13 weeks pregnant: signs, symptoms and baby development

woman 13 weeks pregnant

by Emily Gilbert |
Updated on

Medically reviewed by Consultant Obstetrician and Gynaecologist Ms Ayanthi Gunasekera & Medical information lead at London Gynaecology

At 13 weeks pregnant, your placenta is fully developed and you can get ready to announce your pregnancy when you feel the time is right. You're now in month three of your pregnancy and have reached the final week of your first trimester and those unpleasant first trimester symptoms should begin to subside soon. Here’s what to expect during week 13 of your pregnancy, what's happening to your baby, what's happening to your body and symptoms you may be experiencing.

How big is my baby at 13 weeks pregnant?

Your baby has grown to about 7 cm long or the size of a lemon. The size of their head is much larger than their body at this point, but don't worry, the pace in which babies grow around this time varies very much from baby to baby so try not to compare yourself to other mums who might already be showing at 13 weeks.

lemon baby at 13 weeks

What’s my baby doing at 13 weeks pregnant?

At week 13, your baby has a lot going on, according to Dr Ayanthi, 'Your baby is becoming more active, moving around and even making tiny movements like sucking their thumb. They are also forming vocal cords, and their intestines are moving from the umbilical cord into their abdomen.'

Growing their body

At the moment, your baby’s head still makes up about half the size of their body, but the body will soon catch up with the head. During week 13, your little one will start developing bones in their arms and legs and the intestines will develop, which up until now have been growing inside the umbilical cord, but will now move to their permanent address in your baby’s abdomen. This week the placenta is also growing, and getting ready to feed and nourish your foetus for the next few months. Your baby will also now start developing his or her reproductive organs, but it’s probably too soon to see this on an ultrasound just yet.

Their eyes are still closed

Although their eyes are there, baby's eyelids are still fused shut to protect the eyes for the next few months while they still continue to develop.

Finding their voice

Another cute development this week – your little one’s vocal cords, something we’re sure they’ll use frequently once they're born!

What is my body doing at 13 weeks pregnant?

Things the body is doing at 16 weeks pregnant

It's normal to see and feel a lot of changes to your body in week 13 from easing up of symptoms to the first signs of a little bump. According to Dr Ayanthi, 'Your uterus continues to grow, and you may begin to show a noticeable baby bump. You might also experience changes in your skin, such as the appearance of the pregnancy "glow".'

Symptoms start to ease

As you reach your second trimester, symptoms such as morning sickness and exhaustion should begin to ease up. Don't worry if you're still feeling the symptoms into week 14 of pregnancy as some women find the fatigue and sometimes sickness can linger into months four and five.

Placenta is fully developed

By now, your placenta will be fully developed but will continue to grow in size throughout your pregnancy. Your baby is connected to it via the umbilical cord, through which your baby gets enough oxygen and nutrients. Yet the placenta also has an important role in getting rid of waste products such as carbon dioxide and producing many of the important hormones needed for your baby’s development. It might not be very pretty to look at (don’t Google image it if you’re still feeling delicate) but it does a truly amazing job for your baby.

Baby bump begins to show

This week, you might see the first signs of that baby bump – it usually shows up between 12 and 16 weeks, but this completely depends on your body and your baby. A showing bump can be one of the biggest pregnancy excitements and you can now get ready to announce you’re expecting.

13 weeks pregnant symptoms

While some familiar pregnancy symptoms might be sticking around this week, there could be some new ones you notice this week. 'As for changes to your body, you might start to notice a decrease in nausea and fatigue as you enter the second trimester.' Says Dr Ayanthi.

Pregnancy symptoms 13 weeks discharge

Changes in vaginal discharge

Otherwise known as leukorrhea, this thin, milky, mild-smelling or odourless discharge is another perfectly normal symptom, caused by the production of oestrogen during pregnancy. Its job is to protect the birth canal from infection and keep it healthy during pregnancy, so don’t worry about using special wet wipes to clean it away. The downside is it can cause a mess of your favourite underwear, so wear a thin panty liner around this time.

