Does delayed menstruation means that i had a miscarriage and i am not aware of it, as i am having fluctuations in the cycle since past one year.

Not necessarily: Delayed menstruation may occur with an early miscarriage where pregnancy has not been diagnosed. The menstrual period may be heavier and more uncomfortable if this is the case. This probably happens more often than we realize since human pregnancy overall carries approximately 50% miscarriage rate. Once clinically evident, that rate drops to 15-20%.