By the time you are six to seven weeks pregnant, there is a large bulge where the heart is and a bump at the head end of the neural tube. This bump will become the brain and head. The embryo is curved and has a tail – it looks a bit like a small tadpole.
The heart can sometimes be seen beating on a vaginal ultrasound scan at this stage.
The developing arms and legs become visible as small swellings (limb buds). Little dimples on the side of the head will become the ears, and there are thickenings where the eyes will be. By now the embryo is covered with a thin layer of see-through skin.
Conception usually takes place about two weeks after your last period, around the time that you ovulate (release an egg). In the first four weeks of pregnancy you probably won’t notice any symptoms. The first thing most women notice is that their period doesn't arrive. Find out about the signs and symptoms of pregnancy.
By the time you are eight weeks pregnant, you will probably have missed your second period. However, some women experience a little bleeding during the early weeks of pregnancy. Always mention any bleeding in pregnancy to your midwife or GP, particularly if it continues and you get stomach pain.
Your womb has grown to the size of a lemon by the time you are around seven or eight weeks pregnant. You're probably feeling tired. Your breasts might feel sore and enlarged, and you are probably needing to pass urine more often than usual.
Some pregnant women start to feel sick or tired, or have other minor physical problems for a few weeks around this time. Most women stop having morning sickness and start to feel better by the time they are around 14 weeks pregnant.