If the Pill were to be invented today, getting a licence would be a difficult if not impossible task. Since the 1960s we have become much more cautious about medicines, especially those for healthy people.

Taking a drug that alters body chemistry for a long time when there are effective alternatives available would not seem a good idea to the regulators. Carrying out trials in the Third World, as was done to prove the efficacy of the Pill on 6,000 women in Puerto Rico and Haiti, would be unacceptable.

As an advisory committee of the US Food and Drug Administration remarked in the mid1960s, never would so many people take such a potent drug voluntarily over such a long period for a reason other than to cure disease. It said: “Since probably no substance, even common table salt, can be taken over a long period of time without some risk”, the potential side effects “must be recognised and kept under continual surveillance”.

Times have changed and risks loom larger than they did. This is why claims about the male Pill never quite come true. Tampering with hormones today strikes most drug companies as a risk they would rather not take.

There were cautionary voices raised in the 1960s, but they were largely ignored. The advantages seemed so overwhelming that if there was a risk it was one that many women were willing to take, at least for a short time.

Their judgment seems to have been borne out by events. Today’s report is not the first to provide reassuring news. A study published last year also found reduced risks of the main gynaecological cancers.

But the picture is not all positive. The new study covers women who used the Pill for an average of less than four years up to 40 years ago. With the exception of a sizeable minority who used it for more than eight years, they showed no ill-effects. But studies of current users have found increased risks of cancer of the cervix, breast and liver compared with nonusers.

The breast cancer risks revert to normal within about ten years of stopping, and the study suggests that liver cancer risks also fall. Cervical cancer rates may remain higher than normal, though the result is not statistically significant.

Cancer is not the only worry. In the early years fears about blood clots, heart attacks and strokes inspired exhaustive research. But these fears were largely laid to rest by low-dose pills. What remains are a number of side-effects that are less serious, such as bleeding between periods and mood changes, including depression. Some women may put on weight and suffer breast tenderness or dry eyes. But these problems usually subside within the first three months of use.

The Pill prevents heavy and irregular menstrual periods, a common cause of anaemia that can lead to the need for hysterectomy in older women. So the verdict is that the developers of the Pill did a good job. They helped to liberate a generation of women without doing them any harm.

Turbulent history

The contraceptive pill has been the subject of endless studies:

1960s Shortly after it came on the US market reports warned of side-effects such as blood clots, strokes, heart attacks and diabetes, but there were no conclusive findings. The number of American and British users continued to rise

1970s Scientists found that smoking contributed to blood-clotting in Pill users and that lower doses reduced risk of clots and side-effects such as weight gain, headaches and nausea

1972 The Pill was found to cause breast cancer in female monkeys

1983 Three separate studies found a link to breast cancer. The studies showed a 125 per cent increased risk of breast cancer for women who used hormonal contraceptives for four years or more before having a full-term pregnancy. The number of users began to drop

1990s A series of studies, including one published in The Lancet involving 53,297 women with breast cancer in 25 countries appeared to confirm the link

1995 A government warning about seven brands of Pill led to another scare. The 1.5m women taking these brands were told they doubled the risk of thrombosis

2000 A study in the British Medical Journal said that the Pill did not cause blood clots and that the 1995 scare was unfounded