Third Trimester: What to Expect at 29 to 40 Weeks Pregnant


You’re nearing the end of your pregnancy journey, so here’s everything you need to know about your third trimester.

At 29 to 40 weeks pregnant you’re now in your third trimester and the final stages of your pregnancy. Your baby’s nearly ready to enter the world, and some of you might be ready wave goodbye to pregnancy, but there are still some key changes to your body and baby in this final stretch.

Your Baby in the Third Trimester

A lot changes in this last trimester. By 27 weeks, your baby can open her eyes and is about the size of a cauliflower. As you near full term, your baby will reach the size of a small pumpkin.

By the eighth month, your baby’s organs are pretty much fully developed. However, the lungs take a little longer and won’t be ready to breathe on their own outside the womb until around week 36.

Between 31 and 35 weeks your baby’s brain and nervous system will be fully developed and their bones will harden – except for the skull. At this stage, the furry lanugo hair is starting to shed from your baby’s skin, but the greasy vernix layer remains to protect their skin.

If you’re having a boy, by week 36 his testicles will have dropped from his abdomen to his scrotum.

The lungs and intestines should be fully formed by the final month. Ideally, from 36 weeks your baby should be head down in the uterus. If your baby is not in this position by this point, your midwife might suggest trying to turn the baby.

third-trimester-fetusYour Body in the Third Trimester

As we mentioned in both the first and second trimester, every woman’s pregnancy journey is unique, and although a number of changes take place in the final months, our body’s change in different ways.

In terms of weight gain, again everyone is different, however, if you are considered a healthy weight pre-pregnancy you should gain between 11.5 kg and 16 kg by full term.

For many women, the growing bump and swelling boobs can cause back pain. It might be time to invest in a pregnancy pillow, which can slot between your legs and lower back, to help with the sleepless nights. If that’s not quite cutting it, why not try a pregnancy massage to relieve some of the tension.

You might also notice that your body starts to swell in the final three months, particularly around the ankle, hands and face. As your baby drops, you may feel more pressure pushing on your bladder, meaning more trips to the loo.

Third Trimester Symptoms

Braxton Hicks

As you get closer to your due date, your body starts to prepare for labour. One way your body gets ready for birth is by keeping the muscles around your womb toned, though tightening and relaxing. These ‘contractions’ are often mistaken for labour pains, however, they usually last less than a minute and often ease off quickly. This is known as Braxton Hicks.

Braxton Hicks contractions can occur from around 16 weeks in the second trimester, however, the bigger your womb gets the more you’ll feel the muscles tightening. This means the sensation can intensify as you reach nearer to full term.

Here’s how to tell the difference between Braxton Hicks and labour contractions.

  • Braxton Hicks are infrequent and usually only happen a few times a day for a short period of time.
  • Labour contractions are often regular and last longer. They also increase in intensity as you’re closer to giving birth.
  • Braxton Hicks seem to be unpredictable and non-rhythmic. They ease off rather than increase in intensity.


The bigger you get, unfortunately, the more uncomfortable you might feel and the harder it might be to get a good night’s sleep. This can leave you feeling tired and exhausted during the day. Pregnancy pillows can help you get into a more comfortable sleeping position.

Shortness of Breath

Carrying around a growing human can also cause you to become increasingly short of breath in the late stages of your pregnancy


With more pressure on your legs and feet, you might notice your ankles swelling. Your face and hands may also swell slightly, too.

Bloated Tummy

As your baby grows, they’ll be compressing on your abdominal organs. This combined with the face your digestive system is slowing down, means it will take longer for your food to travel through your stomach and intestines. This can cause tummy pains and bloating.


Another side effect of your digestive system slowing in the third trimester is constipation.

Pre-Eclampsia Symptoms and Signs of Complications in the Third Trimester

While the symptoms listed above are common during pregnancy, at this late stage you want to keep an eye out for any signs of complications.

While swelling is normal, a rapid increase or change in your face, hands or feet could be a sign of pre-eclampsia. It’s also important to look out for the following:

  • High blood pressure
  • Severe pains beneath your ribs
  • Blurred vision and difficulty seeing
  • Strong headaches
  • Heartburn that can’t be treated with the usual medicines

Third Trimester Week by Week

Third Trimester Checklist

As you reach your third trimester, it’s time to thinking about a birth plan and getting your hospital bag ready. You might want to think about creating a checklist, so that you know you’ll have everything you need when the time comes.

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