Mother and Baby

Week by Week

Whatever stage of your pregnancy journey you're at - congratulations on making it this far! 

From week 1 pregnant, when you might be pregnant without knowing it, through to week 42 pregnant, Mother&Baby is with you on your journey from bump to birth. 

We have expert guides on what to expect during every step of your baby's journey in your womb, with guides on what's happening to your body, all the information about pregnancy you'll ever need, the right foods and fitness advice, and the baby names you are planning for before baby arrives. Find all your pregnancy week-by-week information right here.

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You're pregnant! 

Now you're pregnant it's time to see just what's happening at every week of pregnancy! See an image of how your baby looks each week and click on the links below to learn what your baby and your body is doing, and what to expect. 
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Seven weeks pregnant 

Measuring about 1cm or half an inch, your budding bub is about the size of a blueberry. And wow, she’s busy – her ears, palate, tongue, tooth buds, nose, eye lenses are taking shape, as are the fingers and toes (which are webbed). The heart is really developing, along with the first blood vessels of the circulation system. And she’s starting to make little, jerky movements, too. You can’t feel a thing yet, but an ultrasound would pick it up.
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Eight weeks pregnant 

Your grape-sized baby has passed the embryo stage and can be officially called a foetus! And he’s really made progress – his spinal cord, bones and intestines are forming, his arms and legs have lengthened and there’s definition where his knees, elbows, wrists and ankles will be. His little chin will be tucked in and attached to his chest and – Einstein alert – his brain is developing into two different spheres. But despite this growth spurt he weighs a mere 1 gram (0.04 ounces).
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Nine weeks pregnant 

Up until this point, although your baby’s chromosomes are definitely male or female, the genitals were, well, ‘unisex’. But from week nine, he or she starts to form specific male or female genitalia. That’s not all – fingers and toes are growing (your baby even gets a tip to its nose and an upper lip). The head is still larger than the body due to all the brain activity. In fact you could even measure brainwaves at this point. As for size? Think ‘jelly baby’. Awww.
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Ten weeks pregnant 

Your baby is now one and a quarter inches (about the size of a prune) and can officially be referred to as a foetus! This week, you’ll notice your baby is starting to look more and more like a human, although she’s still got a huge bulge on her forehead as her brain develops. This week, her baby teeth will start forming under her gums, ready for that first smile! 
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11 weeks pregnant 

He might still be so tiny (at 4cm he’s smaller than your little finger and weighs in at 7 grams ¼ ounce) that he fits into the palm of your hand, but all his organs are formed, he has proper fingers and toes, a tongue with tastebuds, facial features and a hardening skeleton. So he’s starting to resemble a baby rather than a miniature (but adorable!) alien. His skin is still see-through and though his lungs aren’t fully formed yet, his heart is beating about twice the speed of yours. And he’s kicking and stretching like a prizewinning boxer, which he’ll keep doing 
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12 weeks pregnant 

All your baby’s body parts are present and she’s now officially a foetus in medical terms (although she looks like an adorable little alien!) Her intestines have moved into place in her abdomen. And your unborn baby will have developed the startle reflex, also known as the Moro reflex. This means she’ll hear sound and react to it by opening and closing her arms and legs. Probably not the time to freak her out with your banging collection of techno tunes.
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13 weeks pregnant 

She’ll start looking more and more like a normal baby, although her head will still appear proportionally pretty big compared to the rest of her body, and at about 7cm long, will still only weigh 23g. Your baby’s reproductive organs will be fully developed inside her body – she’ll already have – gasp - two million eggs in her ovaries. If you’re having a boy, his testes will be developed and his penis will be forming outside his body. However, even on an ultrasound scan, you probably won’t be able to tell the sex yet.
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14 weeks pregnant 

At 14 weeks, your baby is about 8.5cm long from head to bottom. Around now, she’ll start to swallow little bits of amniotic fluid, which pass into her stomach. The kidneys start to work and the swallowed fluid passes back into the amniotic fluid as urine. Although oxygen gets into her blood stream via the umbilical cord, your baby will also start practising her breathing which is important for when she’s born.
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15 weeks pregnant 

