What to Expect During the Third Trimester
Taras Grebinets / Getty Images
Medically reviewed by Peter Weiss, MD
The third trimester of pregnancy is defined as beginning at 28 weeks and lasting until 40 weeks and six days of pregnancy. During this last trimester, your body will change as your fetus continues to develop and grow.
You may also experience different emotions, such as excitement, anxiousness, or feeling overwhelmed. Though most physical and emotional experiences are normal, some should be discussed with a healthcare provider.
This article covers what you can expect during the third trimester of pregnancy, including symptoms, prenatal appointments, and the importance of a birth plan.
Taras Grebinets / Getty Images
Last Trimester of Pregnancy: Third Trimester Changes
During the last trimester, the fetus grows and increases in weight, and its organs continue to
develop so they are ready to function after birth.
By the third trimester, the fetus can hear loud sounds, see changes in light, stretch, kick, and may turn so the head is positioned downward in preparation for birth. The fetus is considered full-term and fully developed at 39 weeks of pregnancy.
Since the fetus is increasing in size and taking up more room in the abdomen, you might feel uncomfortable, hot, have trouble taking deep breaths, and need to urinate more due to pressure on the bladder. You might also experience Braxton-Hicks contractions, in which the uterus tightens for 30 to 60 seconds as the body prepares for labor.
Other changes you may experience during late pregnancy include:
Increased tiredness and difficulty sleeping
Stretch marks and/or dry, itchy skin
Swelling of the ankles, hands, and face
An increase in white vaginal discharge (leukorrhea)
Backaches that may increase in severity
What Third Trimester Symptoms Are Unusual?
While there are many normal physical changes you might experience during the third trimester, you should contact a healthcare provider if you have any of the following:
Headaches with spots or flashing lights that do not go away
Sudden or extreme swelling
A decrease in fetal movement
Your water breaks, but you are not having contractions
Constant pain between contractions
Prenatal Appointments in the Third Trimester
At the start of this last trimester, you will likely start seeing your healthcare provider every two weeks, then once a week in the last month of pregnancy. During your visits, your healthcare provider might do the following:
Check your weight and blood pressure
Discuss any symptoms or concerns
Check your urine for sugar levels and albumin, a protein that can be a sign of preeclampsia
Check the position, growth, and heartbeat of the fetus
Perform a pelvic exam (usually around the 38th week)
Vaccines During Pregnancy
Flu, Tdap (tetanus, diphtheria, and acellular pertussis), and COVID-19 vaccines are considered safe for most pregnant people at any point in the pregnancy. They can help protect the mother and unborn baby from illness. Experts recommend getting a Tdap vaccine between the 27th and 36th week of pregnancy, keeping current on COVID-19 vaccinations, and receiving a flu shot before the start of flu season.
Third Trimester Birth Plan
The third trimester is a good time to start taking childbirth classes, especially if this is your first baby. You may also want to talk to your healthcare provider or find other resources to learn about breastfeeding.
Many expectant parents also find it helpful to create a birth plan. The plan can lay out important details such as who you'd like to be present at the birth, items that will help you stay comfortable during labor (such as clothing or music), and your wishes for pain relief. You should also discuss your plan with your healthcare provider and learn the policies and procedures of the site or setting where you’ll give birth to ask questions and ensure it aligns with your needs.
Although making a birth plan allows you some control over the experience, it’s important to remember that things don’t always go as planned when giving birth. Consider adding a section to your birth plan on your wishes if complications cause you to deviate from your original plan. Preparing in advance can help you remain calm if anything unexpected occurs.
Explainer
In the United States, most babies are born between the 39th and 40th weeks of pregnancy. In 2021 (the most recent year statistics are available), percentages of babies born at the following weeks of pregnancy were:
55.9% at 39 to 40 weeks
28.76% at 37 to 38 weeks
7.67% at 34 to 36 weeks
4.61 % at 41 weeks
2.81% at less than 34 weeks
Waiting Out Third Trimester Until Delivery
As your delivery date approaches, you may be on an emotional roller coaster, with feelings that might include being eager, anxious, overwhelmed, or stressed. These feelings are normal; you shouldn’t feel guilty or sad about having them. Taking care of yourself, eating well, getting enough sleep, and reaching out to family and friends when you need support are important.
Takeaway
If you are an expectant parent and anxiety or depression affects your daily life, or if you are experiencing panic attacks, mood swings, or overwhelming thoughts, contact your healthcare provider as soon as possible.
It can also be helpful to talk with other parents and to keep yourself busy. Consider making checklists to ensure you have everything you’ll need for the hospital (if that’s where you’re delivering), such as pajamas, slippers, and maxi pads.
You‘ll also want to make sure you’re prepared for when your baby comes home by having essentials such as diapers, formula (if you’re not breastfeeding or wish to supplement), baby clothes and blankets, and a car seat. It’s better to have these things ready in advance than buy them when you are busy with a newborn.
Summary
During the third trimester of pregnancy, your body will change as the fetus grows and develops. You’ll probably begin to see your healthcare provider more often for checkups. You may also feel a range of emotions, which is normal. Discuss any unusual symptoms or feelings with your healthcare provider. The third trimester is also a good time to take childbirth classes, learn more about breastfeeding, develop a birth plan, and get everything you’ll need for the newborn baby.
