A pregnant for the first time woman will notice the amazing fatigue and hypersensitivity of the breast. There is a delay in menstruation to 7 days. Pregnancy tests of morning urine may show a second strip or may not, so the most reliable method of determining pregnancy rate is the human chorionic gonadotropin (hCG) in the blood. During this period, on the back of the embryo a groove is formed, which will become neural tube. The neural tube becomes the chord, spinal cord and nervous system consequentially. By the end of the week on both sides of the neural tube are formed segments – prototypes of muscles and bones. Begins the formation of the cardiovascular system. First of all the vials appear from the mesodermal cells – in the embryo in the yolk sac and the corpus luteum. A primitive heart – a tube, is formed on the chest. The size of a child is about 10 mm, as the lowercase letter “o” in the printed text of the book. It is recommended to take iodine (if needed), and folic acid. Upon the occurrence of pregnancy a woman continues to receive maintenance therapy with progesterone. If reproductologist appointed injectable form, administered oil solution can provoke the appearance of infiltrates.