Week 31 of Pregnancy

Written by Amina Hatia RM and medically reviewed by Marley Hall RM

Published on March 1, 2022
Live & Online 60,000+ Community
At 31 weeks pregnant you are now into the 7th month of being pregnant – 7 months of changes and adaptations, watching your body change and your baby grow and develop! At this stage in your pregnancy, it’s an ideal time to start planning ahead – for the labour and birth and life with a new baby. If you haven’t already – 9 weeks before your due date is a great time to start antenatal classes, to find out how to start preparing for labour and birth, what happens in labour and what your choices are, as well as practical advice on life with a new baby. Our online antenatal courses cover all of this and more – and you can choose either a 4-week evening course, covering 8 sessions – or a weekend course if time is limited. Either way, both courses are midwife led, live and interactive and most importantly focused on ensuring you feel prepared and ready for birthing and looking after your baby and you. Finding out as much as you can – with your partner ideally, means you are prepared and feeling more confident about the labour and birthing process. However, you choose to have your baby and however your baby is born, we know as midwives that being involved, being able to make an informed decision, and being able to make the right choice for you results in a positive birthing experience. 

How big is my baby at 31 weeks?

Your 31-week baby is now around 42 centimetres tall if we were to measure from top to toe and the weight of a decent sized coconut at around 1.5 kilograms.

What happens in week 31 of pregnancy?

Baby is continuing to grow and get ready for the big world outside – you’ll be aware of this by how big your bump is! At 31 weeks, your baby’s eyes can now start to focus, rather than just be sensitive to light that has been the case since your second trimester. Once they have arrived, they won’t be able to ‘see’ in the way we as adults do – or track moving objects, which takes a few months after birth to develop in all babies. Baby’s brain is also working extra hard right now – making connections between nerve cells at an incredibly fast rate, by processing information, tracking light, and taking in signals from all their senses.

Week 31 pregnancy symptoms

Urinary Tract Infections (UTI) – Another common pregnancy symptom that many experience is UTI.  This is when your urinary system has become infected by bacteria. The reason why UTI’s are common in pregnancy is down to the hormonal changes happening in your body. Progesterone – that big pregnancy hormone, relaxes the muscles of the tubes which connect your kidneys to your bladder, slowing the flow of urine from your kidneys to your bladder. Due to this, bacteria has more time to grow before being flushed out – leading to a UTI. UTI’s can be resolved quickly if you get help as soon as you notice any symptoms such as:
  • Stinging or burning when you pass urine
  • Needing to go more often or very urgently
  • Pain in your back or lower abdomen
  • A high temperature
  • Shaking and shivering
  • Nausea or vomiting
  • Any blood in your urine
  • Feeling unwell
It’s worthwhile being aware that it is also possible to have a UTI without any symptoms. This is why your midwife will check your urine at every appointment and, if concerned, will send a sample off to be tested (with antibiotics offered if needed to clear the infection). An untreated UTI can make you feel very unwell, so getting help as soon as you notice any changes is important as UTIs can lead to:
  • Pre-eclampsia
  • Waters breaking early
  • Premature birth
  • Low birth weight
So if you are worried at all, speak to your midwife or GP for advice.

Week 31 pregnancy tips

  • Have you started thinking about your birth plan? It’s a great tool for working out how you feel about where and how to give birth, as well as options for managing labour such as pain relief.
  • There’s a lot of myths around labour, birth and pain relief and it can be hard to know who to believe. Get informed from trustworthy sources – our antenatal courses are written by midwives who are working in NHS hospitals and run by them too – always offering the most up to date, evidence-based advice honestly and in a clear way.
  • You may also want to start thinking of packing your bag for the hospital too – have a look at our FAQs on what to pack and why.

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