Most of the changes taking place in your body won't be obviously noticeable: your body will now be producing more blood as the placenta uses aroud 25% of the blood in your body, your cervical mucous will form a plug at the opening of your cervix to protect your baby from the outside world. This plug will stay in place until your cervix begins to dilate ready for delivery, either late in your pregnancy or during your labour.
However invisible, these changes are taking a toll on your body and you are probably still feeling incredibly tired. Get your partner to help out around the house where possible and forget about all but the basic chores.
Sadly, around 25% of pregnancies will end in miscarriage, most commonly between 6-8 weeks. Signs to watch for include vaginal bleeding and cramping similar to period pains. Many women who experience vaginal bleeding in early pregnancy go on to have a healthy baby, but if you have any bleeding at all it's important to let your GP or LMC know immediately.
Your baby now measures about 5-13mm in length from top to bottom and weighs about 0.8 grams.
At this stage your baby has a shape similar to a sea horse, his or her head is much bigger in proportion to the rest of the body.
Your baby's heart is now beating at a rapid 150 beats per minute (almost twice an adults heart rate) and has divided into right and left chambers. Other areas that are developing include your baby's digestive system, lungs, pituitary glands and muscle fibres.
Your baby's arms and legs are now starting to resembles paddles while fingers and toes are forming. Baby's jaw, mouth, lips and tongue are continuing to develop and grow and are also now visible.
Although you won't be able to feel them for several weeks, your baby is also beginning to make tiny movements.
If you have had fertility treatment, are unsure of your dates or have a history of miscarriage you may have an ultrasound this week to check on your baby's progress. This scan will confirm your due date and whether you are carrying one or two (or more!) babies, and you should also see your baby's heartbeat, a reassuring sign!