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 28th 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.
Baby's growth and development 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.
Signs your pregnancy is going well 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 is ok.
Danger signs of pregnancy in your third trimester
It's normal to have worries as you reach the end of your pregnancy, but the major things to look out for during the third trimester are:
- 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
You should seek advice from your medical care team as soon as possible if you have any of the above during your third trimester.
