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Stages of Pregnancy – Third Trimester

You’ve made it to the third trimester! Your mind and body has been challenged, but you are strong and made to do this! During the third trimester, your baby continues to grow in size and weight. It’s almost time to meet your baby!


How Long is the Third Trimester?

The third trimester ranges from 28- 40 weeks, or until you give birth. Full term is considered 40 weeks. By the end of the trimester, your baby is about 20 inches long and weighs, on average, 7.5 pounds.

Your prenatal appointments increase from monthly to every two weeks beginning at 28 weeks, and then weekly after 36 weeks.

Baby Growth and Development

A protective layer on your baby’s skin that helps prevent drying of the baby’s thin skin is called vernix caseosa. This begins to form early in the third trimester.

Your baby will also be opening his or her eyes around 28 weeks. During the 30–34-week period, your baby has almost doubled its weight from the previous month. At 32 weeks, the baby is about 16 inches and almost 4 pounds, on average. From this point onwards, the baby’s weight will increase faster than its length.

You will be able to listen to your baby’s heart rate (normal is 110-160 bpm) during your visits and may also have an ultrasound scheduled to measure fetal weight and make sure the baby is growing on track.

As the lungs are still maturing, your baby begins to drop into the pelvic area, positioning itself head downward. By the end of the third trimester, your baby is about 19 to 21 inches long and weighs, on average, 6 to 9 pounds. In fact, your baby undergoes the most rapid gain in weight during the 36th week, gaining nearly half a pound a week until delivery.

Other exciting developments throughout the final trimester includes:

  • The ability to see and hear
  • The brain continues to develop
  • The baby can suck its thumb
  • The baby’s lanugo (soft hair on the body and limbs) has disappeared almost completely at around 38 to 40 weeks
  • The baby is covered in vernix caseosa (or simply called vernix) — a creamy, protective coating on the skin.

Changes to Your Body

You may start to feel more uncomfortable now as you continue to gain weight and begin to experience Braxton-Hicks contractions (false labor contractions). Some women find difficulty in taking deep breathes or getting comfortable enough to sleep.

At 28 weeks, your baby will be almost 15 inches long and weigh a little over 2 pounds.

Your bladder is under pressure due to the pregnant uterus and the rapid increase in the baby’s size can attribute to bladder problems for you. You may often find it difficult to hold your urine. In fact, it’s quite common for women to experience urine leakage during pregnancy.

Urinary tract infections can also occur, so it’s important to stay well hydrated with water and avoid caffeine, carbonated or artificial drinks. Kegel exercises can be helpful too.

Your estrogen levels will peak around 32 weeks. Due to this, you might notice some swelling around your ankles and feet, as estrogen is indirectly involved in making a pregnancy hormone related to salt and water retention. Similar to estrogen, your progesterone levels will peak around 32 weeks. This may cause some women to experience constipation.

Keys to a Successful 3rd Trimester

  • Sleep – Sleep is very important and in the third trimester. However, it may be challenging to find a comfortable position so try using pillows under your back and between your legs. This helps to relieve those pressure points.
  • Heartburn – You may notice an increase increase in the frequency and severity of heartburn. Try avoiding spicy, greasy foods, carbonated drinks and caffeine.
  • Vaccines – Educate yourself about vaccines. The Tdap vaccine is recommended in each pregnancy, preferably in the 12 weeks prior to delivery (28-40 weeks).
  • Birth Preferences – Start to think about your birth preferences by drawing up a birth plan that you can share with your OB/GYN or nurse midwife.

Last Month Pregnancy Concerns

One of the most common concerns in the last month of pregnancy is identifying labor symptoms and when to call your OB or hospital. One simple rule is 5-1-1.

If you have painful contractions every 5 minutes that last 1 minute for 1 hour, it is likely you are in labor. Other reasons to call are de­creased fetal movement and any bleeding or leaking fluid. Don’t worry, false alarms are common and nothing to be embarrassed about since not even the clinical team can predict labor.

As always, we are here to help you navigate through your pregnancy journey. Call us at 770.720.7733 with any questions or concerns or request an appointment online.

Learn what to expect in your 1st trimester and 2nd trimester.