Around this time, your baby will start to hear muted sounds from the outside world; noises your digestive system makes (she finds the whooshing noises comforting, believe it nor not!); as well as the sound of your voice and heart. Talking or singing to her will help form a close bond. Her eyes will also start to become sensitive to light. Even though they remain closed, she can register a bright light outside your tummy, so if you’ve hit the beach in your chicest maternity bikini for some holiday fun, your baby will probably be aware of the sunshine hit.
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16 weeks pregnant 

The muscles of the baby's face can now move and she’ll start making facial expressions, although she won’t really have any control over them yet. She’ll also be able to move her limbs around and kick, even if you don’t feel anything. If you do, it will be more of a fluttering or ‘quickening’ sensation, which feels like butterflies in your stomach.
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17 weeks pregnant 

Your baby’s body is coated with hair called lanugo, which helps to keep her warm until she has laid down enough fat. She’ll also be covered in vernix – a waxy substance that protects her skin from the amniotic fluid that she’s floating in. When she’s born, you may see some of the vernix still on her skin, but your midwife will rub most of it off with a towel.
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18 weeks pregnant 

Whether it’s hiccupping, swallowing, sucking or doing acrobatic somersaults, your baby is already practising the vital movements that he’ll need to be able to do when he’s born (well, maybe not the somersaults). He’ll measure about 14-15cm from crown to rump and weigh around 200g.
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19 weeks pregnant 

Your baby’s eyes and ears are in their final position, although the eyes will still be closed. Fat is starting to develop on his body but he’ll still look quite skinny. The pigmentation in your baby’s skin is also beginning to develop, thanks to melanocytes – skin cells that produce the skin pigment melanin – and this will continue after he’s born and well into childhood.
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20 weeks pregnant 

Your baby is continuing to grow, especially his arms and legs, which will have lengthened in the last few weeks. Your baby’s internal organs, such as his lungs, digestive system and immune system are all growing and developing too and his bones are also getting stronger. Basically if your baby were to have an X-ray, his skeleton would show up more clearly because more calcium has been deposited within the bones. Help him along by including plenty of calcium-rich foods in your diet.
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21 weeks pregnant 

Measuring around 17cm and weighing about 350g, your baby’s brain is developing. The brain cells that have been programmed to control conscious thought are beginning to mature and research suggests that from this point onwards, your baby will start to develop a primitive memory. This means that playing your baby music now could soothe him after he’s born, because he will start to remember what he hears.
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22 weeks pregnant 

This week, your baby weighs in at 1lb and measures nearly eight inches – about the size of a bag of sugar (although it probably feels like you’re carrying a huge sack of it!) It’s around now that those little facial features are becoming more defined: she has tooth buds beneath her gum line, and, get ready for an ‘awww’ moment – her eyelids and eyebrows are now developed and those baby rosebud lips are also shaping up nicely.
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23 weeks pregnant 

By now your baby has started developing a noticeable sleep–wake cycle. There’ll be periods where he’s active and awake, and times when he’s asleep and resting. You’ll start noticing these different periods as his movements become clearer. And you may even be able to wake him up by your movements or by sounds around you. Watch out and see if bump moves if you have a warm bath or drink an icy glass of water.
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24 weeks pregnant 

Your baby will measure approximately 30cm and weight about 1lb 5oz – he’ll continue to put on about 3-3½ ounces per week until full term. Your baby’s lungs are maturing every day and they begin to produce a substance called surfactant, which helps to keep the alveoli (tiny air sacs in the lung) open. When he takes his first breath after he’s born, it helps to stop them collapsing, and your baby will practice the breathing action while he’s in the womb – moving his chest up and down and exhaling amniotic fluid.
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25 weeks pregnant 

