Why Periods? False Hopes, Popes, and the “Grandfathered” Withdrawal Bleed

The birth control pill and other hormonal contraception are popular. Menstrual periods are not. Hormonal contraception can be used to suppress menstruation — so why isn’t this method, called “continuous contraception,” more popular?

For decades, packets of birth control pills have typically contained 21 “active” pills and seven “placebo” pills. These placebos — sugar pills — trigger bleeding (which most people think of as a menstrual period, even though it’s technically called a withdrawal bleed). Because menstruation is natural, some people think this withdrawal bleed must somehow be healthier. But there are actually no health benefits — and it might also increase risk for pregnancy.


There is no reason to have a period when on the birth control pill — unless you want one.


Last month, British medical guidelines were revised to recommend continuous use of the birth control pill — that is, with no week-long “break” designed to trigger a withdrawal bleed. We could have been skipping our periods since the Pill was introduced in 1960 — so why is it only now that we are coming to see them as optional?

A flurry of recent articles has touted a rather conspiratorial claim: that the monthly bleed was included in an attempt to make the Pill more palatable to the pope. The Telegraph quoted reproductive health expert John Guillebaud: “John Rock devised [the week of placebo pills] because he hoped that the pope would accept the Pill and make it acceptable for Catholics to use. Rock thought if it did imitate the natural cycle then the pope would accept it.”

Many journalists, pundits, and bloggers have expressed outrage that we’ve been putting up with decades of unnecessary bleeding (and all the attendant pain, headaches, and missed work) just because of an unsuccessful attempt to appease the pope before most women of reproductive age were even born. But the history of the placebo week is more complicated.

Treating Infertility

Hormonal contraception owes its powers to a hormone called progesterone, which essentially tricks the body into thinking it’s pregnant and doesn’t need to release eggs. As far back as 1937, scientists confirmed this idea by injecting rabbits with progesterone to see if they stopped ovulating. Whether it occurred to them that progesterone could be harnessed as birth control is lost to history — contraception was deeply taboo, and there were laws against so much as sharing information about it.

Gregory Pincus, Min-Chueh Chang, and John Rock, three scientists employed by Margaret Sanger and Katharine McCormick to develop the birth control pill.

Gregory Pincus, Min-Chueh Chang, and John Rock, key developers of the birth control pill

The idea that people using the Pill should keep menstruating arose early in its development. In 1952, scientist Gregory Pincus met gynecologist John Rock, who was experimenting with progesterone injections with the goal of treating infertility. Rock’s treatment involved blocking ovulation for two years, under the hypothesis that a period of “rest” would lead to a “rebound” that would jump-start fertility.

Once on the experimental therapy, Rock’s infertile patients’ periods came to a halt, accompanied by side effects like nausea and breast tenderness, which mimicked pregnancy — especially at the high doses they were receiving, which were hundreds of times higher than the dosages of hormones contained in modern-day birth control pills. Symptoms like missed periods and morning sickness convinced many patients they were pregnant. It was a heartbreaking source of false hope for those hoping to conceive.

Pincus suggested that instead of administering progesterone daily, it be administered for 21 days with a seven-day reprieve, allowing the subjects to experience regular periods. The benefit was clear: Patients would receive a monthly signal that they were not pregnant, protecting them from the false hope that a missed period would give them.

These fertility patients wanted their periods — but so did Big Pharma. Pincus received some early funding from Searle, a pharmaceutical company now owned by Pfizer, under the condition that the drugs he was developing wouldn’t interfere with the menstrual cycle. That, said one executive, would be “going against Nature.”

Preventing Pregnancy

Even though Rock had been using progesterone to treat infertility, it was obvious that a drug that could suppress ovulation could be used to create a new type of contraceptive — something that didn’t require a partner’s cooperation and was easy to use, in contrast to condoms and diaphragms. With funding from Planned Parenthood Federation of America and former suffragette Katharine McCormick, Pincus and Rock’s attention quickly turned to creating a birth control pill.

By the time human clinical trials for the Pill began, the “placebo week” was entrenched. And it made sense, given the cultural context. Clinical trial participants were not trying to get pregnant, making a missed period an alarming sign of an unwanted pregnancy rather than a source of false hope to someone struggling with infertility. They also might have been skeptical that these experimental pills would actually work, but a monthly period could be the reassurance they needed that the Pill was functioning as hoped. That reassurance was important, given that they couldn’t just pop down to the corner drugstore for a pregnancy test (those weren’t available until 1976). At that time, confirming a pregnancy required a visit to a doctor —  most people just relied on signals from their body, chief among them a missed period.

The birth control pill was approved in 1960, a decade of great changes within the Catholic Church. The church had explicitly forbidden birth control in 1930, making the rhythm method the strategy of choice for observant Catholics trying to control their fertility. But many lay Catholics and clergy were clamoring for this ban to be lifted. Dr. Rock, himself a devout Catholic, wrote an entire book hoping to convince the Vatican to accept the Pill. In 1964, the pope assembled a commission to study the issue, and many people anticipated that the 1930 ban would be reversed. But in 1968, to the disappointment of many Catholics, the pope ultimately upheld the ban — against the wishes of the majority of theologians and cardinals on his commission. The decision was unpopular, and many Catholics used the Pill anyway.

Using Birth Control Today

These days, several types of hormonal birth control — the Pill, the ring, and the patch — are generally taken for three weeks, followed by a week-long break that triggers a withdrawal bleed. But users have known for decades that they can skip this break — and along with it, their periods — by starting a new pack of pills, inserting a new ring, or applying a new patch.

The inclusion of the placebo week in the first generation of birth control pills makes sense — people without access to home pregnancy tests, using a pill that was still a recent innovation, might have relied on the peace of mind provided by a period. But by now, most of us trust hormonal contraceptives as among the most reliable out there — we’ve been using them for generations and know they work.

Though some of us might still want the reassurance of a monthly period, there is a great argument to be made that continuous contraception should be the default: Packs of pills should last for 28 days, not 21; the ring should last for four weeks, not three; and the patch should come in boxes of four, not three. We should be able to get a full month’s supply of birth control, not prescriptions that need to be refilled every 21 days.

Don’t try to skip periods without talking to a health care provider first, because some birth control pills may not lend themselves to continuous usage. Experts at your local Planned Parenthood health center can talk to you about using birth control to skip periods and answer other questions you have about contraception.

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