Tommy's PregnancyHub

13 weeks pregnant - all you need to know

Welcome to the second trimester of pregnancy, a trimester of growth where your bump will get bigger and you’ll start to feel your baby moving.

What does my baby look like in week 13?

Your baby is growing fast - and you may be too! You might hear their heartbeat for the first time at your antenatal appointments.

Your baby now weighs around 25g.

Although you won’t be feeling baby move just yet, they're dancing around inside you. As time goes on their jerky motions are turning into slower, more purposeful ones.

Your baby’s hands find their way to their mouth and sometimes they look like they might be yawning or breathing. At this stage your baby only sleeps for a few minutes at a time but later in pregnancy, they’ll start sleeping for longer stretches and you might even notice a pattern, or routine emerging.

Your baby’s ovaries or testes have developed inside their body and a tiny willy or penis is now forming where a bump was before.

Get weekly updates on your baby's development from our expert midwives straight to your inbox.

Your pregnancy symptoms in week 13


Not all mums-to-be have cravings. If, however, you do - that’s normal. Cravings can be triggered by hormonal changes in your body affecting taste and smell. Also, sharp dips and peaks in your blood sugar levels can leave you hankering after sugary comfort foods.

These pregnancy snacks are great healthy options to get you through the day.

Take a look at our diet and nutrition guides on food swaps for a healthy pregnancy and how to have a balanced diet in pregnancy.

Feeling constipated or bloated?

Hormones can play havoc with your digestive system in pregnancy, leaving you constipated and bloated.

Do you have a headache? Perhaps you’re uffering from cramps, indigestion, dizziness, heartburn or swollen feet?

Here’s our guide to 10 common pregnancy complaints (and how to avoid them.)

What to do in week 13

Healthy eating

Having a balanced diet in pregnancy is important for you and your baby. Good nutrition will keep you healthy and help your baby grow and develop.

If you were struggling with sickness in your first trimester and this has now stopped, you may be feeling hungrier. Although you need to eat food that is good for you and your baby, you don't need to eat for two!

You only need to increase your calorie intake in the third trimester, and then, only by 200 calories a day.

Find out more about managing your weight in pregnancy.

Can I eat packaged salad during pregnancy?

If you buy prepared salad that is pre-washed, it's fine to eat as long as you make sure you keep it in the fridge and don't eat it after the use-by date.

Check the ingredients in any packaged salads you buy to make sure they don't contain foods you should avoid in pregnancy.

Staying active will give you energy

You may have felt a bit like sleeping more over the last couple of months - but hopefully those days are over. Now’s the time to get active again. It doesn’t have to be an organized exercise class, staying active by taking the stairs or walking to work, school or the shops really helps.

Being sedentary (sitting down a lot) in pregnancy increases your risks of complications so try to avoid this.

If you were active before pregnancy you can continue doing whatever you did before at a level that feels comfortable for you. Research shows that exercise is safe and healthy in pregnancy. Here’s our guide to staying active in pregnancy.

Your pelvic floor needs to be exercised for after the birth

If you haven’t already, this is a good time to start thinking about toning up your pelvic floor muscles.

Pregnancy and giving birth put a big strain on your pelvic floor - the more you can strengthen your muscles now, the better for the birth and after. Working these muscles will also help prevent you leaking wee when you laugh, sneeze or cough. 

You could do a set of pelvic floor exercises every time you brush your teeth, wait for a bus or put the kettle on.

Have you told your manager you’re pregnant yet?

You don’t have to tell your boss that you’re pregnant until the 15th week before the week your baby is due. It may be a good idea to tell them sooner though, especially if you have a strenuous job or need lots of check-ups early in your pregnancy.

“I work for a small company and two other women had announced their pregnancies just before me so I was really worried about how my news would go down, but everyone was so supportive.”

Rachael, mum of one

Read more about working in pregnancy.

NHS Choices. You and your baby at 13–16 weeks pregnant, (Page last reviewed: 28/02/2017 Next review due: 28/02/20207)

Lennart Nilsson (2009) A Child is Born, Jonathan Cape

NICE (2008) Antenatal care for uncomplicated pregnancies,Clinical guideline [CG62] Last updated: January 2017.

RCOG (2006) Recreational Exercise and Pregnancy: Information for you, London, Royal College of Obstetricians and Gynaecologists:

Review dates

Last reviewed: 25 June, 2018
Next review: 25 June, 2021