The Third Trimester of Pregnancy: How to Make Those Final Weeks Count!

6 minute read

Your Guide to the 3rd Trimester of Pregnancy

Your due date is getting closer and closer…It won’t be long until you are holding your precious new baby in your arms. 

But even though you only have a few more weeks left of your pregnancy, it can feel like time is inching forward. Especially if you start feeling anxious about your approaching due date or you experience unpleasant pregnancy symptoms. 

But, hang in there! Meeting your bundle of joy will make these final weeks worth the wait!

Here’s what to expect during your third trimester of pregnancy and how to make these last few weeks count!

When is the 3rd Trimester?

The third trimester of pregnancy begins as week 28 and lasts until the end of your pregnancy — usually 40 weeks. In total this last trimester is 13 weeks long. And it will span the last 3 months of pregnancy — from months 7 to 9. 

But your little one may come before or after their due date, which will affect the length of your third trimester.

Your body and baby have been through so much together, you’ll start to feel like your due date is just around the corner!

A Note About “Due Dates”: 

Real talk: Doctors and midwives calculate due dates by taking the first day of your last period as day one and the due date as 40 weeks from then. But, there’s only about a 4-5% chance your baby will be born exactly on their due date (Evidence Based Birth). 

It’s much more likely that your baby will be born somewhere between 38-42 weeks — this is the case for 80% of birthing people. 

About half of all pregnant people will go into labor on their own by 40 weeks and 5 days (for first-time parents) or 40 weeks and 3 days (for parents who have given birth before) (Smith, 2001). 

So even though your doctor provides a “due date…” For a lot of parents it’s actually more helpful to think of your baby’s estimated arrival date, as a range of time. That way you can be flexible, emotionally prepared, and ready for whenever your little one decides it’s time to join the world!

What to Expect in the 3rd Trimester for Your Baby’s Growth

While it may seem impossible that your belly could get any bigger… Your baby still has a LOT of growing to do in the third trimester. At 28 weeks they’ll weigh around 2.5 pounds at about 16 inches long. And by the time you deliver your little one around 40 weeks, they’ll weigh 6-9 pounds and be 19-22 inches long! 

Their weight will almost double in the 8th month alone. And in the last month of your pregnancy, your baby will be gaining around ½ a pound per week (American College of Obstetricians & Gynecologists)!

Your baby’s body will go through many major developments during these last three months:

• They can see and hear.
• They can suck their thumb and have the ability to cry.
• Their brain continues to develop.
• The kidneys and lungs continue to mature.
• Your baby develops vernix caseosa (or simply called vernix), a creamy, protective coating on the skin.

And just as you are starting to prepare for birth… So is your baby! Here are a few of the amazing ways your little one is preparing to make the delivery process as smooth as possible: 

• By the 36th week, the head may “engage” (drop into the pelvic area), a process called lightening, as they prepare to make their way into the birth canal. 
• Their head will usually turn downward during the last couple of weeks of pregnancy.
• The bones of their skull remain soft to make it easier to pass through the birth canal.

Weight Gain During the 3rd Trimester

During the third trimester you can expect to gain around 1-2 pounds per week. 

Here’s a helpful chart to help you determine how much weight is safe to gain for your body type (Institute of Medicine). This chart is based on your pre-pregnancy BMI (Body Mass Index) which you can calculate here (Centers for Disease Control). 

But you may be wondering, if your baby weighs 6-9 pounds by the time that they are born, where does the rest of that “pregnancy weight” go? 

Here’s an example breakdown (American Pregnancy Association): 

Average Pregnancy Weight Gain Chart:

• 7 1/2 pounds is about how much the baby will weigh by the end of pregnancy.
• 1 1/2 pounds is how much the placenta weighs.
• 4 pounds is increased fluid volume.
• 2 pounds is the weight of the uterus.
• 2 pounds is the weight of breast tissue.
• 4 pounds is because of increased blood volume.
• 7 pounds is maternal stores of fat, protein, and other nutrients.
• 2 pounds for the amniotic fluid.

Total: 30 pounds

Try to focus on eating healthy foods like grains, dairy, protein, fruits/vegetables, and healthy fats and oils. And limiting processed foods, sugars and extra fats can help you attain your health goals — and prevent unwanted pregnancy or birth complications such as gestational diabetes, preeclampsia, and cesarean delivery.

3rd Trimester Symptoms

The third trimester can be physically and emotionally challenging. You may feel tired, anxious, or simply uncomfortable! As your baby continues to grow and take up more space…it’s no wonder that you may have more trouble breathing or sleeping at night. 

Here are some of the most common changes and symptoms you may experience during the third trimester (John Hopkins Medicine): 

• Braxton-Hicks contractions (false labor) may begin to happen at irregular intervals in preparation for childbirth.
• Backaches may persist and increase in intensity.
• Shortness of breath may occur as your lungs try to accommodate your body’s new weight. 
• Constipation, heartburn and indigestion may continue.
• Spider veins, varicose veins, and hemorrhoids may persist and increase in severity. 
• Frequent urination may occur due to increased pressure being placed on the bladder.
• Leg cramps may happen more often.
• Increased body heat may happen as your baby radiates heat and increases your skin temperature. 
• Stretch marks may appear on the stomach, breast, thighs and buttocks.
• Swelling of the ankles, hands and face may happen (called edema), as you continue to retain fluids.
• Colostrum may begin to leak from your nipples.
• Dry, itchy skin may persist, particularly on the stomach, as the skin continues to grow and stretch.
• Skin pigmentation may become more apparent, especially dark patches of skin on the face.
• Hair may begin to grow on your arms, legs and face due to increased hormone stimulation of hair follicles. Hair may also feel coarser.
• Your libido (sexual drive) may decrease.
• Increased white-colored vaginal discharge may occur, which may contain more mucus.

Third Trimester To-Do’s:

As you near your due date, your to-do list may seem like it’s a mile long. But here are 5 important things that should make their way to the top of your list: 

1. Keep moving: Gentle exercise like walking, prenatal yoga, stretching, or pregnancy-safe exercises are great for both you and your baby’s health. Exercising will also help you build the strength you’ll need for labor! Check out some great exercise classes from one of our favorite groups Fit4Mom!
2. Keep up with your prenatal appointments: This will allow your healthcare provider to keep track of your baby’s development and take action if anything unexpected occurs. 
3. Get educated about labor, breastfeeding and postpartum: Take a childbirth education class, learn about the stages of labor, get connected with a lactation consultant, and start reading up on what happens after your baby arrives. 
4. Prepare for the hospital by packing your birth bag + writing your birth plan: These are the two most important “things” you’ll need to take with you when you’re ready to go to the hospital or birth center!
5. Choose your baby’s pediatrician: That way your little one will be all set for their check-ups in the first days and weeks after birth. 

Pro Tip: Make sure you have all the baby gear essentials — a crib, stroller, car seat, changing table and baby monitor. This will save you from any last minute runs to the store on the way home from the hospital — trust us, it happens! 

Shop the Babies in Bloom Boutique for a curated selection of parent-approved products. 
Not sure what you need? We’re happy to offer personalized instruction on how to use all products. You can call and schedule an appointment for this if you like, or we’re happy to meet you anytime during our boutique hours.