size of baby at 20 weeks?

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!

1st trimester
2nd trimester
3rd trimester

2nd 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.

Week 13
Week 14
Week 15
Week 16
Week 17
Week 18
Week 19
Week 20
Week 21
Week 22
Week 23
Week 24
Week 25
Week 26
Week 27

Week 20 – your 2nd trimester

You're halfway through your pregnancy now!
What's happening in my body?

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

You might find yourself being woken up at night by sudden sharp pains in your calves. It's probably cramp, which is common in pregnancy and caused by muscular spasms. 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 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 2 months.

Find out more about the whooping cough vaccination.

Maternity Certificate to claim maternity pay and benefits

Ask your doctor or midwife for a Maternity Certificate, also known as a MAT B1 form. It's issued from 20 weeks onwards. You'll need it to claim maternity pay and benefits.
2nd trimester pregnancy symptoms (at 20 weeks)

Your signs of pregnancy this week could include:

tiredness and sleeping problems (week 19 has information about feeling tired)
stretch marks (read about stretch marks on week 17's page)
swollen and bleeding gums (week 13 has information about gum health during pregnancy)
pains on the side of your belly, caused by your expanding womb (known as "round ligament pains")
headaches
nosebleeds
bloating and constipation (read about bloating on week 16's page)
indigestion and heartburn (week 25 talks about digestive problems)
sore breasts
leg cramps
feeling hot
dizziness
swollen hands and feet
urine infections
vaginal infections (see week 15 for vaginal health)
darkened skin on your face or brown patches – this is known as chloasma or the "mask of pregnancy"
greasier, spotty skin
thicker and shinier hair

You may also experience symptoms from earlier weeks, such as:

morning sickness (read about dealing with morning sickness on week 6's page)
weird pregnancy cravings (read about pregnancy cravings on week 5's page)
a heightened sense of smell
mood swings (week 8's page has information on mood swings)
a white milky pregnancy discharge from your vagina and light spotting (seek medical advice for any bleeding)

Read Tommy's guide to common pregnancy 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 3 apples.

Your baby is now covered in a white, greasy layer of "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 feed once they're born.

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

Action stations

This week you could: