Understanding Your Menstrual Cycle
A typical menstrual cycle lasts 21-35 days, with 28 days being average. Day 1 is the first day of your period. Cycle length is measured from the first day of one period to the first day of the next.
Cycle Phases
- Menstruation (Days 1-5): The uterine lining sheds. Period bleeding typically lasts 3-7 days
- Follicular phase (Days 1-13): Estrogen rises. Follicles develop in the ovary, one becoming dominant
- Ovulation (~Day 14): The mature egg is released from the ovary. This timing shifts based on your cycle length
- Luteal phase (Days 15-28): Progesterone rises. The uterine lining thickens in preparation for possible pregnancy. This phase is consistently about 14 days regardless of cycle length
Predicting Ovulation
Ovulation typically occurs 14 days before your next period starts (not 14 days after your last one). For a 28-day cycle, that's day 14. For a 32-day cycle, it's around day 18. For a 24-day cycle, day 10.
Fertile Window
You're most likely to conceive during the 6 days ending on ovulation day:
- Sperm can survive up to 5 days in the reproductive tract
- The egg lives only 12-24 hours after ovulation
- Peak fertility: the 2 days before ovulation, not the day itself
Cycle Variation Is Normal
It's normal for cycle length to vary by a few days month to month. Factors that can temporarily affect your cycle:
- Stress: Can delay ovulation, making cycles longer
- Exercise: Very intense training can shorten or skip periods
- Weight changes: Significant gain or loss affects hormones
- Travel and sleep: Disrupted circadian rhythm can shift timing
- Illness: Being sick near ovulation can delay it
When to Consult a Doctor
- Cycles consistently shorter than 21 days or longer than 35 days
- Very heavy bleeding (soaking through a pad/tampon every hour)
- Severe pain that disrupts daily activities
- Missed periods for 3+ months (not pregnant)
- Sudden change from previously regular cycles
- Bleeding between periods or after intercourse