Trimester means 3 months. A normal pregnancy is around 9 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.
Expect increasing fatigue during this time. A lot of your body's energy is directed towards supporting a rapidly growing fetus. It's common to feel the need to reduce your activities and your work load, and 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. 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 doctor or midwife 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, will:
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 doctor or midwife 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 doctor 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
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 health care 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 health care provider if:
You have any signs or symptoms that are not normal
You are thinking of taking any new medications, 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
Gregory KD, Niebyl JR, Johnson TRB. preconception and prenatal care: part of the continuum. In: Gabbe SG, Niebyl JR, Simpson JL, et al, eds. Obstetrics: Normal and Problem Pregnancies. 6th ed. Philadelphia, PA: Saunders Elsevier; 2012:chap 6.
Williams DE, Pridjian G. Obstetrics, In: Rakel RE, ed. Textbook of Family Medicine. 8th ed. Philadelphia, PA: Saunders Elsevier; 2011:chap 21.
Cynthia D. White, MD, Fellow American College of Obstetricians and Gynecologists, Group Health Cooperative, Bellevue, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.