There are many reasons why menstruation is delayed for 4 days with vaginal bleeding, it may be the impending onset of menstruation, or it may be the result of bleeding from the implantation of pregnancy, miscarriage with precursor, ectopic pregnancy and so on. 1. The onset of menstruation: due to emotional instability, tension, anxiety, fatigue and other factors can affect the time of menstruation, menstruation delayed for no more than 1 week is generally a normal phenomenon, menstruation delayed for 4 days with vaginal bleeding may be the onset of menstruation, you can continue to observe. 2. Pregnancy implantation bleeding: 2 to 3 weeks after ovulation, the fertilized egg will implant in the uterine lining and stimulate the uterine lining, resulting in the rupture of small blood vessels and a small amount of bleeding, as the delay of menstruation for 4 days happens to be in this time period, so the delay of menstruation for 4 days with vaginal bleeding may be caused by pregnancy implantation bleeding. 3. Pre-eclampsia: poor embryonic development or low progesterone, resulting in a small amount of bleeding, menstruation delayed 4 days a little light bleeding, accompanied by abdominal pain and other uncomfortable symptoms. 4. Ectopic pregnancy: the fertilized egg is deposited in a part of the uterine cavity other than the uterine cavity, and the level of human chorionic gonadotropin is lower than that of a normal pregnancy, which causes vaginal bleeding, and there is a delay in menstruation for 4 days with vaginal bleeding, accompanied by abdominal pain and other uncomfortable symptoms. There are other possibilities for delayed menstruation with vaginal bleeding for 4 days, you should go to the hospital in time, clarify the cause of the disease, under the guidance of a professional physician, and follow the doctor’s instructions for treatment, do not self-medication, so as not to delay the condition.