Your baby grows and develops quickly in the first trimester. By the time you are 10 weeks pregnant (eight weeks after fertilisation) all the body parts are present, if not quite fully developed, and the placenta is fully formed. At this point, the embryo is known as a foetus. Nutrients are transferred from you to the baby through the placenta. Waste products from the baby are returned to your circulation to be removed.
By the time you are 12 weeks pregnant (10 weeks after fertilisation) your baby is approximately 60mm long. At this stage, your baby’s forehead grows with the developing brain, the eyelids are still sealed shut and the ears are forming.