Periods, cycles, ovulation, and more: understanding the terms related to menstrual health is one way you can empower yourself to make informed decisions about your healthcare and wellbeing. It can also make discussions with your healthcare provider easier. Plus, knowing more about your body is never a bad thing— understanding what’s normal (especially when it comes to reproductive health) can help you notice when something is wrong, so you can receive care sooner.
Key Terms and Definitions
- Menstruation/Period: Monthly shedding of the uterine lining, usually lasting between 2 and 7 days. This is the portion of your cycle where you experience bleeding.
- Menstrual cycle: Time from the first day of one period to the first day of the next; the average cycle is 28 days, but anywhere between 21 and 35 days is normal.
- Ovulation: Release of an egg from the ovary, usually during the middle of the cycle. This is when you are at your most fertile.
- Premenstrual Syndrome (PMS): Physical and emotional symptoms (tender breasts, mood swings, bloating, cravings, etc.) occurring before menstruation.
Cycle Patterns
- Regular Cycle: Consistent menstrual cycle timing, around 21-35 days apart.
- Irregular Cycle: Varying menstrual cycle length or missed periods; irregular cycles may indicate other underlying health issues.
- Amenorrhea: Absence of periods.
- Primary amenorrhea: Menstruation has not started by age 15.
- Secondary amenorrhea: When someone who previously had periods does not have a period for more than three to six months.
- Oligomenorrhea: Infrequent menstruation (less than six to eight periods in a year).
When to Seek Medical Advice
Periods lasting more than 8 days, occurring less than 21 or more than 35 days apart are a sign to reach out to a healthcare provider. You should also seek medical advice if your cycle timing suddenly changes. Severe PMS or pain during your cycle that interferes with daily life are other symptoms that shouldn’t be ignored.
Conclusion
Understanding menstrual health can feel daunting, but you’ve already taken the first step toward education and awareness! If you’d like to learn more, Ovia has dozens of articles on menstrual health. Click here to navigate to articles. Tracking your cycle is another great way to stay on top of your health, and it can make it a lot easier to notice when your cycle has changed. If anything seems out of the ordinary, though, consult your healthcare provider.
Reviewed by the Ovia Health Clinical Team
Sources
- “Your First Period.” ACOG, June 2022, www.acog.org/womens-health/faqs/your-first-period.
- “The Menstrual Cycle: Office on Women’s Health.” OASH | Office on Women’s Health, womenshealth.gov/pregnancy/menstrual-cycle. Accessed 8 Dec. 2025.
- Pinkerton, JoAnn V. “Premenstrual Syndrome (PMS) – Gynecology and Obstetrics.” MSD Manual Professional Edition, Aug. 2025, www.msdmanuals.com/professional/gynecology-and-obstetrics/abnormal-uterine-bleeding/premenstrual-syndrome-pms#Diagnosis_v1062702.
- Welt, Corrine K. “Normal Menstrual Cycle.” UpToDate, Nov. 2025, www.uptodate.com/contents/normal-menstrual-cycle.
- Welt, Corrine K. “Absent or Irregular Periods.” UpToDate, Nov. 2025, www.uptodate.com/contents/absent-or-irregular-periods-beyond-the-basics. “Menstrual Cycle.” Office on Women’s Health, Feb. 2021, womenshealth.gov/menstrual-cycle.
