Your pregnancy: A week by week fetal development guide

You won't believe how quickly they grow!

Having a baby is an amazing thing, and following your little one through their fetal development stages while you're pregnant (opens in new tab) is fascinating.

There's certainly lots to learn, so if you're interested in how your mini-me is growing then we've put together a guide to show you exactly how your baby is changing during their nine months inside your tummy.

From the first few weeks of fetal development, when your baby is technically a ball of cells, through their transformation to an embryo and right up until your little one's birth – this guide sees you through every week in confidence.

If you're having twins, we've included information on how they will develop, too, and the changes you can make to help give your baby (or babies!) the best possible support while they grow.

You'll learn all about how big your baby is growing during its fetal development stage, how much they weigh and all the things they're learning, too. There are some surprises along the way (like how early they get finger nails!) and some useful information on scans, check ups and appointments.

Click on the image below, depending on what pregnancy week you're currently in, to learn more…

Week by week fetal development guide

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How far along are you? We love hearing all your pregnancy stories, so if you’re expecting then leave us a comment in the box below telling us how you’re feeling, what stage you’re at and any tips you’ve got for fellow mums-to-be!