What Happens in the 3rd Trimester?

Article By
Kate
Published On
19 Jul, 2023
Read Time
5 minutes

As you come towards the end of your pregnancy, you enter the third trimester, aka, the final stretch before your baby arrives. This is a significant and exciting time when lots of changes happen, and it's important to understand these last few months so that you can be informed and ready for birth.

So, let's take a closer look at what happens in the third trimester of pregnancy and answer some of the questions that expectant parents ask about the third trimester.

When does the third trimester start?

The third trimester starts when the second trimester ends. It begins at the start of the 28th week of pregnancy.

How long does the 3rd trimester last?

The third trimester lasts for 12 weeks or three months.

What changes to your body can you expect to see in the third trimester?

Entering the third trimester means that it's almost time to meet your baby - how exciting!

To help you know what to expect during these last few months, let's run through some of the common third-trimester symptoms that pregnant people experience.

  • Acid reflux: Heartburn during pregnancy is common in the third trimester.
  • Braxton Hicks contractions: Also known as 'false labour' contractions, these irregular contractions are felt at the front of your bump and are caused by your uterus muscles getting ready to deliver your baby. They last for under 30 seconds up to two minutes, while real contractions initially last between 30 and 90 seconds.
  • Breast tenderness: Your boobs may continue to change and become tender during the third trimester as your hormones adapt and prepare them for breastfeeding. Many pregnant people notice that their breasts change the most during the third trimester.
  • Difficulty sleeping: You may find it harder to get comfortable in bed during the last few weeks of pregnancy due to your growing bump.
  • Haemorrhoids: Also known as piles, these don't just happen during pregnancy, but they are common in the third trimester and are caused by hormones that make your veins relax.
  • Lightning crotch: This is a term commonly used by pregnant people to describe a sudden, sharp pain in the pelvic area. This pain is often felt in the lower abdomen and genital region and can be caused by the baby's head pressing against nerves or blood vessels in the pelvic area. While it can be uncomfortable, it is usually a normal part of the third trimester and not a cause for concern. Changing positions, stretching, or taking a warm bath can help.
  • Protruding belly button: During the third trimester of pregnancy, it's not uncommon for some women to experience a protruding belly button. This can be due to the growing uterus putting pressure on the abdominal wall, causing the belly button to push outward. While it may look unusual, it's usually nothing to worry about and is a normal part of the pregnancy process.
  • Shortness of breath: Your growing uterus puts extra pressure on your diaphragm in the third trimester and can make you feel short of breath. If you're worried about feeling breathless, don't hesitate to speak to your doctor or midwife.

Third-trimester pregnancy: how does your belly change week by week

Your bump will continue to grow and change shape throughout your third trimester as your uterus expands up towards your rib cage.

Your belly may shift downwards as your baby 'drops' into position in preparation for birth, but if your baby is breech - with their bottom or legs down and head up - your bump may be wider or slightly top heavy, and by the end of the third trimester, your bump will be at its biggest.

How does your baby develop in the third trimester

During the third trimester, a baby puts on weight quickly and their body gradually gets more in proportion. Their lungs mature, their eyes open and close, and they can distinguish between light and dark and may startle at loud sounds and sense changes in light. They'll continue to make lots of movements and usually turn into a head-down position by week 36, ready for birth.

Good signs to look out for in the third trimester

Feeling your baby move during the third trimester is one of the best signs that your pregnancy is going well at this late stage.

If you do notice your little one's movements changing and you're at all concerned, it's best to reach out to your doctor and they will be able to carry out any checks - such as a kick count - to confirm that everything's ok.

Advice for staying cool and comfortable throughout your 3rd trimester of pregnancy

Many pregnant people understandably find it harder to stay active as their bump grows bigger. During the final stages of pregnancy it's great to carry on gentle exercises like walking and it's also a great time to practice pelvic floor exercises or Kegels to help maintain muscle tone and prevent urinary incontinence.

Swimming can also help soothe aches caused by your growing bump and gives you a few minutes of feeling weightless.

Although it's great to stay active, as with any other stage of pregnancy, it's important to listen to your body during the third trimester and rest whenever you need to. Whenever you can, seize the opportunity to chill and do whatever helps you relax, maybe that's a warm bath, a pregnancy massage, or watching some TV while cradling your bump.

Third trimester FAQs

Third-trimester symptoms not to ignore?

It's normal to have worries as you reach the end of your pregnancy, but certain symptoms shouldn't be ignored.

You should seek advice from your medical care team as soon as possible if you have any of the following during your third trimester:

  • A fever above 37.5��C
  • Dizziness or blurred vision
  • Increase in vaginal discharge
  • Leaking of amniotic fluid
  • Noticing a decrease in baby's movements
  • Pain or burning when you pee
  • Regular contractions or tightening of the uterus before 36 weeks
  • Severe back pain or cramping in your lower abdomen
  • Severe headache or one that doesn't go away
  • Swelling in your face, hands, or fingers
  • Vaginal bleeding
  • Vomiting or nausea that doesn't subside  

We asked our Instagram followers what the third trimester felt like for them, and here's what they told us:

  • "A mix of feeling big, slow, excited, uncomfortable, nervous."
  • "Peeing 1000 times a day and tired."
  • "Tired and out of breath a lot."
  • "Nesting, waiting, and waddling."
  • "Tired, but some days I had a lot of energy."
  • "Long and uncomfortable."
  • "A marathon, never ever ending."
  • "The end feels so long, especially in the heatwave."
  • "Aching, tired, nervous, excited to meet baby."
  • "So quick, blink and you miss it."
  • "Walking feels like wading through a swimming pool."
  • "Long wait game full of excitement and anticipation."
  • "Different between both pregnancies, this one has been fine."
  • "Scared, energy low, puffy, exciting to meet the wee bundle."
  • "Heartburn was awful."
  • "Lots of aches, like your body doesn't belong to you."