What happens in your second trimester

By the end of week 12 your baby would have grown from the size of a grain of rice to the size of a small orange! Find out what else you can expect from your baby’s development during the first 12 weeks

Week 4

Although you might have only just realised you’re pregnant, lots of amazing changes have already happened inside your body and your baby has taken the first important steps in its development. Despite only being the size of a tiny poppy seed, your baby’s nervous system and heart are beginning to form and blood has started to circulate around newly created blood vessels. Layers of cells have developed that will eventually become different parts of your baby’s body, including the brain, heart, lungs and intestines. That’s quite a lot in just four weeks, so it’s no wonder you might be feeling exhausted already.

Did you know? By four weeks your baby’s heart has usually started to beat, although it’s unlikely you’ll be able to hear it on a scan until later.

Weeks 5-8

Exciting developments will occur during these weeks with your baby’s face beginning to form, including spots where the nostrils and eyes will be and the ears beginning to emerge. Arms, legs, hands and feet are starting to develop, getting ready to start kicking in your second trimester, and your baby’s heart will have divided into two chambers beating at around 150 times a minute. Around your baby’s tiny body a delicate and translucent skin begins to form and the brain’s cells are well on their way to becoming an amazing command centre. Your womb will already have doubled in size to make space for your baby and you might find this means you need to go to the toilet more as it presses down on your bladder. You better get used to it though as it’s going to get a whole lot bigger before your baby is born.

Did you know? By eight weeks, your baby’s little fingers and toes will start developing.

Weeks 9-12

Your baby can now wave hello as its fingers and toes are clearly visible and can wiggle. Your baby will also start to swallow and kick now and, despite only being the size of a satsuma, all its major organs are fully developed. It’s also at this point that your baby’s reproductive glands are formed – the first outward sign if you’re having a boy or a girl – although they won’t be visible on a scan for a while yet, you can have fun guessing what you’re having. Taste buds are forming over the surface of your little one’s tiny tongue and their ears are almost fully developed – your baby is starting to look more like a person now with familiar features emerging, like the bridge of the nose and jawbone. Who will they look like?

Did you know? Your baby’s little fingers and toes can not only wiggle, but nails will begin to appear at their tips. Some babies are born with such long nails they’ll need a manicure straight away.