Q: Last month my menstrual cycle was 28 days. This month it was 23 days. Is that considered a regular cycle or an irregular cycle and how do I calculate my ovulation day.
A: Your menstrual cycle lasts from the first day of your period until the day before your next period. If your menstrual cycle changes by more than two to three days, then it's considered irregular. So 28 days in one cycle and 23 days in the next is a five-day difference and the cycle is considered iregular. With irregular cycles, it's nearly impossible to accurately predict ovulation by calculating the days.