Congratulations! You are now in your 12 weeks pregnant, and have made it through your first trimester.

Your clothes might be feeling a little tight at this stage, and you’ve probably had enough of all the frequent bathroom trips.

For many pregnant women, the first trimester can feel a bit of a drag with not a lot to show for it. However, you might be surprised to learn just how much is happening inside your baby’s world right now.

Let’s take a peek.

How many months is 12 weeks pregnant?

12 weeks pregnant means you are now 3 months into your pregnancy. It might have flown, or it might have felt a bit of a challenge. Everyone will feel differently at this stage.

Generally, moving into the second trimester is an exciting phase of your pregnancy.

12 week fetal developmental stages

In western medicine, your pregnancy is actually calculated from the first day of your last menstrual period, also known as your LMP.

Use our Due Date Calculator to calculate your dates.

Depending on your cycle, this means that conception (the joining of the sperm and the egg) will take place roughly 2 weeks after your last period. This is also known as fertilization.

Within 24 hours of fertilization, the egg begins to divide rapidly into many cells.

At this stage, the collection of cells is known as a blastocyte.

The inner cells within this mass, will subsequently form the embryo.

A pregnancy is considered ‘successful’ once the embryo has embedded into the lining of the uterus. This happens about 6-10 days after fertilization, and is known as implantation.

As this happens you might experience some Implantation Bleeding.

When does an embryo become a fetus?

Typically the embryonic stage begins at fertilization and continues for 8 weeks.

Remember that pregnancy is counted from your last period (2 weeks before you conceive).

This means that 8 weeks after fertilization is actually 10 weeks of pregnancy (yes, it’s a bit confusing)

From 10 weeks of pregnancy, your baby has now graduated from embryo to fetus and has entered the fetal stage of development.

Should I be showing at 12 weeks?

Although your waistline might have expanded a little, and you probably prefer joggers over jeans at this point, you’re unlikely to look noticeably pregnant at 12 weeks.

You might have a small baby bump that you and your partner are able to see, but those who aren’t expecting it or who aren’t looking closely enough won’t be able to tell you’re pregnant at this stage.

This is mainly because, at pregnancy week 12, the uterus is about the size of a grapefruit but remains contained within the pelvis.

It’s not until the second trimester, when the womb rises up into the abdomen, that your baby bump will become more obvious, and you’ll start to show.

Everyone’s bump will look different, because everyone’s body is different. Try not to compare yourself with others. Many women won’t look pregnant at all at 12 weeks, but for some it will be more obvious.

There are several factors that influence how you carry your pregnancy, and how much you show. All bumps will vary, depending on your pre pregnancy weight and build, your hormones, how many babies you’ve had before, and even your muscle tone.

Don’t panic if your bump looks bigger or smaller than another mom’s – even if you are the same number of weeks pregnant.

12 week fetus ultrasound

At this stage you might have seen your doctor for your first prenatal checkup and discussed having an ultrasound and various screening tests.

If you have decided to have an ultrasound, usually between 11 and 13 weeks, you’ll be able to see just how much your baby is growing.

What can I expect at my 12 week ultrasound?

Due to the size of your baby, what you’ll see is limited, compared with a scan later on in pregnancy.

There are 4 main aims of a first trimester ultrasound:

Dating

If you’re unclear on your dates, or if you had irregular periods, or had been on some form of hormonal contraception prior to getting pregnant, sometimes if can be difficult to calculate your pregnancy accurately.

If you’re unsure about when you conceived, you might have a first trimester ultrasound at this stage. It is sometimes referred to as a pregnancy dating scan. It will give you an accurate estimated due date (EDD), and will calculate exactly how many weeks and days pregnant you are. Some women find they are further along, or less far along, than they expected.

How many babies?

For most women this will be the first scan in the pregnancy, and the first opportunity to see whether there’s more than one baby growing inside.

Twins can be detected on ultrasound as early as 6 weeks, but the best time to have an ultrasound is around 10-12 weeks.

At this stage it’s clear to see what type of twins you’re carrying, as your health professional will be able to see how many fetuses, placentas, and amniotic sacs are present.

If you became pregnant following fertility treatment, or had any early signs of problems or complications, such as bleeding in the pregnancy, you might have already had an earlier scan. If so, you might already be aware you’re having twins.

Location

An important part of the scan is to ensure your baby is growing in the right place. By now your baby should have found it’s home, embedded into the lining of the womb.

In about 1% of pregnancies, the embryo develops outside of the uterus. An embryo cannot survive outside the uterus as it doesn’t have the right conditions to grow; it can also be very dangerous for the mother.

This is known as an Ectopic Pregnancy, which usually occurs when the embryo becomes stuck, and develops inside the fallopian tube, instead of the uterus. It is a serious complication, and usually involves surgery to remove the pregnancy.

