13 weeks pregnant: your baby’s development and changes in your body

At 13 weeks pregnant, you’re at the start of your second trimester, and, whilst it might be hard to believe, you’re already a third of the way through your pregnancy!

A lot of mums-to-be find that some of those pesky early pregnancy symptoms start to ease in the second trimester, and they get a lot of their energy back¹.

Meanwhile, there’s plenty going on for your baby, too. They’re growing and developing quickly and even starting to wriggle around in your womb².

At 13 weeks pregnant, scans and second-trimester symptoms are likely on your mind. Let’s take a look at everything you need to know.

Converting 13 weeks pregnant to months can help you get a better idea of how far along you are. 13 weeks is just over 3 months, which means you’re right at the start of your second trimester.

Although there’s no specific 13 weeks pregnant ultrasound, by now, you might have had your first pregnancy scan and started to share your exciting news with family and friends - which can make it all feel even more real!

At 13 weeks pregnant, your baby is very active, spending lots of time stretching, kicking and turning (although they’re still far too small for you to feel it)².

Some babies start to suck their thumb in the womb, which helps them practice the sucking reflex they’ll use to feed once they’re born².

Their organs are developing all the time too, including their ovaries or testes and their digestive system³.

At 13 weeks pregnant, your baby’s size is about 7.4cm, or around the size of a peach². As the weeks go on and their body develops, they look less and less like a tadpole and more and more like the baby you’ll meet in around 6 months.

Your first pregnancy scan is often called your dating scan or the 12-week scan, but it can happen any time from 10 to 14 weeks pregnant⁴. At 13 weeks pregnant, the ultrasound can show your baby’s size (which can give you a more accurate due date), their position, and whether you’re expecting more than one baby⁵.

It’s not just your baby whose body is changing at 13 weeks pregnant, there are lots of changes happening in your body too.

Every pregnancy is different, and some expectant mums won’t notice a bump until later in their pregnancy. But it’s possible that your 13 weeks pregnant belly will start to show signs of a small baby bump, especially if this isn’t your first pregnancy².

During pregnancy, your body pumps a lot more blood around your pelvis, which can increase your sex drive. There’s no reason why you can’t have sex while pregnant, unless your doctor or midwife has advised you not to².

You’re more likely to experience painful, swollen or bleeding gums during pregnancy. It’s important to keep up with your normal dental hygiene routine (including brushing twice a day) to help avoid gum disease. You can also switch to a soft-bristled toothbrush to make brushing more comfortable².

In your second trimester, you’ll likely find that some of your early pregnancy symptoms improve. But some, like constipation and cravings, might still be hanging around. You may also find that some new ones come along to join them, too.

Let’s take a look at some of the 13 weeks pregnant symptoms you might experience as your second trimester gets underway.

It’s common to feel constipated or bloated during pregnancy due to   your changing hormones.

Things you can do to help prevent constipation include⁶:

• Getting lots of fibre in your diet by eating fruit and veg, pulses, and wholemeal carbs (like brown bread)
• Drinking plenty of water
• Exercising regularly

Constipation and bloating can be painful, but the discomfort usually goes away after a little while, especially if you switch positions or go to the toilet. If you’re 13 weeks pregnant and cramping severely or for a long time, get in touch with your maternity unit⁷.

Your pregnancy hormones can also make your breasts feel tender, sore, or even tingly. Your breasts will continue to change throughout your pregnancy, and you might notice that⁸:

• Your nipples become darker
• You get stretch marks or noticeable veins on your breasts
• Your breasts start to produce milk (usually from around 16 weeks pregnant)
• Your nipples and breasts become larger, especially in the last few weeks of pregnancy

We’ve all heard about strange and wonderful pregnancy cravings - pickles and ice cream anyone?

During pregnancy, some, but not all, women notice changes in their sense of taste and smell during pregnancy, which make them crave foods they’re not usually interested in. If you’re having cravings, try to stick to a healthy, balanced diet  (even if all you want to eat is quite the opposite)⁹.

If you start to crave things that aren’t food, like dirt or clay, it could be a sign of a condition called pica, which is caused by low iron. Speak to your doctor or midwife about your symptoms to get support⁹.

At 13 weeks pregnant, you might want to think about²:

• Letting your work know that you’re pregnant. Your maternity rights mean that you can go to antenatal appointments on paid work time. You might also want to ask for a risk assessment to make sure your environment is safe for you and your baby. 
• Doing pelvic floor exercises. Strengthening your pelvic floor muscles during pregnancy can help prepare your body for labour and beyond.
• Eating a healthy, balanced diet. ‘Eating for two’ during pregnancy is actually a myth! You won’t actually need any extra calories until your third trimester. Just try to eat a variety of different foods every day, including plenty of fruit and veg.

During this stage of pregnancy, breasts can start to feel a bit lumpy – but don’t worry, it’s just that your mammary glands and ducts are developing in time for the birth. Your breasts may soon start making a thin yellow liquid called colostrum. This is packed with nutrients and will be the first milk that nourishes your baby after the birth before their regular milk starts to flow.

The good news is that size doesn’t matter so even if your breasts are small, you should still be able to breastfeed if you want to!