12 weeks pregnant: ultrasound, bump and symptoms

12 weeks pregnant scan

by Emily Gilbert |
Updated on

Medically reviewed by Consultant Obstetrician and Gynaecologist Ms Ayanthi Gunasekera

So, you’re 12 weeks pregnant, but did you know that your little one has more than doubled in size over the last few weeks? Yep, your body is going through some really exciting changes!

Here’s what to expect during week 12 of your pregnancy, what happens during your 12-week scan and everything else you could possibly need to know about hitting the second trimester...

Your baby at 12 weeks pregnant

"At 12 weeks pregnant, your baby is approximately the size of a plum," says Consultant Obstetrician and Gynaecologist Ayanthi Gunasekera. "The length from the crown (top of the head) to the rump (bottom) is typically around 5.4cm."

"Most major organs are fully formed, and they continue to mature and function." Their intestines have moved into place in their abdomen. Your little foetus will now enter the maintenance phase; for the next 28 weeks, their systems and organs will develop so they are ready for life on the outside. Their digestive system is beginning to start practising (literally) and their bone marrow is busy making white blood cells. "The umbilical cord is fully functional, providing the baby with nutrients and oxygen," says Ayanthi.

This week your unborn baby will have developed the startle reflex, also known as the Moro reflex. This means they'll hear sounds and react to them by opening and closing their arms and legs. This is the time to introduce your little one to your favourite music! "While you won't feel it yet, your baby is moving around," says Ayanthi. You can expect to feel this along with kicks later on in the second trimester.

Another exciting moment this week will be the 12-week scan, and seeing your baby’s heartbeat for the first time. Scroll down for more information on what to expect during that scan.

Your body at 12 weeks pregnant

As your uterus moves from the bottom of your pelvis to the front of your abdomen, you’ll hopefully (finally) lose the need to constantly wee! That said, you might start feeling dizzy as a replacement, as progesterone causes your blood vessels to relax and widen to increase the flow of blood to your baby.

Remember, if you feel dizzy or faint, lie down with your head lowered between your knees, take deep breaths and keep snacking to keep those blood sugar levels up.

You may experience some more positive changes too. "Some women notice changes in their skin, such as the 'pregnancy glow' or darkening of the skin in certain areas," explains Ayanthi. "Hair and nails may grow more quickly and become stronger due to hormonal changes."

12 weeks pregnant belly

Your pregnancy won't be showing just yet, but that's okay. It’ll push itself above your pelvic bone soon, so expect the first vague outlines of a baby belly. On that note, your jeans, trousers and skirts are probably becoming quite snug, so it might be time to invest in some comfy maternity clothes.

12 weeks pregnant symptoms

Morning sickness

"For many women, morning sickness may begin to decrease or subside by the 12th week," says Ayanthi. However you may still be experiencing morning sickness at 12 weeks pregnant and if so, keep eating little and often and stay hydrated. Hopefully, it won't be long until this unpleasant symptom eases and you may start to notice a difference by week 13 of pregnancy.


Headaches are another very normal symptom of pregnancy, caused by low blood sugar levels. Remember to keep snacking, drink plenty of water and ask your doctor for any pregnancy-safe painkillers should you need.

Breast tenderness

Hormones can cause your breasts to become sore, which often happens before you’re due your period as well. But good news! "Some women find relief from the symptoms experienced in the first trimester," says Ayanthi.

After week 12 breast tenderness should reduce as hormone levels start to become normal again.


You’re nearing the end of your first trimester, but your body may still be exhausted from growing your baby. That said, "you might experience an increase in energy levels as you enter the second trimester", says Ayanthi. If this isn't you, don't fret, just rest up when you can, and get ready for that energy burst that’s expected during trimester two!

Stomach cramps

Cramping is normal during early pregnancy, especially around week 12. A lot of women report feeling sharp pains on one or both sides of their groin as they stand up or twist. This is normal and is caused by the ligaments supporting your womb stretching as it grows.

12 weeks pregnant ultrasound

The 12 week scan is usually pretty exciting, as it will probably be the first time you see your baby. It typically lasts around 15 to 30 minutes, and the sonographer will listen for a heartbeat, check your baby's development and measure them for the first time - which will give everyone a better idea of how old your baby is, and work out your due date. Here's a look at a 12-week pregnancy scan so you can know what to expect.

12 week ultrasound

What to do at 12 weeks pregnant

Announce your pregnancy: If you haven't already, you may be considering sharing the news of your pregnancy with friends, family, and colleagues. Some parents choose to wait until after the first trimester due to a lower risk of miscarriage. There are lots of adorable announcement ideas to choose from.

Keep an eye on your health: Focus on continuing to maintain a healthy and balanced diet. Ensure you are getting essential nutrients, including folic acid, iron, and calcium. You should continue to take your pregnancy vitamins.

Gender guessing: At this time, it's usually too early to work out whether you're having a boy or a girl, so you'll have to wait until your 20-week scan to find out the gender of your baby. That said, some people believe in nub theory, which is where you determine the sex from the first ultrasound photo or there's even the Chinese gender predictor.

Start those pelvic floor exercisesPelvic floor exercises are so important (trust us!) Squeeze for up to 10 seconds, for 10 times and 10 quick squeezes, for 10 times. Not only can these muscles help during childbirth but they also reduce your chances of bladder issues and can help with postpartum symptoms. There are several pregnancy apps for fitness that you can download to help you.

Keep an eye out out: If you have painful cramps, bleeding or are feeling particularly lonely or sad, call the midwife or your doctor if you're having any concerns.

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.

About the expert

Consultant Obstetrician and Gynaecologist Ms Ayanthi Gunasekera is the Medical information lead at London Gynaecology

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