Birth control pills were a revolutionary advance in contraception back in the 1960s. They were unquestionably more effective and convenient than any other form of contraception.

In theory, only one woman out of 100 who took the Pill for a year became pregnant. This seemed like an acceptable failure rate to the FDA and to most women.

To achieve this level of protection, drug companies used high doses of hormones (estrogen and progestin). Women often experienced side effects such as breast tenderness, nausea, vomiting, headaches and weight gain. More serious complications included gallbladder disease, diabetes, high blood pressure and blood clots that caused heart attacks or strokes.

Fortunately, such adverse events were relatively rare. But with millions of women on birth control pills, cases began to add up. That’s why drug companies looked for ways to reduce the likelihood of side effects. Over the decades, hormone levels in oral contraceptives have dropped.

Low-dose birth control pills are less likely to trigger nausea and vomiting. The trade off, however, is lower effectiveness. Newer pills fail twice as often as earlier ones.

For women, this has become a balancing act. Lower dose pills are easier to tolerate, but they are less forgiving when it comes to forgetting. They must be taken at the same time every day. Skipping just one dose can result in pregnancy.

Drug interactions are also a significant concern. Other medications may reduce contraceptive effectiveness, as this reader discovered:

“I have two lovely children, and my husband and I did not want any more. I have been on birth control pills for four years, but now I am pregnant again. Abortion is not an option.

“I never missed a single pill. I am sure the antibiotic I took for a sinus infection interfered with my oral contraceptive. My doctor seems defensive and says I must have forgotten a pill. Are there any other drugs that can do this? I never want this to happen to me or anyone else again.”

We discuss medications that interact with birth control pills in our Guide to Estrogen: Benefits, Risks and Interactions. Anyone who would like a copy, please send $2 in check or money order with a long (no. 10) stamped (63 cents), self-addressed envelope: Graedons’ People’s Pharmacy, No. W-49, P. O. Box 52027, Durham, NC 27717-2027. It can also be downloaded for $2 from the Website:

The medical profession has been arguing for years about whether antibiotics can reduce oral contraceptive effectiveness. Studies have been inconclusive, but we have heard from women who insist that they never missed a birth control pill yet became pregnant when they took an antibiotic.

Other medications that can impact the Pill include headache medicines containing barbiturates, anti-seizure drugs and some antifungal medications. Even the herbal remedy St. John’s wort that may be taken for depression could reduce effectiveness.

Like walking a tight rope, choosing a birth control pill requires consideration of the potential consequences of pregnancy versus the risk of dangerous reactions. The FDA should require head-to-head comparative studies of contraceptives so women can make informed choices.

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  1. E C

    I have recently been advised to consider Ortho Lo dose BC Pills at 43 – already had gallbladder just removed last week after many years of illness – misdiagnosed. I am having and have been having almost all symptoms of perimenopause for about 7 years now – with them getting worse this past year. Nervous – WAS suggested that I take Paxil for my anxiety due to this physical illness I’ve been having. Suggest I slowly wean off and get lo dose estrogen – not sure what to do – non-smoker – get headaches not much caffeine non-drinker and non-recreational drug-user.

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