Baby’s development

At your scan your doctor will be able to check on your baby’s health and development to make sure your little one is growing the way that she should.

Screening at 12 weeks pregnant

You might have chosen to have genetic screening tests in addition to your ultrasound scan.

This screening assesses the risk of various chromosomal abnormalities, such as Down’s Syndrome and other birth defects.

If you’ve opted for this, an additional measurement will be performed on the scan. This is known as the nuchal fold, or nuchal translucency (NT) measurement.

The World Health Organisation new model recommends pregnant women to have their first medical contact during the first 12 weeks’ gestation, with following medical contacts taking place at 20, 26, 30, 34, 36, 38 and 40 weeks’ gestation.

You might be asked to attend your scan with a full bladder, which will push your baby higher into the pelvis. This makes it easier for the sonographer to take measurements accurately.

Can you tell gender at 12 weeks?

If you’re looking to find out the gender of your baby, you might have to wait a little bit longer.

Your baby’s sex will have already been determined at conception, and the sex organs will have already formed; however, they are not clearly visible on ultrasound at this stage.

Most expectant parents will find out the sex of their baby at their mid trimester scan (anatomy scan). This is normally performed between 18 and 20 weeks.

Is a fetus fully formed at 12 weeks?

At 12 weeks pregnant, your baby is now fully developed. All the body parts, internal organs, muscles, and bones are already in place, and body systems are also fully formed.

With everything in place, there’s still a lot of maturing and growing that needs to happen as your pregnancy progresses.

Although she might be small, you’ll be surprised to see on the ultrasound how your little one actually moves and wriggles quite a lot.

It’s crazy to think that your baby’s heart will have started beating around 5-6 weeks.

If you’ve already had an appointment with your midwife or doctor, they might or might not have been able to detect it. This is completely normal either way.

At 12 weeks it’s sometimes still too early to hear your baby’s heartbeat with a hand held doppler device.

The successful of this will depend a lot on where your baby happens to be lying at that moment, rather than the health of your baby.

You’ll be able to see the heartbeat on the ultrasound, though; what a wonderful feeling!

What does a fetus look like at 12 weeks?

You have probably been wondering what your baby will look like at 12 Weeks Pregnant.

The arms and legs are now more in proportion to the rest of the body, and there will be little tiny fingers and toes formed.

Your baby’s head will still look a little large in comparison with the rest of the body, but this will soon even out as your baby grows.

The umbilical cord will be present but it will be quite short still. This is what’s keeping your baby attached to the placenta so she can receive everything she needs grow and thrive in the womb.

If you have chosen to have an ultrasound, you might even be able to see primitive breathing movements as your baby begins to practice using her lungs.

How big is a 12 week fetus?

At pregnancy week 12 your baby is close to 5.5cm in length from crown to rump, and roughly the size of a lime.

By now your baby will weigh around 15-18 grams – about the weight of 3 grapes – and will have doubled in weight since last week.

Is 12 weeks pregnant the safe zone?

Many women wait until after their first ultrasound, or they reach the 12 week mark before announcing their pregnancy to the world.

There are many reasons why 12 weeks of pregnancy is seen as a milestone.

It’s thought that around 80% of miscarriages occur in the first 12 weeks.

After this point, the risk of miscarriage is significantly reduced. Now that your baby is fully formed the placenta has now taken over from the yolk sac in feeding your baby.

This means your pregnancy hormones are now more settled, and you’re probably starting to feel a little brighter, with a little more energy.

What should I be feeling at 12 weeks pregnant?

You’ll be pleased to know that many of the early pregnancy symptoms such as morning sickness, feeling dizzy, and the constant need to pee should have disappeared by now.

If you ‘re still experiencing some of them, it’s totally normal. But don’t worry, you’re heading in the right direction. Your first ultrasound scan can feel like a turning point which makes it feel all worth while.

Your growing uterus will still be tucked behind your pubic bone at this point. You might be feeling a little a bit thicker around the waist but you won’t be showing just yet.

This stage can be hard for some women as they want to feel excited about their pregnancy, but physically might not be feeling great.

It’s still too early to be feeling your little one move just yet, but that doesn’t mean she isn’t kicking away inside. It’ll be a few more weeks before you start feeling the first little flutters.

If you haven’t already seen your healthcare provider for your first prenatal check up, now is the time. Book your antenatal appointments as soon as you can.

If you haven’t yet decided, read How Do I Choose A Care Provider? for more information.

Although the birth might seem a long way away at this stage, now is a great time to start thinking about your birth plans and antenatal classes. Think about where you would like to give birth to your baby – whether in a hospital, a birth center, or at home.

If you’re not sure, or wondering what the best option would be for you and your family, ask your midwife at your next appointment.