Since the introduction of the birth control pill, it has been available only with a doctor's prescription. Though there has been an effort in recent years to make it available over the counter, British medical researchers suggest doing so will not reduce unwanted pregnancies.

Their research is published online at, the Web service of the British Medical Journal.

Sarah Jarvis from the Royal College of Physicians argues that it is a lack of daily compliance with taking oral contraceptives that is partly responsible for the high rates of unintended teenage pregnancies in the UK.

Studies have shown that nearly half of all women taking the oral contraceptive pill miss one or more pills in each cycle, and nearly a quarter missed two or more. These women are three times more likely to get pregnant unintentionally than those who take the pill consistently.

She points out that the availability of emergency contraception without prescription has done little to change the rate of teenage pregnancies.

Jarvis believes that the solution lies in long acting reversible contraceptives such as the coil, or those that can be placed under the skin or injected. They last between three months and three years, and because they are not dependent on patients taking them correctly, are much more reliable than oral contraceptives, she adds.

"Increased uptake of reliable, non user-dependent methods, rather than making a potentially unreliable method of contraception more easily available, has to be the key," she concludes.

But Dr. Daniel Grossman of Ibis Reproductive Health argues that the requirement for a prescription is a barrier to oral contraceptive use in some women.

He says if governments are committed to reducing rates of unintended pregnancies and maternal deaths in the developing world, increased access to safe oral contraceptives for all women at low or no cost is vital.