Week-by-week guide to pregnancy

group of pregnant women
When you're pregnant, you have lots of questions. Our week-by-week pregnancy guide is packed with lots of useful information. From what's happening inside your body, to how your baby is developing, and tips and advice on having a healthy pregnancy – this is your one-stop pregnancy guide!

Second trimester

Our week-by-week pregnancy guide is full of essential information. From staying fit in pregnancy to advice on your maternity rights, you'll find it all here. Happy reading!

Week 20 – your second trimester

You're halfway through your pregnancy now! Just 20 weeks ago, you were carrying on with your life as usual… and now you've got another human being growing inside you. You've come a long way. Enjoy the rest of the journey!

What's happening in my body?

You may have your anomaly scan this week. The sonographer will be checking on your baby's development and will also examine your placenta (that's the pancake-shaped organ in your body that feeds your baby and removes waste).

You might find yourself being woken up at night by sudden sharp pains in your calves. That's probably cramp, which is common in pregnancy. It's caused by muscular spasms, and it can feel like you're being stabbed in the leg for up to 10 minutes. Rub the muscle hard or pull your toes up towards your ankle. Exercising more in the day could help you avoid this and you could try these foot exercises.

Whooping cough jab

Whooping cough is on the rise – but you can protect your tiny baby from this dangerous condition by having a vaccination. The NHS recommends that all pregnant women should have the jab, ideally between 16 and 32 weeks. The immunity that you get will be passed on to your baby through the placenta and then offer protection until the routine jab that most babies have at two months. You don't have to have the vaccination – it's up to you. However if you'd like it, and haven't been offered it yet, talk to your midwife or GP. Find out more about the whooping cough vaccination.

Your Maternity Certificate

Ask your doctor or midwife for a Maternity Certificate, also known as a MAT B1 form. It's issued from 20 weeks onwards, and you'll need it to claim maternity pay and benefits – don't miss out!

Second trimester pregnancy symptoms (at 20 weeks)

Hopefully you're glowing with happiness and bursting with energy. However not everyone's the same, and you could be starting to get tired and even a bit grumpy as your body changes.

Your signs of pregnancy this week could include:

Tommy's, the baby charity, has a further list of common symptoms.

What does my baby look like?

Your baby, or foetus, is around 25.6cm long, which is the size of a banana. Measurements are now taken from head to heel. In earlier weeks, babies are measured from the head to the bottom because the legs are curled up and hard to see. Your baby weighs around 300g. That's approximately the weight of three juicy apples.

Your baby is now covered in a white, greasy layer of something called 'vernix'. It's thought that this protects their delicate skin from drying out in the amniotic fluid. This slippery layer also helps babies to make their way down the birth canal.

Your baby will be getting more active each day. As well as kicking, punching and turning around, your baby could be sucking their thumb – this develops their sucking reflex, which they'll need to suck milk once they're born.

You may start to feel a bubbling or fluttering in your pregnant belly – this could be your baby moving around.

Action stations

Maybe you know exactly what you're going to call your little one. But if you need any help with baby names, then check out websites online and have a bit of fun with the random name generators. How about Denver, Hervey or Ignatius?

This week you could also…

You don't have to tell your employer for several more weeks, but as soon as you do, you will have maternity rights and can attend antenatal appointments during paid work time. You can also ask for a risk assessment of your work place. If you want to wait, the latest you can leave it is 15 weeks before the baby is due, which is around week 25. It will probably be rather obvious by then anyway!

It's a good time to tone up those muscles 'down under'. Gentle exercises can help to prevent leakage when you laugh, sneeze, cough or jump around on your baby's future trampoline. Get the muscles going by pretending that you're having a wee and then stop the 'urine' in midflow. Visit Tommy's for more ideas.

Ask your midwife or doctor about online antenatal classes – they may be able to recommend one. The charity Tommy's has lots of useful information on antenatal classes and preparing you for birth.

Ask your partner if they would like to take part in the antenatal classes. Even if you've had children before, they're still worth going to as you can meet other parents-to-be. The NCT offers online antenatal classes with small groups of people that live locally to you.

Do your best to stop smoking, give up alcohol and go easy on the cappuccinos. We know that's easy to say, but hard to do. Ask your midwife or GP for support.

We can usually get enough vitamin D from sunlight, but between October and March it's best to take a vitamin D supplement every day. Just 10 micrograms is all you need (it's the same for grown-ups and kids). It's worth checking if you're entitled to free vitamins.

Get moving! It's recommended that pregnant women do 150 minutes of exercise throughout the week. You could start off with just 10 minutes of daily exercise - perhaps take a brisk walk outside. Check out Sport England's #StayInWorkOut online exercises (scroll to the pregnancy section). Listen to your body and do what feels right for you.

Don't eat for two! Eat for you. You don't need any extra calories until the third trimester, which starts in week 28. Try to eat healthily, with plenty of fresh fruit and veg, and avoid processed, fatty and salty foods. You may be able to get free milk, fruit and veg through the Healthy Start scheme.

This week's treat

Put your best foot forward… and go for a walk to unwind. Go solo, with your partner or with a family member. Walking keeps you fit, it's free and helps you avoid common pregnancy problems such as varicose veins and swollen feet.

Go back to week 19

Go to week 21

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