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Pregnancy health centre

31 weeks pregnant

WebMD Medical Reference
Medically Reviewed by Dr Rob Hicks


How is your baby growing at 31 weeks?

Your baby should now be about 42cm from head to heel and weigh around 1.6kg (3.5lb). There is still just a bit more of the finishing touches to get all the major organs fully functioning, but your baby's growth this week will continue to concentrate on increasing fat stores and muscle mass. Your baby's senses are also improving, and the completely opened eyes should now respond to light and dark, with the irises dilating and contracting. However, the eyes are not yet good at focusing unless an object – such as your baby's hand – happens to be quite close to his or her eyes. Put on some music and if your baby likes it (studies show they may have developed a preference for certain music by now), your baby may move to its rhythm. Not only should your baby be able to recognise your and your partner's voice, but possibly someone else's voice if you spend a lot of time with them.

You may have realised that your baby's movements have been getting increasingly active over the past several weeks, but around now they should begin to level off. Don't worry, there's still plenty of room for your baby.

How are you changing in week 31?

The increase in your bump and weight is likely to make you slow down. Listen to your body. If you feel the need to rest, find an opportunity to do so. If you have been trying to keep fit during your pregnancy, gentle exercise such as swimming or walking should still be fine. If you are experiencing breathlessness (with the baby moving up into the ribcage), gentle exercise is okay as long as it doesn't make you feel more out of breath.

If you haven't been feeling them before, you may now start feeling infrequent Braxton-Hicks contractions that last around 30 seconds. As long as they aren't regular, you'll know you are not going into labour too early.

During the third trimester 50–80% of mums-to-be will experience some type of swelling of their ankles and feet known as oedema. This occurs because of the pressure of the baby and womb on blood vessels, especially the inferior vena cava, which is a large vein on your right side that transports blood away from your legs. If blood becomes trapped in the legs, water is forced out of the blood and into the tissues of the feet and ankles, causing the swelling. The swelling typically gets worse towards the end of the day, but isn't as bad the next morning, after you've been sleeping. This swelling can affect the hands in the latter part of pregnancy, which can lead to tingling and numbness in your hands.

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