The third trimester marks the final stretch towards your baby’s arrival. It can be hugely exciting, but also tough from time to time.

To help you navigate the final few months of your pregnancy, let’s run through how many weeks are in the final trimester, cover some of the most common late pregnancy symptoms, and answer some of the questions that parents ask about the third trimester.

How long does the third trimester of pregnancy last?

The third trimester lasts for 12 weeks.

When does the third trimester start?

The third trimester starts when the second trimester ends. It begins at the start of the 28^th week of pregnancy and ends when your baby is born.

Changes to your body in the third trimester

Welcome to the third trimester, it’s almost time to meet your baby!

Let’s cover some of the common third-trimester symptoms that pregnant people experience to help guide you through the final months.

• Acid reflux (heartburn): 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.
• 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 GP or midwife.
• Sleep troubles: You may find it harder to get comfortable in bed during the last few weeks of pregnancy due to your growing bump.

Third-trimester pregnancy belly 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.