For most women, a normal menstrual cycle ranges from 21 to 35 days.1 However, 14% to 25% of women have irregular menstrual cycles, meaning the cycles are shorter or longer than normal; are heavier or lighter than normal; or are experienced with other problems, like abdominal cramps.2 Irregular cycles can be ovulatory, meaning that ovulation occurs, or anovulatory, meaning ovulation does not occur.
The most common menstrual irregularities include:
- Amenorrhea (pronounced ey-men-uh-REE-uh) or absent menstrual periods:3,4,5,6 When a woman does not get her period by age 16, or when she stops getting her period for at least 3 months and is not pregnant.
- Oligomenorrhea (pronounced ol-i-goh-men-uh-REE-uh) or infrequent menstrual periods: Periods that occur more than 35 days apart.4
- Menorrhagia (pronounced men-uh-REY-jee-uh) or heavy menstrual periods:3,4,7 Also called excessive bleeding. Although anovulatory bleeding and menorrhagia are sometimes grouped together, they do not have the same cause and require different diagnostic testing.7
- Prolonged menstrual bleeding: Bleeding that exceeds 8 days in duration on a regular basis.4
- Dysmenorrhea (pronounced dis-men-uh-REE-uh): Painful periods that may include severe menstrual cramps.8
Additional menstrual irregularities include:
- Polymenorrhea (pronounced pol-ee-men-uh-REE-uh): Frequent menstrual periods occurring less than 21 days apart4
- Irregular menstrual periods with a cycle-to-cycle variation of more than 20 days4
- Shortened menstrual bleeding of less than 2 days in duration4
- Intermenstrual bleeding: Episodes of bleeding that occur between periods, also known as spotting4