Your baby’s hands will develop creases in the palms this week (cute!), and soon sweat glands will form in his skin. He’ll also have his own unique fingerprints – they will have started forming as early as eight weeks. Your baby will also be improving the dexterity in his hands and fingers, which means he’ll be able to grasp things in his fist and even play with his umbilical cord by pulling on it. He may suck his thumb and play with his hands and feet. Just think, not long until he’s gripping your finger in his little fist.
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26 weeks pregnant 

The heart rate of your baby will have slowed considerably by this week – from 180 beats per minute to 140-150 beats per minute – this can be monitored on a cardiotocograph (CTG) machine during your antenatal appointments and is a useful way of checking your baby’s wellbeing.
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27 weeks pregnant 

Blue, green, hazel brown… wondering what colour your baby’s eyes will be? Well his irises – the coloured part of the eye – will have started to develop pigment (melanin) now. Many babies are born with blue eyes (some will stay that colour) – because they’re still making melanin. Often the colour changes during infancy, going from blue to green, hazel or brown. The more melanin you have (which is dictated by your genes), the darker your eye colour. So it’s likely if you’re brown-eyed your bub will be too. But you’ll know for sure by the time your baby is around two years old.
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28 week pregnant 

Whether you’re singing along (badly!) to the radio, gossiping with friends or just chatting away to yourself, your baby will be able to hear it. In fact, the sound of your voice will help to calm him – studies have shown that your baby’s heart rate actually drops when he hears your voice. Bless! Encourage your partner to talk to your bump too – it’s a great way to start fostering a bond between them.
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29 weeks pregnant 

Now that your baby is much bigger, you’ll definitely start noticing kicks and wriggles. He may even kick when he’s asleep – just like you move around during the night trying to get comfy. There’s no set number of times that your baby should be moving – each child is different. However, if you notice that your baby hasn’t moved around for longer than you feel is normal, try to get him moving by drinking an icy cold glass of water. If that doesn’t work, call your midwife for advice.
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30 weeks pregnant 

By now your baby’s body parts will start to look more in proportion. The only exception is his head, which will still be quite large compared to the rest of his body. His fingernails will be fully developed and will continue to grow in the womb, meaning that when he’s born, they could be quite long and need cutting to prevent him scratching himself.
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31 weeks pregnant 

The size of a coconut, she’s around 16 inches long and weighs roughly three and a half pounds. Her digestive system, liver, kidneys and pancreas are functioning and her little body is plumping out with fat underneath the skin. She’s also extremely lively – wriggling, stretching and kicking so much now that you might even see your bump move – especially when you’re relaxing in the bath.
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32 weeks pregnant 

During the next seven weeks, your baby will gain a third to half of her birth weight. She’s even more acrobatic and may have turned herself into a head first position by now – although she still could flip around a fair bit before you give birth. There’s still about one and a half litres of amniotic fluid aiding your baby’s somersaults – but this will decrease as her size increases. At the moment she’s nearly 2kg (3-4 and a half pounds) and she’s 45cm (18 inches) in length.
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33 weeks pregnant 

While your baby’s bones are hardening, the ones in his skull are not fused together yet so they can move and overlap – which makes it easier for him when he’s squeezing himself through the birth canal (and explains why some babies are born with a slightly pointy head)! He’s managing to drink about a pint of amniotic fluid a day – which he urinates. The hair covering his body is starting to disappear, as is his red and wrinkly complexion. Now around 44cm, he weighs about four pounds and five ounces.
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34 weeks pregnant 

If your little one is impatient to arrive and pops out sooner than expected (i.e. now) it won’t be too dangerous for him as long as he’s not got any other health problems. He’ll have to stay for a short time in the neonatal nursery and may have a few health niggles, but generally he should end up as fighting fit as a full-termer. Oh, and right about now his first poo (meconium stool) is lurking in his intestines ready to be passed once he’s born. It’ll be thick, gooey and greenish black. Now there’s a lovely thought…
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35 weeks pregnant 

