When the sperm meets the egg in the abdomen of the fallopian tube, a fertilized egg is formed. It takes about 6-7 days for the fertilized egg to reach the endometrium from the abdomen of the fallopian tube and to implant. After the fertilized egg has implanted, sensitive women may feel a slight drop in body temperature, a vague pain or soreness in the lower abdomen, and swelling and nipple tenderness in the breast area. After the fertilized egg is laid in the endometrium, the trophoblast cells secrete chorionic gonadotropin, and pregnant women may experience nausea, vomiting, and aversion to grease due to hormone levels. Pregnancy can be ruled out by a blood test for chorionic gonadotropin as early as the 8th day after intercourse in women of childbearing age.