Your baby is the size of a passion fruit

12 Weeks Pregnant: Your Baby’s Development

At 12 weeks pregnant, you’ve nearly reached the end of the first trimester, and your little one has been just as busy as you!

All of the foetus’s vital organs and body parts are in place, including the organs, muscles, limbs and bones. Although the foetus is now fully formed, there’s lots of growing and maturing that still needs to take place. And that’s just what will take place between now and when you give birth.

Although the sex organs have developed, it’s still too early to determine the gender of the foetus during an ultrasound. Your doctor may be able to reveal whether you’re having a boy or girl (if you choose to find out) during a mid-pregnancy ultrasound scan, which takes place in a few months. In the meantime, enjoy finding both boy and girl names using our Baby Name Generator.

By now, the foetus is moving around a fair bit, but it’s still too early for you to feel these movements.

Now that you’re 12 weeks pregnant, the foetal heartbeat is likely audible during an ultrasound scan, so you may get the opportunity to hear it if you have a check-up scheduled for this week.

The Size of the Foetus at 12 Weeks Pregnant

At 12 weeks, the foetus is now about the size of a passion fruit, measuring close to 5.5 cm, crown to rump, and weighing approximately 18 grams.

Take a look at the illustration below to get a visual idea of how your baby is developing:

Foetus at 12 weeks pregnant

Mum’s Body at 12 Weeks Pregnant

Feed me! As the nausea and discomfort of early pregnancy start to subside, you may find that you're getting your appetite back. Be sure you're eating enough and maintaining a healthy diet, but don't feel you actually need to eat for two.

Experts recommend adding only about 200 extra calories a day, on average, during pregnancy. By the way, that's only two slices of wholemeal toast!

Most mums-to-be will put on 10 to 12 kilograms during pregnancy, but most of this will be gained after week 20.

Focus on sticking to a balanced pregnancy diet that includes proteins like chicken, eggs, fish, or plant-based substitutes like beans. Include a wide variety of vegetables and fruits to ensure you get plenty of vitamins and minerals. Carbohydrates are also important as they can give you extra energy and increase your fibre intake. Just try to choose wholegrain or higher fibre options like brown rice, and potatoes with the skin on.

Don't stress about adding all food groups to each and every meal, instead aim for a balanced diet over the course of each week.

While we're on the topic of food, there are some foods you should avoid entirely while pregnant. These include some types of fish, and undercooked meat and eggs, among others. Read more about what not to eat when pregnant.

12 Weeks Pregnant: Your Symptoms

Here are some of the symptoms you may be experiencing at 12 weeks pregnant:

  • Constipation. Although this symptom is quite common during pregnancy, knowing this doesn't make it any easier to deal with the discomfort of feeling blocked up. Ease this symptom by eating more fibre and drinking lots of water.

  • Bleeding and sensitive gums. Hormonal changes can cause plaque build-up leading to swollen, bleeding and sore gums. Although this can be disconcerting, it can be completely normal. Continue to brush and floss regularly and avoid sugary drinks and snacks. During pregnancy you may be eligible for free dental care, ask your dentist about this when booking you regular check-up.

  • Oily and spotty skin. Ask your GP if they have any recommendation for dealing with this annoying symptom based on your skin type.

  • Stomach pain. Getting and achy stomach or cramping at 12 weeks pregnant is usually nothing to worry about. This symptom may be caused by constipation, wind, or the feeling of your muscles and ligaments stretching as your uterus grows. If the pain is severe or accompanied by other symptoms like bleeding, see your midwife for a check-up.

  • Feeling dizzy. Feeling lightheaded during pregnancy can be normal, but if the feeling persists, ask your midwife for advice.

  • Sensitivity to smells. If certain odours bother you, try to avoid them until this symptom passes.

  • Bloating. Wondering whether it's a bump or bloat? Yes, we know, it's annoying that hormonal changes can leave you feeling bloated at 12 weeks pregnant. Eating slowly and eating six small meals a day instead of three big ones might help. And, don't worry. In time it will be perfectly clear that it's a gorgeous bump!

  • Light spotting. At 12 weeks pregnant, you might see the occasional drop of blood, but if you notice heavier bleeding, head to your doctor right away.

12 Weeks Pregnant: Things to Consider

  • You might be looking at your belly and wondering if it's the right size for 12 weeks pregnant. Try not to compare your bump to other mums-to-be. Every pregnancy is unique and it will depend on many factors like your build, whether you're pregnant with twins, your pre-pregnancy weight, and whether this is your first baby.

  • The flu jab will protect you and your foetus, and is safe. It's also free for mums-to-be in the UK. The flu vaccine is available from September until about February, and you can get the vaccine no matter how far along you are. Aim to get it as soon as possible.

  • Kegel exercises help strengthen the pelvic floor muscles that support your uterus and bladder. There are many benefits, including helping to prevent accidental urination during and after your pregnancy. Kegels are easy to do: Simply squeeze your pelvic floor muscles by contracting those muscles you'd clench if you were trying to stop the flow of urine or stop yourself from passing wind. Hold each squeeze for a few seconds, and then release. Do about 10 to 15 of them 3 times a day. Or clench and hold for 10 seconds a time. If you're unsure that you're doing Kegels right, your midwife will be able to help.

  • You might want to write down all of your exciting pregnancy milestones so that you can look back on your journey after your baby is born. Consider taking weekly pictures of your growing bump after it begins to show. When you have an ultrasound scan, you may get a picture, which you can also add to the journal. You can buy pregnancy journals online or from a newsagent or gift shop, or you can create your own in the form of a scrapbook or notebook.

  • Although your doctor and midwife are the best source of personalised guidance, you may like to check out our Pregnancy Weight Gain Calculator. It can give you a rough idea of what healthy pregnancy weight gain looks like for someone of your pre-pregnancy weight.

  • As you enter the second trimester you may be thinking of telling your colleagues about your pregnancy. It can be hard to decide on the best way to approach it, so we’ve collected some fun ideas on how you can announce your pregnancy to co-workers with ease.

  • You won’t be able to find out your baby’s gender for several weeks yet, that’s if you even want to know before your baby’s birth! But that doesn’t mean you can’t have some fun with our What’s Your Baby’s Gender? quiz. Time will tell if the quiz results were spot on, or not quite right. It’s all in good fun!

12 Weeks Pregnant: Ask Your Doctor

  • What screening tests will you be offered in the coming weeks, and are they recommended for your situation?

  • Where should you go to get the flu jab?

  • What are your options for where to give birth, and what is the doctor's expert recommendation?

  • When is it OK to share the news of your pregnancy with friends and colleagues?

  • Is travel safe during the second trimester, what about flying?

  • What is the right amount of pregnancy weight gain for your situation, and are you on the right track at 12 weeks pregnant?

12 Weeks Pregnant: Your Checklist

  • Read about how to claim maternity leave and start to plan when you will tell your employer about your pregnancy.

  • If you haven’t already shared the news, think about how you will reveal your big news to family and friends. You could organise a fun pregnancy announcement party, or you could give those closest to you a special pregnancy announcement card. No matter how you do it, your loved ones will cherish this special moment.

  • Schedule a dental check-up. Remember, you may be entitled to free dental care!

  • Research local antenatal or birthing classes — your midwife will be able to point you in the right direction. Find out when they start and when you need to sign up. It might seem like it’s too early, but these classes can fill up.

  • Sign up for even more weekly pregnancy tips:

How we wrote this article
The information in this article is based on the expert advice found in trusted medical and government sources, such as the National Health Service (NHS). The content on this page should not replace professional medical advice. Always consult medical professionals for full diagnosis and treatment.