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20 weeks pregnant

Hang out the bunting – you’re halfway there! This week seems like an extra-big milestone, too, with your 20-week scan happening and the potential opportunity to find out if your baby is a boy or a girl.

By Mumsnet HQ | Last updated Jul 15, 2021

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Your bump at 20 weeks

I was huge at 20 weeks. My friend only looked about 20 weeks (slight roundness) the day she went into labour. People just carry differently.

By now, you're likely the proud owner of a definite bump – that you may still be able to hide with loose clothing. That'll keep the bump botherers at arm's length for a little while longer…

What size is the baby at 20 weeks?

Your baby smashes another milestone this week – from now, the professionals discuss her length in terms of head to heel rather than crown to rump, so if it seems like she’s had a sudden and miraculous growth spurt since last week, don't panic.

This week she’s around 16cm from crown to rump, or 26cm head to heel – about the size of a small banana.

Your baby's movement

As we mentioned last week, you might be starting to feel the first flutterings. They won't be enough for anyone else to feel just yet – they're just between you and her at the moment. In terms of what to look out for, sometimes it feels a bit like trapped wind, a twitch or, as one Mumsnetter said, “like the gloopy bubbles in a lava lamp reaching the top.”

Don't worry if you haven't noticed any yet, though, as the timing does vary from person to person. It could also be that your placenta is lying at the front, cushioning her acrobatics.

Your baby at 20 weeks

This week your baby is starting to ‘chunk up’ a bit, losing the slightly scrawny look she has sported so far and starting to lay down the fat and skin that will give her more of the ‘bonny’ look she’ll have at birth.

Her skin is thickening and developing layers so she won’t look quite so transparent any more. Skin is made up of an outer layer, the dermis, an inner epidermis (which is the thickest) and the subcutaneous bit, which is made mostly of fat, and it’s this part that is growing now.

You’ll get a good look at your baby at your anomaly scan. It takes a little while for the sonographer to carry out as there are all kinds of checks and measurements to do, so don’t panic if it feels like he or she has been peering at the screen for minutes without saying anything.

The scan will specifically look for the following problems:

  • Spina bifida – a condition in which there is an opening in your baby's spine because it has not fused shut.
  • Cleft lip or palate – where the roof of the mouth and the lips haven’t joined together properly. This is obviously very upsetting but can usually be fixed.
  • Diaphragmatic hernia – when the muscle between the baby's lungs and stomach doesn’t form properly.
  • Gastroschisis – a hole in the baby's abdominal wall, which means her bowel escapes and develops outside of the baby's abdomen.
  • Heart defects – the sonographer will check that all four chambers of the heart are working.

The sonographer will also do the following:

  • Check your baby's kidneys, brain and skull.
  • Measure your baby to make sure she is growing in line with her dates. They will check her abdominal and head circumferences, the length of her thigh bone and the distance between the sides of her head (known as the biparietal diameter).
  • They will also check the levels of your amniotic fluid and note the position of your placenta. If it’s still lying low, don’t panic, as placentas often move up when the uterus expands upwards.

20 weeks pregnant symptoms

As you get bigger, so do your ankles and feet, particularly if the last half of your pregnancy falls during the summer months.


If you suffer from swollen feet and ankles you might want to give a bit more thought to your footwear – something comfy and with plenty of ‘give’ is ideal. If the weather allows, flipflops may be your best option.

Putting your feet up as much as possible (higher than your heart if you can) and avoiding standing for long periods helps, too. You can also ask your partner to give your feet and legs a massage, gently ‘pushing’ the fluid back up the legs away from your feet.

Swelling is very common and usually nothing to panic about, but if you have other symptoms, such as sudden swelling of your hands and face, a severe headache, blurred vision or flashing lights, vomiting and feeling unwell or just ‘not right’, these can be symptoms of a potentially dangerous condition called pre-eclampsia. It’s rare to develop this before 20 weeks but can occur from now ( it is most common in the third trimester). If you do experience any of these symptoms alongside swelling, it’s important to seek medical advice right away.

How is your body changing at 20 weeks pregnant?

You’re onto the downhill strait now, having passed the halfway point. If you haven’t already felt your baby’s movements it’s likely to happen any time from now.

As well as the baby getting bigger, you’re gaining weight, too – about 0.5kg to 1kg a week in your second trimester. Obviously, a large proportion of this is the baby herself, but the placenta and the amniotic fluid also make up a fair bit of the extra weight, particularly by the end of pregnancy. Some is from your growing breasts and uterus, and about 2.5kg will be from fat that's laid down for you to use up in breastfeeding.

Weight gain is an inevitability in pregnancy but you do need to keep an eye on it as, if you put on too much weight, you're at risk of developing gestational diabetes. Eating for two is definitely not on the menu – your body doesn’t actually need any additional calories until the third trimester, and even then you only need about an extra 200 calories a day.

Things to think about during week 20 of pregnancy

The big news this week is obviously your anomaly scan, which happens between week 18 and 20 weeks plus 6 days. So much has changed since you last saw your baby on the 12-week scan and there’s much to think about.

Your 20-week scan

Until now your thoughts about the foetal anomaly scan have probably been focused on whether or not to find out the baby's sex, which is obviously a big deal. However, for the medics, the focus of this scan is all about whether everything is OK in there.

It’s completely normal to feel a bit anxious about this. The overwhelming likelihood that your baby will be fine. But even if she is fine, it’s easy to be freaked out by an offhand comment made about her size, the amount of fluid you've got or something that is difficult to see on the scan.

If you can, take someone along with you so that if you find yourself worrying later, you can ask them if they remember exactly what was said. In the scan itself, do speak up and ask if anything isn’t crystal clear – the sonographer will usually be able to set your mind at rest at once.

Dealing with annoying comments

Welcome to the second half of your pregnancy, when apparently it becomes open season on rude comments about how big you are, how small you are, how pointy, round or otherwise your bump is… Try to ignore any silly comments and don’t take them to heart. You can always ask when they got their medical qualifications (unless they happen to be a doctor, in which case they should know better than to make personal comments).

You can either give them a pained look or smile, depending on how much hatred you feel for them. Try not to shout abuse at them (unless they’re a repeat offender, in which case it might be fair enough). And if anyone is daft enough to combine a rude remark with a ‘bump pat’ you have our permission to let fly with the swear words or try any other means necessary to ward them off.

What Mumsnetters say

"I am twice the size at night than first thing in the morning, I measured myself last week. My bump is a great place to balance a Snickers bar!"

"You can hide a lot in there – I was amazed at the 20-week scan!"

"I'm 5ft 9 and slim. I felt like a complete fraud going to my 20-week scan. My bump appeared a couple of weeks later…"

"My 20-week scan was very similar in procedure to the 12-week scan, just longer and more detailed. They do lots of measurements, plot them on the computer, and check the heart, brain, other organs, arms and legs, and the gender if you want them to (we didn't). I think they also check the position of the placenta and the amniotic fluid levels."

What's next: 21 weeks pregnant