University of Oregon (UO) researchers said they were surprised to find that nearly 20 percent of young women choose to delay or skip their monthly periods by deviating from the instructions on their birth control pills and other hormonal contraceptives.

Most women who alter their cycles do so for convenience rather than to avoid menstrual symptoms, according to the UO study, which was published this week in Contraception. The research team also noted that most women learn about the option to alter their cycles from non-medical sources.

"These findings emphasize the need for healthcare providers to carefully interview combined hormonal contraceptive users on how they are using their method," said researcher Christopher Minson, a human physiology professor at UO, in a press release.

Why Do Women Alter Their Cycles?

Women's individual experiences and attitudes about menstruation play an important role in determining their interest in menstrual suppression, according to the National Women’s Health Network.

The media has also contributed to women's opinions about their periods. Seasonale, an extended cycle oral contraceptive, was first advertised in 2003 by a prominent spokeswoman, Sex and the City writer Candace Bushnell.

“When you think about what women have accomplished with thirteen periods a year, think about what we can accomplish with only four,” Bushnell said in the ads.

This kind of advertising hints that taking the pill is more of a lifestyle choice than a medical decision. But even before extended cycle contraceptives reached the market, some companies did consider women's attitudes and feelings. 

When birth control pills were first introduced, drug companies wanted to minimize the perception that they changed the menstrual cycle, so they offered 21 days of hormone pills along with seven days of placebo pills.

Is Changing Your Menstrual Cycle Safe?

Research shows that reducing the occurrence of periods is safe and can even be beneficial. Endometrial and ovarian cancer risk decreases in women who use birth control pills, though hormonal pills may slightly increase the risk of breast and cervical cancers.

According to the Association of Reproductive Health Professionals, "the adjustment of the menstrual cycle, or menstrual suppression, via hormonal contraception allows women to have less frequent periods and avoid bleeding at inconvenient times in their lives...There is an absence of evidence to support regular menstruation as medically necessary, as well as an absence of evidence to suggest that suppressing menstruation is deleterious to a woman’s health."

The recent study included undergraduate and graduate students at UO. About 17 percent reported altering their scheduled bleeding pattern by extending the use of birth-control pills, vaginal contraceptive rings, or contraceptive patches.

Women who said they would prefer not to have menstrual periods were less likely to alter their cycles than those who said they would prefer one per year, according to the researchers. A woman who would prefer one cycle per year had a 17 percent greater probability of modifying her birth control regimen than one who preferred a menstrual period every three months or never.

"We found that it is possible to identify some of the specific characteristics of women in a college population who may be more or less likely to practice scheduled bleeding manipulation," said Dr. Paul Kaplan of the University Health Center and Oregon Health and Sciences University in a press release. "This study provides information about the motives, beliefs and influences relating to this practice."

Health care providers should improve patient education and start a dialogue about the hormonal contraception regimen that is best-suited to a patient's individual needs and desires, the researchers said.

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