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21 weeks pregnant

Now you're into the second half of your pregnancy, you're an old hand at all this. There are lots of exciting changes for your baby this week, but hopefully you should both be settling into the swing of things as well.

By Mumsnet HQ | Last updated Jul 16, 2021

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Your baby at 21 weeks

At 21 weeks your baby has been busy growing a fine hair called lanugo all over their body, which often disappears before they are born. His head and eyebrows are starting to show signs of pigment as they thicken at the roots, and his transparent skin is turning from pink to red, while his lips become more defined. Not only that, his eyelids have now formed and it’s possible for him to blink.

Another exciting development is the fact that your baby is starting to become quite a sophisticated individual with his own tastes and preferences – and even the basis for a memory of his own.

  • The food you eat changes the flavour of the amniotic fluid that he is swallowing on a regular basis – so if you eat a bar of chocolate now, he will taste it in a few hours' time – an excellent reason to buy a Galaxy Caramel, we think.

From dairy to meat and fish, there's a definite checklist of what you should and should not eat during your pregnancy, so make sure you also know which foods to embrace, and which to steer clear of.

Some research suggests what you eat now will influence your baby's food preferences after birth. But you should be guided by what you want to eat – don't feel you have to educate your baby's palate with a selection of foods from around the world each week – it may never pay off.

  • He is starting to absorb small amounts of sugar from the amniotic fluid that he is gulping down, but this is just his digestive system practising; he still relies completely on the nutrients he receives from the blood in the placenta.
  • This week your baby starts making red blood cells in his bone marrow (taking over from his liver). How sophisticated is that?
  • Your baby's memory is also beginning to develop. He won't remember being in your uterus (it's a pretty unmemorable location with very few landmarks, let's be honest) but he will find music familiar that he heard in utero once he's born, and will also be comforted by the sound of your voice, which he'll recognise from his days spent hanging out just below your vocal cords.
  • You will start to notice your baby moving around more than ever, and even establishing a waking and sleeping pattern – just don't expect it to always fit with yours.

Your bump at 21 weeks

Your burgeoning bump will start to threaten to eclipse the moon at some stage in the next few weeks – from about this point onwards your baby will start to outgrow your placenta for the first time. The placenta will continue to grow, but not as fast as your baby. On the plus side, this means you won't be able to see your thighs until after the birth. On a less glamorous note, it makes cutting your toenails and wiping your own bottom a bit of a challenge. On the toenail front, we advise you to get a nice pedicure. On the other front, well…. Just do your best. Or install a bidet.

Naturally, you will start to feel a little wobbly and unsteady on your feet due to your size. Make sure you take your time and if you do fall, don't worry! Your baby is surrounded by lots of cushioning to keep him safe.

What size is the baby at 21 weeks?

At 21 weeks, your baby measures 27cm from head to heel and is the size of a large carrot.

How is your body changing?

Despite the swelling, sweatiness and sensitive skin, all that extra blood volume and raised hormone levels do have one plus side – the famous 'pregnancy bloom'. If you're feeling less blooming and more bloody awful, try not to feel too murderous about it.

Some women look fabulous with the extra blood flow giving them plumped-out, rosy cheeks and extra hair growth bringing a gloriously thick and shiny mane. Others just seethe (and sweat a bit more than usual). If you're lucky you'll get the Timotei hair, healthy complexion of a shepherdess and be feeling sprightly and full of beans at all times… or at least until 9pm.

You may find this is the point that shoes stop fitting you. The softening of ligaments in the feet and extra weight you're carrying can mean your feet 'spread' and many women find that they go up a shoe size. As with your ribcage, your feet often don't shrink back to their pre-pregnancy size after the birth – so you might find you need a whole new shoe wardrobe. Shopping trip, anyone?

Pregnancy symptoms in week 21

Changes to hormone levels and also the amount of blood flowing around your body can make your skin more sensitive around this time.


Hormones, particularly oestrogens can give you itchy skin in pregnancy. This can be most irritating across your bump where the skin is more stretched than usual. Your palms and soles of your feet may be red and itchy, too, as they can get hot due to your higher body temperature and increased blood flow.

Something that cools the skin, like a cold, wet flannel, or an unperfumed emollient cream can help. Or you can always try putting a handful of porridge oats in an old stocking and hanging it from the tap while you run your bath. An oat bath is really soothing for itchy skin.

Itching is a pretty common pregnancy symptom, but if you feel itchy all over your body it can be due to an unusual condition called obstetric cholestasis, which is a problem affecting the liver that can lead to high bile salts being deposited in your skin, making it itchy. The condition can harm your baby so you need to tell your antenatal team if you have itching that is severe, particularly if it’s in the hands and feet.

Some women also experience increased oil production in their skin, which can cause acne.

Braxton Hicks

From about week 20 during pregnancy you may experience a tightening across your belly, a sensation which suggests you're experiencing Braxton Hicks. They're a type of contraction – not that kind – and usually fade between 20 minutes to an hour. But fear not – Braxton Hicks are uncomfortable rather than painful, and like morning sickness and all of the other pregnancy aches and pains, they're not harmful to you or your baby.


It's common to experience headaches during pregnancy due to hormones or dehydration. But if you have a bad headache that lingers for more than two or three hours, it could be a sign of pre-eclampsia, caused by high blood pressure. Speak to your healthcare advisor about the best course of treatment.

Bloating and wind

During pregnancy your uterus grows at an exponential rate – it reaches the size of a papaya during the second trimester – causing increased pressure on the oesophagus, leading to bloating and wind. Hormones also cause your digestion tract to slow down, which results in further wind and bloating – lovely!

Itching and bloating aren't the only symptoms you might not have expected. From an enhanced sense of smell to constantly needing a wee, there are numerous things nobody tells you about being pregnant. Luckily for you, you've got plenty of time to experience them all!

Things to think about during week 21 of pregnancy

A few things to think about (or perhaps just forget about) this week.


You may wonder if you have the 'right feelings' at this stage in your pregnancy. Do you want this baby enough? Are you relieved that your last scan was fine or has it made it so real that you feel anxious? Mumsnet has lots of posts from women who feel just like you, so head to the pregnancy Talk boards or your Mumsnet birth clubs and seek reassurance.

It's normal to feel unsure, anxious and unready, as well as excited. If you feel sad for prolonged periods of time, however, or hopeless about the future, then you should tell your antenatal team. Depression can often come on during pregnancy and midwife teams and GPs are trained to spot it and help you deal with it, so don't be afraid to ask for help.

What Mumsnetters say…

"My hair and nails are growing like mad, my skin is glowing, I've lots of energy and enjoy feeling the kicks. The second trimester is definitely my favourite so far!"

"I didn't even have a bump at 21 weeks (both times). My only 'symptom' was craving Mini Milk ice creams…"

"I go a bit funny if I don't eat regularly, including in the middle of the night. Otherwise, enjoying the vaguely nicer hair and skin but I haven't exactly turned into a model overnight. Not yet anyway."

"The bump is definitely getting there, but I can still more or less sleep in the recovery position. Rolling over wakes me up, though."

What's next: 22 weeks pregnant