Week 40 of Pregnancy

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

Published on March 18, 2022
Live & Online 60,000+ Community

Congratulations – you have made it to 40 weeks and that estimated due date you were given probably right at the beginning of your pregnancy. As you are well aware by now though this doesn’t mean baby will definitely appear this week – the estimation is just that, and it’s important to remember that labour can start anytime between 37 weeks and 42 weeks.

This week can be quite an emotional time – the build up to the due date, the reality of going into labour, giving birth, and becoming a parent – can all cause anxieties and worries to really play on your mind.  This is completely understandable – but don’t let the worries overtake these last few days of your pregnancy either.

Find ways of relaxing and enjoying this precious time together – the final few days of pregnancy are a distinct time of waiting for the biological and psychological event of labour and birth. It’s a great time to practice some of the mind and body exercises we discuss in our antenatal course to help feel centred and in tune with your body.

Alongside all of the physical aspects of being 40 weeks pregnant – the heaviness, the discomfort of a baby engaged and low in your pelvis, back pain, peeing every five minutes and sleeplessness, there’s also the emotional and psychological aspects too. This is a unique time of being in between your old self and your new self, balanced on the edge of a pregnancy. It can be quite discombobulating, and you find yourself getting teary, nostalgic and emotional as you try to make sense of it all.

Whilst many will try and cheer you up and tell you ‘It’s nearly all over’ – try and give time and space to these feelings too. Don’t bottle them up or ignore them, they are important and valid too – and once you have acknowledged them, cried because of them, expressed your worries or sang, danced, shouted away the stress you will feel better.  Talk to others – your family and friends about how it’s all feeling, remind them you don’t need solutions just support right now.

And on a practical level there is still time for you, and your birth partner (if you have one), to learn about the aspects of labour and birth. You will have a 40 week appointment with your midwife sometime this week so make sure you put any questions you have to them and discuss how you are feeling too.

And above all – take good care of yourself, get out for gentle walks if you can, sleep and rest, be kind to yourself and don’t push yourself too much – emotionally and physically. This is a time for gentleness, a pause and quietness too.

How big is my baby at 40 weeks?

Every pregnancy and baby is unique, and how big or small they are will depend on a variety of factors, so don’t be too focused on the numbers!

On average by 40 weeks your baby will be measuring around 51 centimetres in length and on average will weigh about as much as a pumpkin, somewhere around 3.5 kilograms.

What happens in week 40 of pregnancy?

The majority of your baby’s development is complete, and baby is fully baked now!  Small changes continue – such any hair your baby has will continue to grow and become thicker or their nails will continue to grow too. 

Your baby now has all the skills and reflexes that will need to thrive once they are born, with of course lots of your love and care. You’ll notice these as soon as baby is born, from the first cry and gulp of air to the rooting babies do straight after birth looking for food, or the ability to grasp your finger tightly, which will also make your heartbeat faster with love and adoration.

40 pregnancy symptoms

Water’s Breaking – Water’s breaking is how most people imagine labour starts thanks to TV and films.  In reality it’s rarely like this – it’s not that common for your waters to break before your labour starts – so the big gush of fluid at the supermarket checkout we’ve all seen on TV is rare!  

Don’t be surprised if your waters don’t break until you are already in established labour – this is more common than your water’s breaking before labour.

Your water’s breaking may feel like a gush – some people report hearing a ‘popping’ sound just before the gush happens. You may also notice it as a stream of warm liquid that soaks your underwear and maybe even trickles down your leg.   

Alternatively, you may not be aware of your water’s breaking and initially think it may be urine leaking or extra vaginal discharge.  If this is the case, put on a sanitary towel and keep an eye out for a slow and steady trickle of fluid.

Regardless of how your water’s break – it’s important to let your midwife know as soon as possible – even if you are unsure. You’ll be asked questions about what time it happened, how you are feeling and what colour the waters are.

If you or your midwife think your waters might have broken but aren’t sure, you should be offered an internal examination. This will only be offered to you if it isn’t obvious your water has broken.

If your water breaks before labour has started and all is well with you and baby, you’ll be advised to stay at home and see if labour starts by itself – for most this will happen within 24 hours. If labour doesn’t start your midwife will discuss induction of labour with you and other options.

This is because your water breaking before labour starts increases your baby’s risk of infection.

You are also advised to avoid sex after your water breaks – so stick with a cuddle instead!

If you are waiting at home for labour to start you will be advised to contact your midwife if:

  • You have a high temperature
  • You notice a change in the colour or smell of your vaginal discharge or fluid
  • You feel your baby’s movements have changed or they are moving less. 

Week 40 pregnancy tips

  • If you haven’t already, you may want to consider adding a plastic sheet or some protection under your bed sheets to protect your mattress in case your water’s break.
  • Ensure your birth partner is aware of who to contact and when once labour starts and is prepared practically with enough fuel/ways of getting to the birth centre/hospital, aware of where to park if needed and your bag is already to go.
  • Have a review of your birth plan too – with your birth partner too in detail. If you have taken our antenatal courses, it’s a great opportunity to watch back the class recording we send out after every course to refresh your memory and help you feel better prepared.

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