Is there a woman over the age of 18 anywhere who doesn’t know that taking the birth control pill can make her periods lighter and less painful? Most women know this, but not many know why. The news stories swirling around a new study about the pill and period pain will not enlighten them.

Photo credit: Ceridwen, Creative Commons 2.0

A 30-year longitudinal Swedish study has finally proved the worth of what is accepted practice in North America and Europe: the prescribing of combined oral contraceptives (COCs), or birth control pills with synthetic estrogen and progestin, to treat painful periods known clinically as dysmenorrhea.

Of course, pharmaceutical companies that manufacture COCs are probably eager for this research, as prescribing the pill for dysmenorrhea is still an off-label use in the U.S. (unlicensed use in the U.K.). Pill manufacturers may be able to use this finding to lobby the FDA (or equivalent agencies in other nations) to approve the pill as treatment for menstrual pain, leading to increased sales and insurance coverage. Perhaps that’s why news media have been treating this discovery as breaking news.

Take this headline: Yes, the Pill CAN ease the agony of period pain: Scientists confirm what millions of women already know, or this one: The pill ‘does ease period pain’, or this one: Combination oral contraception pills cut menstruation pain, or, really, any of these.

You can read the abstract of the study by Swedish researchers Ingela Lindh, Agneta Andersson Ellström and Ian Milsom, published this week in the journal Human Reproduction, here: The effect of combined oral contraceptives and age on dysmenorrhoea: an epidemiological study. The conclusions are simple: “COC use and increasing age, independent of each other, reduced the severity of dysmenorrhoea. COC use reduced the severity of dysmenorrhea more than increasing age and childbirth.”

Forget the age factor for the purposes of this discussion. The fact that COC use reduces the severity of dysmenorrhea is not astounding. This is old news. So says Dr. Steven Goldstein, an obstetrician/gynecologist at NYU Langone Medical Center in New York City, quoted in a USA Today story:

“The study results are not surprising. It’s gratifying to see researchers documenting scientifically what practitioners have been seeing for a very long time. The amount of discomfort from a woman’s period with a combination birth control pill is a fraction of what it is without the Pill. There is a diminution of pain from the Pill.”

What is astounding is what Dr. Goldstein, and other OBGYNs, didn’t say in responding to the study. That the reason the pill reduces menstrual pain is because the synthetic hormones in the pill shut down a woman’s own menstrual cycle. The “period” women experience when on the pill is technically known as a “withdrawal bleed,” brought on by seven days of placebo pills. While it feels like a period to menstruators, it is not the same physiologically as the period they experience when NOT on the pill. That’s why it doesn’t hurt as much.

The point is, the pill is too often credited with regulating the menstrual cycle. It does no such thing. The pill does not regulate any woman’s menstrual cycle; it supercedes it. This research, and the many news stories that reported it, once again ascribe power to the pill – this time the power to cut menstrual pain. This is an incomplete truth.