A study claiming the Pill offers protection against risk of heart disease has been found to be flawed. Theresa Judge reports.
The contraceptive pill is safe but it does not offer protection against heart disease. That is the consensus among doctors after conflicting media reports late last year about the effects of taking the Pill.
"We are nowhere near saying that the Pill protects against heart disease and I don't believe we will ever say that," according to Dr Mary Condren, a lecturer in women's health at the Royal College of Surgeons in Dublin.
However, a study that claimed to have found that taking the Pill for long periods protected against heart disease and cancer was widely reported throughout the world at the end of October. It has since emerged that the study was flawed.
The findings were based on data collected by the Women's Health Initiative (WHI), which runs one of the world's largest studies into female health, but the WHI has rejected the conclusions drawn by the researchers and has demanded a retraction.
The acting director of the WHI, Dr Jacques Rossouw has been quoted as saying: "The researchers just looked at baseline data, which is very poor data These kind of results are just not credible. We've asked them to retract it, but it's up to them."
The controversial study was presented in October at a conference of the American Society of Reproductive Medicine in Philadelphia by researchers at Wayne State University in Detroit. Because it used data from more than 160,000 women, the findings appeared to be significant.
However, the research has not been published in any medical journal. Its authors say that they are working on getting it published in such a journal, but this would only be possible with the permission of the WHI.
Dr Rossouw's criticisms of the study centre on the fact that it relies to an extent on women's memories - the data was from women aged from 50 to 70 who would have taken the Pill many years earlier - and also the fact that only women who did not have cancer or cardiovascular disease would have enrolled in the trial. The WHI analysed the Detroit research but could not replicate its results.
Dr Mary Condren says the problem is that the findings had been picked up and reported by the lay press before being adequately discussed and analysed by medical professionals. She also points out that because women who are regarded as being at risk of heart disease are not generally prescribed the Pill, it would not be surprising therefore if those who do take the Pill are found to have a lower rate of heart disease.
Regardless of the discussion about this study, she says advice in relation to Pill use would not change. Women over 35 who smoke should not take the Pill.
"What we say is that the Pill is safe but that the women who use it may not be safe, in that they may be at risk of heart disease because of a number of factors," Dr Condren says.
"There are certain things in women's lives that put them at risk of heart disease - age, blood pressure, family history, cholesterol levels, and smoking. The Pill is yet another brick in the wall that can increase the risk of heart disease, but that is not to say that it will cause heart disease in an otherwise healthy woman," she added. She said the message to give to a 35-year-old smoker is that it is not the Pill that is the problem but smoking.
Prof John Bonnar, professor emeritus at Trinity College and a consultant obstetrician and gynaecologist, says the findings of any study had to be examined closely before being accepted. "You can't bring out one study and throw out everything that went before it."
Prof Bonnar says that very large trials carried out in the UK in the 1970s had shown a link between Pill usage and cardiac disease among older women who smoked. He would be unhappy about putting a smoker aged over 35 on the Pill.
That given the low doses of hormones in today's combined oral contraceptive Pills doctors are more confident about allowing healthy non-smokers to take them into their 40s, he notes. Prof Bonner believes benefits of the Pill, such as its effectiveness in treating heavy menstrual bleeding - a common problem among women in their 40s - had to be weighed against possible risks. "It's a very individual thing and it has to be looked at holistically."
Data on cancer, which was universally accepted, showed that Pill usage could lead to a 50 per cent reduction in ovarian cancer, and also to a reduction in uterine cancer.
It was known that the number of cycles a woman had between puberty and menopause was related to incidence of ovarian cancer, so as a result taking the Pill could reduce it, he stresses.
The medical director of the Dublin Well Woman Centre, Dr Shirley McQuade, says that in prescribing the pill the issue of whether it provided any protection against heart disease certainly never arose.
While there had been a belief that perhaps oestrogen could provide protection against heart disease, "the bulk of research is saying that it isn't protective". The danger associated with prescribing the Pill to over-35s who smoked was due to the increased risk of blood clots in the legs and lungs.