Increased energy

At last! Now the placenta is taking over, you should feel like you’ve got a bit more of a spring in your step. Consider using this energy and adding some pregnancy exercise to your routine, but don’t go mad!

Increased sex-drive

As your second-trimester approaches, you might find a boost in your sex drive during pregnancy! However, it’s worth noting if you’ve got a history of the early labour of miscarriage, it’s worth checking with your doctor beforehand.

Visible veins

You might not like them, but these are super important during pregnancy and are a sign of the increased blood supply to your growing baby. You may also notice changes in your skin texture and appearance such as slightly darkened patches of skin or even acne.


Heartburn in pregnancy is very common and probably won’t ease up any time soon. During pregnancy the muscle at the top of the stomach relaxes which allows digestive acid to rise and cause that familiar burning in the chest. Stay away from spicy or fatty foods and keep those antacids handy!


We’ve mentioned this before, but during pregnancy, those all-important hormones create some unwanted side effects, and pregnancy constipation is one of them! Your bowel muscles relax, meaning they are less effective at moving things along, which can leave you feeling pretty uncomfortable. Our top tips? Add some high-fibre snacks to your diet – fruit, vegetables and whole grains are good options.

Things to think about this week

As your pregnancy develops into the second trimester, there are a few things you might want to consider this week.

Pregnancy classes

Continue taking your prenatal vitamins

Dr Ayanthi recommends you don't skip your pregnancy vitamins and supplements to maintain a healthy pregnancy. Vitamins D and C as well as Folic Acid are particularly important to support your pregnancy.

Attend all your check ups

You should by now have had your first midwife appointment and may have had your 12 week scan. It's important you attend all your scheduled pregnancy appointments to ensure your pregnancy is developing as it should so keep your maternity notes safe and stay organised by putting all appointments in your diary.

Ensure you're eating a pregnancy safe diet

It's never been more important to eat a healthy diet to make sure you and your baby are getting those all important nutrients. You should also get to know what foods are not safe in pregnancy and keep this in mind when doing the food shop or eating out at restaurants. Also make sure you're staying hydrated and maintaining a moderately active lifestyle.

Consider what antenatal classes are available

Now is a great time to research the antenatal classes available in your area and speak with your GP or midwife to find out more about the classes they recommend. They'll help you learn more about your health in pregnancy, what to expect from labour and birth, pain relief options, relaxation techniques, birthing tools, help on feeding and caring for your baby, self-care after birth and more.

Could you be having twins?

If you find you’ve been showing for weeks and you’re already bursting out all of your clothes, it might be worth double-checking if you're pregnant with twins. If your first ultrasound has confirmed there’s only one little bun in the oven, do not worry, this could mean your due date isn’t quite right and you’re further along than you thought (or that you’re full of gas and are just bloated).

Tell work about your pregnancy

If you haven't already, now may be a good time to tell your work about your pregnancy. A lot of women usually leave this until their first scan at 12 weeks pregnant. Make sure you know your maternity rights once you've told them.

Start some pelvic floor exercises

Now is a good time to start toning and tightening your pelvic floor with some pelvic floor exercises which help prevent you leaking when you laugh, sneeze or cough.

About the expert:

Dr Ayanthi Gunasekera is a senior obstetrics and gynaecology (O&G) trainee (ST7) in North and East London at Barnet and Chase farm Hospitals NHS Trust. She has a keen interest in medical education and has a PG certificate in Medical Education.

Ayanthi has written patient information leaflets and guidelines and joins the London Gynaecology team as Medical Information Lead. In her spare time, she enjoys painting, gardening, knitting and crafting with her two young children.

A journalist since 2015, Emily Gilbertis the Features & Reviews Editor for Mother&Baby and has written for the website and previously the magazine for seven years. Emily writes about everything from the top baby products to pregnancy, fertility and maternal mental health. Specialising in product reviews, Emily is the first to know about all the exciting new releases in the parenting industry.

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