Menstruation that comes last month 14, menses defer 4 days, morning makes water dipstick shows negat

The menstruation that comes last month 14 days and menstruation defer 4 days, show negative with morning uric dipstick, the likelihood that shows pregnancy is smaller. Most is because endocrine disorder is caused, defer 7 days belong to normal phenomenon, do not need to undertake treatment and processing. If defer days is longer, had better go to a hospital to undertake diagnose and treatment.