The first trimester of pregnancy

Your first trimester lasts 12 weeks in total, and starts from the first day of your last period. This means that by the time you’ve taken a pregnancy test and had a positive result, you could already be five or six weeks pregnant.

All of the hormonal changes your body goes through during the first trimester can affect your digestive system, and unfortunately diarrhoea can be a common side effect. It’s all part and parcel of pregnancy so try not to worry. It’s a good idea to drink plenty of water if you can until the symptoms pass, because diarrhoea can leave you dehydrated. And of course, if you have any questions or concerns, speak to a pharmacist or your GP.

Light bleeding, spotting and cramps are very common during early pregnancy and are usually no cause for alarm. However, if you experience any heavy bleeding, or cramps that feel stronger than period pains, it’s best to give your GP a call, just to be on the safe side.

While some women so no sign of extra weight for months, others put on weight from the get-go. Whichever camp you fall into, try not to stress about it. The reality is that every woman puts on extra weight during pregnancy – you can thank all the extra litres of bodily fluids, the increasing size of your uterus and breasts and the small human you’re growing for that!

Pregnancy weight gain is different for everybody – and for every pregnancy for that matter. We’ve got lots of information to help you understand a bit more about weight gain in pregnancy and what to expect.

Flying during your first trimester is totally up to you. While it’s perfectly safe to fly during the first three months (and beyond!), if you’re feeling nauseous and sick or tired and low on energy, you might prefer to give travelling a miss.

Last reviewed: 31st August 2020
Reviewed by Nutricia’s Medical and Scientific Affairs Team