure
- Take a urine sample to test for protein in your urine, if you have high blood pressure
Your provider may also give you a pelvic exam to see if your cervix is dilating.
At the end of each visit, your doctor or midwife will tell you what changes to expect before your next visit. Tell your provider if you have any problems or concerns. It is OK to talk about them even if you do not feel they are important or related to your pregnancy.
Lab Tests and Ultrasounds
A few weeks before your due date, your provider will perform the test that checks for group B strep infection on the perineum. There are no other routine lab tests or ultrasounds for every pregnant woman in the third trimester. Certain lab tests and tests to monitor the baby may be done for women who:
- Have a high-risk pregnancy, such as when the baby is not growing
- Have a health problem, such as diabetes or high blood pressure
- Have had problems in a prior pregnancy
- Are overdue (pregnant for more than 40 weeks)
Checking Your Baby's Movement
In between your appointments, you will need to pay attention to how much your baby is moving. As you get closer to your due date, and your baby grows bigger, you should notice a different pattern of movement than earlier in your pregnancy.
- You will notice periods of activity and periods of inactivity.
- The active periods will be mostly rolling and squirming movements, and a few very hard and strong kicks.
- You should still feel the baby move frequently during the day.
Watch for patterns in your baby's movement. If the baby suddenly seems to be moving less, eat a snack, then lie down for a few minutes. If you still don't feel much movement, call your doctor or midwife.
Call your provider any time you have any concerns or questions. Even if you think you are worrying over nothing, it is better to be on the safe side and call.
When to Call the Doctor
Call your provider if:
- You have any signs or symptoms that are not normal.
- You are thinking of taking any new medicines, vitamins, or herbs.
- You have any bleeding.
- You have increased vaginal discharge with odor.
- You have a fever, chills, or pain when passing urine.
- You have headaches.
- You have changes or blind spots in your eyesight.
- Your water breaks.
- You start having regular, painful contractions.
- You notice a decrease in fetal movement.
- You have significant swelling and weight gain.
- You have chest pain or difficulty breathing.
Pregnancy third trimester
Gregory KD, Ramos DE, Jauniaux ERM. Preconception and prenatal care. In: Landon MB, Galan HL, Jauniaux ERM, et al, eds. Gabbe's Obstetrics: Normal and Problem Pregnancies. 7th ed. Philadelphia, PA: Elsevier; 2021:chap 5.
Hobel CJ, Williams J. Antepartum care. In: Hacker NF, Gambone JC, Hobel CJ, eds. Hacker & Moore's Essentials of Obstetrics and Gynecology. 6th ed. Philadelphia, PA: Elsevier; 2016:chap 7.
Smith RP. Routine prenatal care: third trimester. In: Smith RP, ed. Netter's Obstetrics and Gynecology. 3rd ed. Philadelphia, PA: Elsevier; 2018:chap 200.
Williams DE, Pridjian G. Obstetrics. In: Rakel RE, Rakel DP, eds. Textbook of Family Medicine. 9th ed. Philadelphia, PA: Elsevier; 2016:chap 20.
Review Date 6/2/2020
Updated by: LaQuita Martinez, MD, Department of Obstetrics and Gynecology, Emory Johns Creek Hospital, Alpharetta, GA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.