Mumsnet pregnancy calendar

1st trimester

2nd trimester

3rd trimester

40 weeks pregnant


Your baby at 40 weeks

Baby at 40 weeks pregnant

Your baby is coming whether you're ready or not! She will look like an individual now and you will recognise her from other babies.

After 40 weeks she is ready to live outside your womb but do not expect her to be happy about it. Part of her crying will be in protest at all the noise and new sensations.

She will have to do things for herself that you did before - breathing, eating, regulating her temperature and going to the toilet. Be patient when she howls with misery and hold her close. However excited you are about having your baby, think of it from their point of view.

  • She will be about be about 3.5kg now and lovely and chubby. She will be whitish pink at birth - melanin does not get made until after your baby has seen light.
  • Her bones have become hard but her skull bones stay soft and pliable for passing down the birth canal, so they can overlap and she can get out. Because of this flexibility her head may have a cone appearance for a few days. The soft parts of her skull are called fontanelles. The front fontanelle becomes hard between the eighth and fifteenth months of life. The back fontanelle becomes hard earlier, between the third and fourth month.
  • As soon as she is born and takes her first breath a huge change occurs - the blood in her lungs will be oxygenated and she will breathe at a rate of 50 breaths a minute.
  • She will want to be held close to you. In the womb she had a limited area in which to thrash about, so she is more comfortable when she has a defined space. But don't swaddle her too tightly and always make sure her mouth and nose are clear and cannot get covered. She can't uncover them.
  • At birth she can see between 20cm and 30cm - the distance between your breast and your face.
  • In this scary, loud world that she's found herself in, you are familiar to her. Your heart beat and your voice have been her main sounds for months. 


  • It won't happen when you expect it to Only 5% of women give birth on their due day, so you're more likely not to give birth on the day you're most expecting to. Your baby is most likely to be born one week either side of it. Most babies come after rather than before their due dates. Try not to get too frustrated waiting - distract yourself and make plans for each day rather than staying at home just in case something happens. Even if you just walk round the corner to see a friend, you should get out and about. When you do go for a walk you'll still get short of breath because your baby still restricts how much your ribcage can move.
  • Read up about labour, but if you have decided on how you want your special delivery do not be disappointed if things don't go to plan. Do not feel guilty or a failure. There are no medals for bravery in pregnancy. You should never feel bad asking for pain relief. You are much more likely to bond well and quickly with your baby if your labour is not hideously painful, so the gas and air or epidural are for her as much as you.
  • Triggering labour There is no evidence for anything working but since you've got nothing else to do why not try: long walks, sex (sperm has prostaglandins, which are chemicals like the ones used in pessaries to induce labour) or nipple stimulation (this induces oxytocin, which can stimulate the uterus to contract, but research shows you would have to stimulate your nipple for an hour at a time). Raspberry leaf tea, curry and pineapple have all been suggested, as has acupuncture.
  • Don't worry if you don't feel overwhelmed with love for your baby as soon as you see her. Sometimes it can take a while. It doesn't mean you are not going to be a great mother.


This may be the final week in our pregnancy calendar, but we've got a child development calendar covering your baby's first year, so you can find about the milestones ahead for your baby - and you. Plus, we've got advice on your baby's feeding, sleeping, crying and more in our Babies advice pages.

And there's advice and support 24/7 on the Mumsnet Talk boards, so don't worry, you're not alone. 



Pregnancy Encyclopedia book coverIllustrations taken from The Pregnancy Encyclopedia, £25, published by DK.

Disclaimer: The information in the pregnancy calendar is for general information and is not intended as a substitute for the medical advice of your own doctor or antenatal team. Not all babies develop at the same time and in the same way, so this week-by-week guide may not always match your own experience. If you have any worries, consult your antenatal team or GP.

Last updated: 3 months ago