Your pregnancy: 18 weeks pregnant

Last modified on Thursday 12 May 2022

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Find out what's happening inside you – and out – now that you're 18 weeks pregnant and firmly into your second trimester. Plus, this week you might be able to find out if you're having a girl or a boy at your anomaly scan appointment. Exciting!

What's happening at 18 weeks?

Here are the key things you can expect from your pregnancy at this stage:

  • Your baby has fingernails.
  • You may start sporting a proper bump around now if you haven't already.
  • You might notice some unpleasant discharge; always get it checked out.
  • Finding out the sex; you may be able to do this at your 20-week (anomaly) scan – see below (which can be carried out any time between weeks 18 and 21).

How big is your baby?

Your baby is now around the size of a doughnut.

Just when you thought your baby couldn’t put on any more of a growth spurt, you might be amazed to know that they've gained around 50g just since last week! This means your little one will be around 190g by the end of the week, measuring around 14cm from crown to rump.


Your baby's hearing has also improved, and may even be able to pick up you chatting to your bump, or when you're singing in the car or the shower.

It doesn't matter what you sing, or how well you sing it, either. Research has shown that newborns are just comforted by the voices with which they’ve become most familiar in pregnancy.

By now, your baby even has tiny fingernails and toenails at the end of their limbs. It's incredible to think that your baby is already so fully-formed! They just need to gain lots of weight now, plus their lungs are still developing; the lungs are one of the last parts of your baby to be ready for the outside world.

Your baby's genitals will now be formed and in place, and if you’re having a boy they might be visible during your 20-week anomaly scan. Read more about this scan below.

Doughnut with pink icing
Your baby will around be the size of a doughnut when you’re 18 weeks pregnant.

What's going on with your body?

Your tummy may have been getting rounder for a few weeks now (especially if it’s not your first pregnancy), but pretty soon it’s going to pop out into a proper bump.

Finally, people will realise you’re growing a baby in there, and haven't just put on a bit of weight!

A visible bump might also mean you start getting comments – even pats – from total strangers. While it can sometimes be nice to revel in the attention (and get a seat on the bus), don’t be afraid to politely ask people not to touch your bump if it makes you feel uncomfortable.

Your uterus is now about the size of a cantaloupe melon, and will have grown to as much as a thousand times its normal size by the time your baby is ready to arrive.

Try not to compare your baby bump with other women at the same stage of pregnancy. There are so many things that can affect the size and shape of your bump, including:

  • your pre-pregnancy size and shape
  • the size of your baby
  • the amount of amniotic fluid
  • whether this is your first baby or not (bumps tend to be a bit bigger and pop a little earlier with second and subsequent babies).

Your midwife will measure your bump at every appointment. If there are any concerns about your health or your baby's health, based on your bump size, your midwife should offer you extra scans to check that everything's OK.

So if your bump's a bit neater than your friend's is at this stage, or way bigger than it was last time, don't worry. As always, ask your midwife if you have concerns about how your pregnancy is going, but remember that there's a wide range of what counts as 'normal' when it comes to baby bumps!

What to expect this week: thrush

Ah the joys of pregnancy where the list of icky things just keep on coming. Another one to add to the growing list that can plague some unlucky mums-to-be is thrush.

Thrush is caused by a fungus called Candida albicans, which thrives in the vagina, usually causing no problems. In pregnancy, however, your changing hormones can affect the bacterial balance of your vagina, and this allows the fungus to multiply.

The result is a creamy discharge from the vagina, accompanied by itching and sometimes soreness. It won't harm you or your baby, but it can be unpleasant so it's always best to get it checked out.

It’s particularly common towards the end of pregnancy, but can strike in the second trimester, too.

If you're pregnant and you think you could have thrush, speak to your midwife or doctor. They'll be able to prescribe remedies that are safe to take during pregnancy.

Not all over-the-counter thrush remedies are safe to take while you're pregnant. In particular, don't take fluconazole while you're expecting. Always seek advice from a midwife, doctor or pharmacist before taking any medication while you're pregnant.

Remember, if the discharge is smelly or greenish, then speak to your GP again, as this could be the sign of a different infection that may require antibiotics.

If you still have thrush when your baby is born, the baby may catch it during the delivery. Although it won't do any harm, it will need to be treated.

What to do this week: get ready for your anomaly scan

Your next scan is called an anomaly scan, which is carried out any time between weeks 18 and 21 (it's sometimes also known as the 20-week scan).

It’s something to look forward to as this time you'll get a really clear view of what your baby is up to in there. However, the scan is there to look for any abnormalities, so it’s also perfectly natural to feel anxious about it.

The scan will be performed in the same way your dating scan was, using an ultrasound device and gel over your bump to get a 2D image of your baby.

Don't worry if the sonographer (who does the scan) isn't super chatty at first. They have to concentrate as they look for anything unusual in the baby's bones, heart, brain, spinal cord, face, kidneys and abdomen. They may even turn the monitor away from you while they get what they need.

Will I find out my baby's sex at the anomaly scan?

In most cases, yes: this is the exciting scan where you can find out if you're having a girl or a boy!

Bear in mind that it's not always possible though; if baby's moving around a lot, or in an awkward position, it can be hard for the sonographer to get a good look.

Some hospitals also have a policy of not revealing the sex. If you really want to know, it may be worth calling ahead to find out what your hospital's policy is.

Make sure you tell the sonographer if you don't want to find out the sex of your baby, too!

Can my partner or family come to the scan?

It's best to check with the hospital to see if your partner or another close relative or friend can come with you, just in case there are any concerns – although hopefully just to share in the excitement!

During the pandemic, some hospitals aren't allowing partners to attend ultrasound scans, as there's no way to safely accommodate another person with social distancing rules.

This can be tough for both you, and your partner or family. But remember that the rules are there to keep mums-to-be and their babies as safe as possible.

Your 18 week to-do list

1 Start collecting some loose change – you'll be visiting the hospital regularly for appointments from now on (and possibly more scans), so it'll come in handy for the car park. You may also need some to buy your scan photo!

2 Sing to your baby – not only is it comforting, it's a nice way to start bonding.

3 Start narrowing down baby names. Get inspiration by clicking below ...

4 If you found out your baby's sex, why not plan a cute gender reveal for friends and family?

5 If you haven't bought anything for your baby yet, now could be time to start getting a wishlist together. Browse our 100 best baby buys for inspo.

What to watch this week...

Get expert tips on what to expect at 18 weeks pregnant from our midwife.

What happens next week...

Want to know what happens when you're 19 weeks pregnant? Or do you need to remind yourself what you read last week? Click on the numbers above to find out more about what to expect when you're that number of weeks pregnant.

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