Now there’s less room to move around, your little one might actually start to push rather than kick. And if she does, you may even be able to see a teeny weeny foot imprint through your bump. Now she’s so close to being a fully functioning little human being, she’ll spend most of the rest of your pregnancy putting on weight.
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36 weeks pregnant 

At the end of this week, your growing tot will be considered full term – she’s now 6lb and 18 and a half inches long. Also her head may engage any time now (which means it drops into your pelvis). And some personality traits are already formed. Studies done on the heart rate and movement of 31 foetuses before and after birth have shown that the more active they were in the womb, the grumpier they are when they hit the world. Eek! By now your baby should be sleeping 60-80% of the time, but if she’s not, when she’s born she’s likely to sleep badly, too. These researchers suggest that it’s women’s hormones that influence personality traits in their babies. Their recommendation? That you take some time out before the birth so you can reduce your stress. And that you talk to your growing bump in a very soothing, calm manner.
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37 weeks pregnant 

Her vital stats? She weighs 6 1/3 pounds and measures a bit over 19 inches, head to heel. But, if she’s born now and has different colour hair to both of you don’t freak. It’s perfectly normal for dark haired couples to have a baby emerge with blonde or red hair, or fair-haired parents to have a little one with a dark mop to rival Harry Styles’. Alternatively, your baby could be a baldy and just have a fine peachy down.
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38 weeks pregnant 

Your baby is a fully functioning little human – still practising breathing and swallowing, though. If you’ve got a little boy, then his testicles have descended into the scrotum by now. And little girls might have slightly enlarged breasts (this is just the effect of your hormones and will go down after birth). Your placenta is also fully grown and weighs, gasp, 1 pound 9 ounces!
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39 weeks pregnant 

This might be your final week of pregnancy – but babies usually go past their due date (only 4% are born on time!), so don’t expect a prompt arrival especially if this is your first. You won’t be allowed to go past 10 to 14 days overdue – you’ll be offered an induction.
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40 weeks pregnant 

Your baby is full-grown and measures around 14inches from his head to his bottom. Babies at this stage weigh around 7½lbs, but this can vary massively. There’ll be hardly any lanugo on his body, except perhaps on his shoulders and in the creases of his body.
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41 weeks pregnant 

In the week or two before your baby is due, he’ll start shedding the greasy, white substance, which has been protecting his skin, called vernix. This turns the amniotic fluid, which was once clear, pale and milky. Overdue babies can be slightly larger than other babies as they’ve had longer to grow and their skull bones have had longer to fuse together. Both these things mean you have a slightly higher chance of having an assisted delivery with forceps or ventouse.
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42 weeks pregnant 

Babies that are overdue start to lose fat from all over their body so when they arrive they look a little wrinkled. Don’t worry, once he starts feeding regularly he’ll soon start putting the weight back on. They sometimes have long fingernails and toenails. Plus, some babies produce meconium (his first poo) in the womb, so his skin may have a slight green tinge, but this only really happens if you go over two weeks past your due date. Once again, this will all disappear a few days after the birth.

Check out mumfluencer Emily Norris' pregnancy journeys for a real-mum, down-to-earth guide to pregnancy. Emily has three boys under 8 and in this video she's edited together all her pregnancy updates for a full 9-month guide.

Video: Mumfluencer Emily Norris on her 9 month pregnancy journey

Your pregnancy guide, week-by-week

Mother&Baby, our experts and real mums are here to guide you every step of the way.

First trimester: 1-12 weeks

Second trimester: 13-27 weeks

Third trimester: 28-42 weeks

From week 1, when you might be pregnant without knowing it, through to week 42 - overdue! - M&B is with you on your journey from bump to birth. We have expert guides on what to expect during every step of your baby's journey in your womb, with guides on what's happening to your body, all the information about pregnancy you'll ever need, the right foods and fitness advice, and the baby names you are planning for before baby arrives. Find all your pregnancy week-by-week information right here.