The first trimester – what is happening?

It still feels so unreal but also the least enjoyable trimester. Read more and find out why.

I always found it confusing that you could be 4 weeks pregnant when you have literally just found out about the pregnancy –  because the first 2 weeks technically don’t exist! It’s because the length of gestation is calculated from the first day of your last cycle, so your menstrual cycle is included in this.


Whilst it’s usually the least enjoyable of the trimesters, be it because of morning sickness, breast tenderness, extreme fatigue, cramping, or even just the stress of potential miscarriage, the first trimester is by far the most significant in terms of development and changes for both mother and baby.

Limbs and internal organs form

By the end of the first trimester the placenta is formed and is supporting the baby nutritionally, your baby’s limbs and internal organs are fully formed and the external sex organs are usually developed enough to determine the sex of the baby. By 12 weeks your baby will be about 4 inches long and weighing a little over an ounce. Your baby is moving a lot at this stage although it may be a while before you actually feel it! You may have started to gain weight too and your clothing may become tighter, it’s important to wear clothing that is comfortable.

Miscarriage risk reduced

For mom, reaching the end of the first trimester is a huge milestone. The risk of miscarriage is dramatically reduced, and you may have your first ultrasound, which makes everything feel so real! Many moms feel more confident telling people about their pregnancy once they have reached the 12 week mark, and if your symptoms have improved at the same time you may finally feel like you can actually enjoy being pregnant! – Kim Young

*Kim Young is a trained Hypnobirthing Childbirth Educator. View her website at here.



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