Birth Control Pill Safety Concerns : Part 2

by Food and Drug Administration (FDA)

(Page 2 of 3)

FDA Calls for Study

However, FDA expressed reservations about the pill's "very infrequent but serious" side effects and the lack of scientific data to adequately assess those side effects. It called for a large, case-control study of the relationship between oral contraceptives and blood clotting.

As for cancer, the advisory committee concluded the pill hadn't been in use long enough to draw valid conclusions about its carcinogenic effects. For example, it would be at least another 10 years before the risk of uterine cancer could be accurately assessed.

The advisory committee's findings on the possible relationship between the pill and blood-clotting and cancer were supported by a World Health Organization scientific group, which independently had reached the same conclusions.

However, by 1968, amid further reports of blood clots and new evidence from British studies showing an increased incidence of blood clots among women taking the pill, FDA added information about the results of those studies to the product labeling for oral contraceptives. A year later, the agency again revised the labeling, this time to include the results of U.S. studies that supported the British findings.

By 1969, ongoing research had revealed that the risks of blood clots, heart attack, and stroke were directly related to the amount of estrogen in the various versions of the pill. Research also showed that the same rate of contraceptive effectiveness could be maintained with only 50 mcg of estrogen. By that time, 7.5 million women were using oral contraceptives — up from 408,000 women in 1961.

As the 1970s began, FDA issued a bulletin to doctors about the danger of blood clots. It advised using the lowest effective dose of estrogen possible when prescribing oral contraceptives. The agency also revised the product labeling once again to include the "lowest effective dose" recommendation. And, for the first time, FDA required that information for patients about the drug's risks be included in every package of oral contraceptives.

'Mini-Pill' Introduced

In the early 1970s, the "mini-pill," an oral contraceptive containing only progestin, was introduced. Unlike the estrogen-progestin pill, which works primarily by suppressing ovulation, the mini-pill works by creating changes in the cervix and uterus that make it difficult for sperm to unite with an egg. Since mini-pills contain no estrogen, they pose few of the risks associated with the combination pill. However, mini-pills have two drawbacks: They cause irregular bleeding in some women, and they have proven to be less effective in preventing pregnancy. As a result, their use has been limited.

By the mid '70s, most women who used oral contraceptives were taking pills that contained 50 mcg or less of estrogen — a considerable decrease over the 100 to 150 mcg of the '60s. The amount of progestin in the pills had also decreased over the years from the original 10 mg to between 2.5 mg and 0.15 mg.

Between 1973 and 1974, FDA approved several low-dose pills containing as little as 20 to 35 mcg of estrogen. Most pills prescribed today contain 30 to 35 mcg of estrogen and 0.5 mg to 1 mg progestin.

In 1982, a new version of the pill, called the "biphasic" pill, was introduced. Two years later, three "triphasic" pills were introduced. These "multiphasic" oral contraceptives are low-dose pills in which the ratio of progestin to estrogen changes during the 21 days the pill is taken.

By 1986, use of high-dose estrogen pills had been drastically reduced — to 3.4 percent of the oral contraceptive market.

Nevertheless, some 400,000 women were still using high-dose estrogen pills. Most were between 30 and 39 years of age, the age group most at risk of serious side effects.

High-Dose Estrogen Pills Withdrawn

In 1988, at FDA's urging, the three drug companies still manufacturing high-dose estrogen oral contraceptives voluntarily withdrew from the market all remaining products containing over 50 mcg estrogen.

The latest development in the 30-year saga of the pill was its approval last year for use in healthy, non-smoking women over 40. The impact of this move, in terms of the number of women who will choose to continue or start using the pill after they turn 40, remains to be seen. But an estimated 1 million to 1.5 million women between 40 and 54, including the baby boomers, could be affected.

About the Author

www.fda.gov
FDA is A United States government body that oversees medical devices, including contact lenses, intraocular lenses, excimer lasers and eyedrops. In the US, these products must be approved by the FDA before they can be marketed.