Women's

What to Expect: The Third Trimester of Pregnancy

Sep 15 • 2021
What to Expect: The Third Trimester of Pregnancy

Everything You Need to Know About the Third Trimester

If you’re in the third trimester of pregnancy—from week 29 to week 40—it won’t be long until your baby arrives. You may feel a mixture of tiredness, anxiety and excitement. Your emotions may be unpredictable, but the third trimester doesn’t have to be.

Dr. Charles Ryan, obstetrics and gynecology specialist with Cornerstone Women’s Center, recommends using these last few weeks to rest and enjoy time alone or with loved ones. As you move into this next stage and gear up for your due date, it’s also important to keep a few things in mind about your body and the baby’s development.

Changing Symptoms

With a new trimester comes new symptoms—and even some familiar ones. Morning sickness often disappears in the second trimester, but in the third trimester you may notice nausea start to return.

“It’s not morning sickness this time,” said Ryan. “Because the uterus is getting larger and pushing on the stomach, it may cause gastric reflux. While anti-nausea medicine worked for morning sickness in your previous trimesters, Pepcid Complete or an acid reducer will probably be the best thing for you in the third trimester.”

As the uterus grows larger, you may also feel shortness of breath because the lungs can’t expand as much as they did before.

Some people may develop preeclampsia in the third trimester. This is a condition characterized by high blood pressure, protein in the urine and other abnormal lab results. According to Ryan, the only way to get rid of preeclampsia is to deliver your baby.

“Preeclampsia is a serious, potentially fatal condition,” said Ryan. “If you have a persistent severe headache, abdominal pain, swelling or problems with your vision, call your doctor right away to have your blood pressure tested and to catch preeclampsia early.”

Weight Gain

“You’ll probably gain about half your pregnancy weight in the third trimester,” said Ryan. “Typically, weight gain of 25–35 pounds is recommended. Some people may gain more.”

A lot of weight in the third trimester comes from increased fluid retention. More fluid causes increased swelling in the lower extremities, which can be normal, but Ryan cautions against ignoring this symptom.

“Swelling can also be a symptom of preeclampsia,” said Ryan. “That’s something that you would want to talk to your doctor about as well.”

The Baby’s Growth and Position

The third trimester is an important growth phase for the baby.

“Your baby is growing and putting on weight,” said Ryan. “The lungs are the last thing to mature. They may not be fully mature until the baby reaches full term—so that’s why doctors don’t elect to induce labor before 39 weeks. We want to make sure the lungs are fully mature before that time.”

The third trimester is also the time when babies start to move into a downward position for birth.
“Typically, babies turn head-down by 36 weeks,” said Ryan. “We always check the position of the baby at 36 weeks, along with checking your cervical dilation.”

Don’t worry too much if your baby is still breech, or feet-first, around 36 weeks. According to Ryan, sometimes doctors can still turn the baby to a head-down position by doing what’s called an external cephalic version. However, doctors typically wait to see if the baby turns naturally, and if not, usually deliver by Cesarean section.

Safe Workouts

Regular exercise can help relieve some discomfort you may feel in the third trimester of pregnancy. People with certain pregnancy problems should avoid certain workouts. You can talk to your doctor about exercises that are right for you.

“Some people don’t know that yoga can lower stress and improve the quality of your sleep,” said Ryan. “Walking and swimming can also be good cardio activities. Try to get at least 30 minutes of exercise per day.”

Red Flags

One of the main things to watch out for in the third trimester, said Ryan, is premature or preterm labor. This is when your body starts getting ready for birth too early—usually around three weeks before your due date.

“Up until 36 weeks, if you’re having contractions that are closer than 10 minutes apart and last for an hour, you should get checked out at the hospital or in the doctor’s office. Acting fast can make a big difference, and doctors can do things to delay an early delivery.”

In addition to preterm labor, you should also be aware of decreased fetal movement toward the end of the third trimester.

“Babies are running out of room, and the fluid around the baby is decreasing as well,” said Ryan. “From about 36 weeks on, you may feel squirming rather than big kicks. This is normal. But any prolonged, decreased fetal movement should be checked out by your doctor.”

Taking a Childbirth Class

Childbirth classes can help reduce fear and anxiety while increasing your confidence about labor and delivery.

“The more information you have, the less scary birth can be,” assured Ryan.

Childbirth classes through Baptist-DeSoto teach about breathing and visualization techniques, different modes of pain relief, what’s going to happen when you go into labor, as well as newborn care and breastfeeding versus bottle feeding.

“If you take some of the mystery out of it, it’s not as tense or nervous of a situation,” said Ryan. “Childbirth classes can really help demystify the process.”