 [ Symptoms ] what can i expect during week 3 of my pregnancy [ Disease ] baby  congratulations if your egg and your partner is sperm have joined successfully your embryo is really there although it is very small    about the size of the head of a pin it does not look like a fetus or baby it is just a group of about 100 cells multiplying and growing rapidly the outer layer of cells will become the placenta and the inner layer will become the embryo mom to be  you will not notice any changes it is too soon remember you have not even missed your period yet tip for the week  home pregnancy tests are about as reliable as a urine test or blood test done in the doctor is office and can give you more immediate results than waiting for a doctor is visit to ensure accuracy make sure you have read the directions carefully and that all equipment being used is clean