What is the reason for delaying menstruation for 4 days?

If a woman's menstrual cycle is normal, the symptoms of menstrual delay suddenly appear. Generally, the results of pregnancy test are inaccurate after delaying 4 days. At least 7 days later, the results will be more accurate. It is recommended to continue observation. If the menstrual delay exceeds 7 days. Or go directly to the hospital for examination.