About the Menstrual Cycle Analyzer
A menstrual cycle is measured from the first day of one period to the first day of the next. According to WHO guidelines, a normal cycle is 21–35 days. Cycle-to-cycle variation of less than 7 days is considered regular. Irregular menstruation refers to cycles that fall outside this range or show large variation from one month to the next.
Common causes of irregular periods include stress, significant weight changes (either gain or loss), excessive exercise, thyroid disorders, polycystic ovary syndrome (PCOS), and hormonal imbalances. Irregularity is also normal in early adolescence and as women approach menopause. This tool uses 4 recent period start dates to automatically calculate cycle lengths and variation.
If results show irregularity, track for another 2–3 months to confirm the pattern. If periods are absent for 6 or more weeks, or if you experience severe pain or other unusual symptoms, consult a gynecologist promptly. This tool is not a substitute for medical diagnosis.
FAQ
Yes, minor variation is common even in healthy adults. Stress or sleep changes can shift a period by 2–3 days. Sustained variation of 7 or more days, however, warrants further investigation.
PCOS is one of the most common causes of irregular cycles. Hormonal imbalances disrupt ovulation, often leading to cycles longer than 35 days or periods that stop for months at a time. Diagnosis requires blood tests and an ultrasound.