Understanding what’s normal and what’s not when it comes to menstrual health may be one of the best things you can do for yourself. Tracking your cycle and understanding your normal can help you make informed decisions when it comes to your care. When something changes or seems off, you’ll know. Early intervention is the key to treating symptoms as soon as they appear and uncovering underlying issues. Before reading on, be sure to read this article, which details the definitions of some common terms surrounding menstrual health.
Normal Period Parameters
According to the American College of Obstetricians and Gynecologists (ACOG), these are the normal features of a healthy menstrual cycle:
- Cycle Length: 21–35 days
- Bleeding Duration: 2–7 days
- Color: Fresh blood is bright red and older blood is dark red/brown— both of these are normal. You may also notice a pink color at the beginning or end of your period when small amounts of blood mix with vaginal discharge.
- Clots: Small clots (less than one inch) are normal and common during heavy flow days.
Average menstrual flow is usually around 35-60 mL, which is 2 ounces or less, but it can vary a lot from person to person. Especially on heavy flow days, it may seem like periods can cause a lot of blood loss. But normally, menstrual fluid is less than half blood. The rest of the menstrual flow is endometrial tissue from the lining of the uterus, as well as mucus and vaginal or cervical discharge. If you’re concerned about how much bleeding you have during periods, the total amount can be guessed using
Pictorial Blood Loss Assessment Chart (PBAC): A validated tool that helps estimate blood loss based on the number and saturation level of pads/tampons, presence of clots, and flooding episodes. A PBAC score >100 may indicate heavy menstrual bleeding (>80 mL).
- Flow Volume: around 25–80 mL
- Light Flow (25–35 mL):
- May require changing a pad or tampon every 6–8 hours.
- Minimal clotting; blood may appear light red or brown.
- Often described as “spotting” or “light bleeding.”
- Moderate Flow (35–50 mL):
- Pads or tampons may need changing every 4–6 hours.
- Some small clots (less than 1 inch) may be present.
- Blood is typically bright to dark red.
- Heavy Flow (50–80 mL):
- Changing protection every 2–4 hours.
- Frequent clots, possibly up to 1 inch in diameter.
- May feel like “gushing” or “flooding” during peak days.
- Light Flow (25–35 mL):
Signs of Abnormal Periods
- Menorrhagia/Heavy Bleeding:
- Irregular Cycles:
- Cycles are generally considered irregular if they’re happening more often than every 21 days, less often than every 35 days, or the total length of cycles (from the start of one period to the start of the next) changes by more than 7 days.
- Not having periods (amenorrhea) or having infrequent periods (oligomenorrhea) can be caused by having a very low body weight (often as a result of eating disorders, cancer treatment, intense exercise, etc.) or other conditions like thyroid dysfunction or PCOS (polycystic ovary syndrome).
- Cycles less than 21 days in length, heavy periods, or bleeding between periods can cause anemia and may be warning signs of other conditions like endometriosis, thyroid dysfunction, or reproductive cancers.
- Unusual Symptoms:
- Bleeding between periods or after sex. Spotting or bleeding between periods can be a sign of things like PCOS, fibroids, polyps, sexually transmitted infections, or reproductive cancers.
- Dizziness, extreme fatigue, or fainting during menstruation, which could be a sign of anemia.
When to Seek Medical Advice
Changes in your periods can be more than just a nuisance. They can signal concerning changes in your health. If you notice changes in your cycle length or flow that last for at least three months, or if your symptoms are affecting your everyday life or causing you distress, it might be a good time to reach out to your healthcare provider. Be sure to tell your provider if you have a history of things like bleeding disorders, PCOS, thyroid disease, or other health conditions, as these can contribute to an abnormal menstrual cycle.
Conclusion
Tracking your cycle can be a helpful tool to know if your menstrual cycles are normal and to help you notice any changes. Educating yourself about menstrual cycles and speaking openly with your healthcare provider are some ways you can take charge of your menstrual health and overall wellbeing. Remember that everyone is different, so talk to your provider about what’s normal for you.
Reviewed by the Ovia Health Clinical Team
Sources
- “UofL Health: Louisville Hospital and Health Care System Serving Kentucky and Indiana.” UofL Health | Louisville Hospital and Health Care System Serving Kentucky and Indiana, 14 Nov. 2025, uoflhealth.org/.
- “Menstruation Tracking.” Hemophilia Federation of America, 29 July 2024, www.hemophiliafed.org/resource/menstruation-tracking/.
- Easwaran, Kavitha Lakshmi. “Period Blood Clots Pictures: Normal vs Abnormal Explained.” Sai Speciality Center, 3 July 2025, www.saispecialitycenter.com/blog/period-blood-clots-pictures/.
- “Heavy and Abnormal Periods.” ACOG, Oct. 2020, www.acog.org/womens-health/faqs/heavy-and-abnormal-periods.
