Week by week pregnancy guide: 40 weeks pregnant

Nearly there!

Prenatal depression

You're now 40 weeks pregnant but what should you expect? Read week 40 of our week by week pregnancy guide to find out everything you need to know...

Congratulations! You've reached the end of the road when it comes to your pregnancy week by week (opens in new tab) guide - well, maybe...

Pregnancy normally lasts about 40 weeks (that's 280 days from the first day of your last period), but only a fraction of babies arrive on their estimated due date. It can be dispiriting when your due date comes and goes without so much as a twinge, let alone a contraction, but try to keep busy and active! Here's everything you need to know when it comes to being 40 weeks pregnant...

Your maternity and baby care essentials 
Best maternity jeans (opens in new tab)Best maternity leggings (opens in new tab)Best maternity bras (opens in new tab)Best Moses baskets (opens in new tab)Best prams (opens in new tab)Best car seats for newborns (opens in new tab)

40 weeks pregnant: Symptoms

As your body prepares for labour your ligaments become very soft to allow your pelvis to expand. Your cervix also softens and thins and your placenta is now the size of a large dinner plate, 2-3cm thick and weighs a whopping 1lb 8oz.

Did you know, at the end of pregnancy much of the weight gained is roughly made up of the following:

  • Your baby - 7lbs 5oz
  • Extra blood - 3lbs
  • Larger breasts - 1lb
  • Enlarged uterus - 2lb 2oz
  • The placenta - 1lb 8oz
  • Amniotic fluid - 2lb 2oz
  • Retained water - 3lb 5oz

Read more: Signs of labour: Our guide on how to spot labour signs

40 weeks pregnant: Fetal development

40 weeks pregnant


Your baby is now about 50cm long and weighs about 7lbs 1oz. They are nearly 200 times heavier tan they were at 12 weeks!

If you do go into labour now the delivery process will kick-start their heart and respiratory system so they can live and breathe on their own.

40 weeks pregnant: The changes you should make

Go for a routine antenatal appointment.

Your midwife or doctor should give you more information about what happens if your pregnancy continues beyond 41 weeks. She will check the size of your abdomen, measure your blood pressure and test for protein in your urine.

If your pregnancy lasts another week then you may be offered a sweeping of the membranes (opens in new tab). A sweeping of the membranes is a method used to kick start labour and is usually tried before you are taken down a formal induction route. Your midwife puts her finger into the cervix to gently separate the bag of amniotic fluid from the side of the uterus near the cervix.

Once this separation has occurred, hormones are released which will hopefully encourage the natural onset of labour over the next day or so.