You are 3 weeks exactly

A week after fertilization, the egg implants in your uterus, where it will soon develop into an embryo.

259 days until your due date

Around seven days after fertilization, the blastocyst implants in the uterus lining. Its outer layer, no longer protected, can now attach to the lining, which has become more receptive and "sticky" to help it hold on. The blastocyst breaks down cells in the lining to sink beneath the surface.

Its single outer layer of cells now becomes two. The outermost layer makes space by breaking down the lining and releases hormones that tell your body you're pregnant, so the uterus supports the pregnancy instead of shedding its lining in what would have been your period. The inner of these two layers will become the placenta and the amniotic sac around the embryo. Inside the blastocyst, an inner cell mass will form the embryo itself.

Good to know

Stretch and unwind

Relaxing can help while you wait to take a pregnancy test, and these simple stretches are a good way to fill the time and get in shape. Getting into the habit now will help your body cope with the extra demands of pregnancy. Stretch before and after exercise to prevent muscle strain.

Leg stretch: sit on the floor with your left leg out in front of you and hold your left foot with your left hand for a few seconds, feeling the stretch down the back of your leg. Don't worry if you can't reach your toes. Breathe in to begin and out as you stretch, then repeat with your right leg.

Back stretch: on all fours, lower your bottom toward your feet while stretching your arms out on the floor in front of you, hands flat. Lower your forehead as far as you can, keeping your neck and back aligned, and stretch your arms as far as possible. Breathe in slowly, then relax your back and arms as you breathe out. Repeat 10 times.

This is general information based on NHS guidance, not medical advice, and every pregnancy is different. Talk to your midwife or GP about anything that worries you. If your baby's movements slow down or change, or you have bleeding, severe pain or leaking fluid, call your maternity unit straight away. In an emergency, call 999.