Third Trimester

What is the third trimester of pregnancy?

The third trimester consists of the final three months of pregnancy — or from weeks 28 to 40 (or until delivery). A pregnancy consists of three trimesters which each consist of roughly 12 weeks.

The final months of pregnancy can bring many physical and emotional challenges. It may be harder to get comfortable, and you may be balancing emotions like tiredness, excitement and worry. The third trimester is also when many people begin childbirth or lactation classes, and make sure they have baby items like a crib, diapers and clothing.

The third trimester of pregnancy is all about growth and preparation — for both you and the fetus. Your uterus is going to grow to about the size of a watermelon by the time the third trimester ends. You can expect to feel new symptoms like shortness of breath and Braxton Hicks contractions. The fetus will gain weight more rapidly and its organs will mature to prepare it for birth.

When does the third trimester of pregnancy start?

Most major health organizations agree that the third trimester of pregnancy starts at week 28. While there are slight variations depending on who you ask, most providers recognize 28 weeks as the start of the third trimester. The third trimester lasts until you give birth, which, on average, is weeks 39 or 40 of pregnancy.

Prenatal care in the third trimester

Your pregnancy care provider will schedule prenatal visits more frequently to check on the health of the fetus. Unless your pregnancy is high-risk, this typically means appointments occur every two weeks up until the 36th week of pregnancy. For the last four weeks of pregnancy, you go weekly. You should share any new or changing symptoms with your provider at these visits and ask them any questions you have. Like previous prenatal visits, they’ll check the following things:

• Your blood pressure.
• Your weight.
• The position and size of the fetus.
• Fundal height.
• Fetal heartrate.
• Your urine (pee).
• Your vaccinations. They’ll let you know about what vaccines are recommended for pregnancy.

Toward the end of pregnancy, some pregnancy care providers will check your cervix to see if it’s started to dilate (open) or efface (thin). Your provider will also complete a Group B strep test around 36 weeks to see if you carry the GBS bacteria.

If your pregnancy is high-risk or you go past your due date, your provider may recommend tests like a nonstress test or biophysical profile to check on the health of the fetus.

What are symptoms of the third trimester of pregnancy?

By the time you reach the last trimester of pregnancy, you may be feeling like a balloon that’s ready to pop. While everyone experiences symptoms of pregnancy differently, the third trimester is when most people begin noticing aches and pains a little more. Your body is still growing, and it’s preparing for labor and delivery — all at the same time.

You may notice all or some of the following symptoms in the third trimester:

• Braxton Hicks contractions: Unlike true labor contractions that get stronger, more intense and more painful over time, Braxton Hicks contractions are mild, irregular and don’t progress. They can feel more like menstrual cramps. Moving positions or walking can relieve them. Also, be sure to drink plenty of water.
• Shortness of breath: It can be difficult to take deep breaths in the third trimester. This is mainly because your lungs don’t have as much room to expand. This sometimes improves once the fetus drops down into your pelvis in preparation for birth (this is called lightening).
• Peeing more: When the fetus moves further into your pelvis, it can press on your bladder. This can lead to symptoms like peeing more often or leaking pee when you sneeze, cough or laugh. Contact your provider if you think you’re leaking amniotic fluid.
• Heartburn: Your growing uterus can press on your stomach and send stomach acids upward, causing symptoms like heartburn and indigestion.
• Swelling (edema): Fluid retention and weight gain can lead to swollen ankles and feet. Elevating your legs can help with the swelling.
• Varicose veins and hemorrhoids: An increase in blood volume can cause your veins to swell. This can cause spider veins on your arms or face or varicose veins on your thighs. Swollen veins in your rectum can cause you to develop hemorrhoids.
• Insomnia: Between the bathroom trips and discomfort from your belly, it can be hard to get quality sleep in the third trimester.
• Nesting: This is the strong urge to prepare your home (or life) for a baby. Some people say they experience a rush of energy that makes them want to clean and organize. It’s also OK if you never feel a nesting instinct — some people do, and others don’t.

It’s always OK to contact your pregnancy care provider if you’re unsure about a symptom. They can give you guidance that’s specific to you and your pregnancy.

How do I take care of myself in the third trimester?

It’s natural to feel tired and want to slow down in your final months of pregnancy. It’s OK if you don’t have the same energy you had earlier in your pregnancy. Try to do your best to move your body in a way that’s comfortable for you. Many people find walking, yoga or swimming feels best in the third trimester. Other things you can do to take care of yourself include:

• Eating nutritious, well-balanced meals.
• Drinking plenty of water.
• Asking for help when you need it. Your friends, family and partner(s) can help support you as your due date nears.

You should still avoid the following in your third trimester:

• Alcoholic beverages, cigarettes and drugs, and medication that aren’t prescribed to you.
• Raw or undercooked meat and fish high in mercury.
• Soft cheeses and unpasteurized dairy products.
• Hot tubs, saunas and steam rooms.
• Contact sports or activities with a high risk of falling.

Emotions during the third trimester

Beyond the things you notice physically, you may notice some emotional symptoms as your due date nears. It’s normal to feel excited but worried. You can still anticipate meeting your baby but have anxiety about giving birth or being a parent. Remember, everyone experiences pregnancy differently. There’s no right or wrong way to feel. If you need support navigating your emotions, reach out to someone for help.

How does my baby develop in the third trimester?

The fetus continues to prepare for its entrance into the world by growing in both length and weight. Its major organs are continuing to develop so that by birth, they’re fully functioning. Ideally, the fetus reaches full term before birth (39 weeks). The fetus gains more than half of its body weight in the last trimester. It typically moves to a head-down position, which is the best position for delivery.

Is my baby fully developed at 27 weeks?

No, a fetus isn’t fully developed at 27 weeks. Advances in healthcare make it possible for a baby born at 27 weeks to survive, but they’ll require significant medical intervention. Babies born prematurely at 27 weeks are at high risk for complications because most of their major organs aren’t fully functioning.

What complications can happen in the third trimester?

There can be complications in the third trimester. Some of the more common ones are:

• Preeclampsia: A condition that causes high blood pressure and other symptoms like protein in your pee.
• Gestational diabetes: A condition that causes high blood sugar.
• Preterm labor: Labor begins before the 37^th week of pregnancy.
• Premature (pre-labor) rupture of membranes (PROM): Your water breaks before labor begins.
• Intrauterine growth restriction: Your provider estimates the fetus is below the 10th percentile for its gestational age.
• Breech: A fetus is breech if its feet or butt is positioned to come out of your vagina before its head.

Your pregnancy care provider schedules more frequent checkups so they can detect potential complications. It’s important to attend all of your appointments and screenings to lower your risk of serious complications.

How do I know if labor is starting?

Recognizing signs of labor can be difficult, especially if it’s your first pregnancy. Some key signs of labor to watch for are:

• Contractions: If you’re in labor, your contractions get closer and closer together in frequency. For example, they come every 10 minutes, but then start to come every five minutes. They also increase in length of time, which means they may last 30 seconds at first, but then last 60 seconds. Finally, they increase in intensity or become more painful over time.
• Water breaking: This can feel like a sudden gush or slow trickle of fluid leaking from your vagina.
• Bloody show: Bleeding that occurs towards the end of pregnancy when your cervix begins to dilate is called a bloody show. Not everyone experiences a bloody show.
• Losing your mucus plug: Your mucus plug acts like a barrier between your vagina and uterus. Once labor begins, it can dislodge and come out of your vagina into your underwear. Sometimes, it comes out in one glob, but other times, you don’t notice it at all. This symptom doesn’t usually mean that labor is happening that day. Usually, the body is just preparing for labor, but everyone is different.

If you’re ever unsure about what’s happening, it’s best to be overly cautious and contact your pregnancy care provider.

When should I call my healthcare provider in the third trimester of pregnancy?

Communicating with your pregnancy care provider is more important than ever in the third trimester. Don’t be afraid to ask them what you can expect in the third trimester, including signs of labor and what symptoms could be signs of a problem.

You should call your provider if you have any of the following symptoms in the final months of pregnancy:

• Signs of preterm labor like painful contractions or your water breaking.
• Vaginal bleeding.
• A decrease in fetal movement. (How often the fetus moves can vary, but if you go longer than usual without feeling any movement, contact your provider.)
• Severe abdominal cramps.
• Nausea and vomiting.
• Dizziness and severe headaches.

Remember, it’s always better to be on the safe side and call your provider if you have a concern.

A note from Cleveland Clinic

It’s the third trimester and you’re in the home stretch of your pregnancy. It’s OK to feel a mix of emotions — discomfort, fear, excitement — as you near the end of this journey. Your body — and the fetus — will continue to change and grow in these last few months. You may even begin feeling tiny contractions or notice more vaginal discharge. Don’t worry; most of the time, it’s just your body preparing for labor and delivery. But, if you feel painful contractions or experience vaginal bleeding, contact your pregnancy care provider.

It’s also a good idea to ask your provider what you can expect in the final weeks of pregnancy. Asking questions and discussing your concerns with your provider will help you get to the finish line of pregnancy with confidence.