LYON, France — A group of international scientists under the aegis of the World Health Organization has concluded that use of oral contraceptives constitutes a definite risk of cancer.

However, the risk is not great enough to get the organization to recommend any change to the United Nations’ family planning programs.

But Catholic medical experts say the findings should induce health authorities in the United States and in other countries to rethink their promotion of the contraceptive pill, given the mounting evidence of the dangers it poses to the health of women.

Women increase their risk of breast, cervical and liver cancer if they use oral contraceptives, according to a July 29 press release by the Lyon, France-based International Agency for Research on Cancer (IARC), which is part of the World Health Organization (WHO). Other recent studies show the greatest cancer risk is to young women, particularly teenagers, who use the pill.

“These conclusions are of enormous public health importance, since it is estimated that worldwide, more than 100 million women — about 10% of all women of reproductive age — currently use combined hormonal contraceptives,” said Dr. Gian Luigi Gigli, president of the World Federation of Catholic Medical Associations, headquartered in Vatican City.

An international ad hoc working group of 21 scientists from eight countries surveyed the existing scientific literature at a June meeting but did not engage in any independent research. Many epidemiological studies have investigated associations between the use of combined oral contraceptives and the onset of cancer.

The scientists published a summary of their findings in the August 2005 issue of Lancet Oncology, a British medical journal. Worldwide, an estimated 300 million women have used oral estrogen-progestagen contraceptives at some time, according to the report.

‘Carcinogenic’

According to the Lancet Oncology article, “An IARC Monographs working group has concluded that combined estrogen-progestagen oral contraceptives … are carcinogenic to humans [Group 1], after a thorough review of the published scientific evidence,” Group 1 is the highest cancer-risk classification.

Hormone therapy for menopausal symptoms was placed within the same category of Group 1 cancer risk by the working group in the same report.

“What is significant is that they are using terminology to call it a carcinogen,” said Dr. Chris Kahlenborn of The Polycarp Research Institute in Altoona, Penn., an organization that promotes ethical research and dissemination of medical information in conformity with Catholic teachings. “I am surprised, very surprised.”

Ovarian and endometrial cancer risk declines with use of oral contraceptives, the working group also noted. Both findings had been previously reported.

“Because use of combined contraceptives heightens the risk of some cancers and reduces that of others, it is possible that the overall net public-health outcome could be beneficial, but a rigorous analysis is needed to show this,” the World Health Organization ad hoc group said in their report. “Such an analysis is outside the scope of an IARC monograph meeting.”

The warning about elevated risks of some cancers when using oral contraceptives is the first such statement from the World Health Organization, but it follows acknowledgement in 2003 by the National Cancer Institute of elevated breast cancer rates tied to use of the pill, particularly among women under 20.

In addition, a 2004 presentation to the American Association for Cancer Research by a professor from the University of Lund in Sweden found a sharp increase in breast cancer risk among young women who use the pill. The incidence rose 17% for each year a woman under 20 used oral contraceptives, according to the study of 259 women diagnosed with invasive breast cancer by the age of 40.

While the World Health Organization, which is the U.N.'s specialized agency for health, has not called for oral contraceptive use to be discontinued, the acknowledgement of cancer risks is a break from the pro-pill position of another prominent U.N. agency. The U.N. Population Fund promotes use of oral contraceptives as one of several contraceptive options.

In the United States, minor children can obtain artificial contraception in all 50 states without parental knowledge — in many cases funded by the states and in other cases paid for by the parents’ health insurance policies, according to Mike O'dea, executive director of the Southfield, Mich.-based Christus Medicus Foundation.

On its website, the Planned Parenthood Federation recommends use of the pill as one of several forms of artificial contraception, dismissing the risk of cancer from use of oral contraceptives under a heading of “Myth No. 5.”

“It is particularly irresponsible that Planned Parenthood is not warning teenagers of the risks involved with pill use,” said Peter McFadden of the marriage-preparation-focused Love and Responsibility Foundation of Cold Spring, N.Y. “Planned Parenthood's website for teenagers [TeenWire.com] responds to a 14-year-old girl nervous about the pill's possible side effects by telling her the pill is ‘safe.’ Nowhere is she told that teen use of the pill is tied to early onset of breast cancer.”

Planned Parenthood did not return a telephone call for comment. According to Planned Parenthood's financial statements, it receives about two-thirds of its income from sale and distribution of artificial contraception — approximately $200 million in 2004.

The Catholic Church teaches artificial contraception is morally unacceptable. The Catechism of the Catholic Church states that “every action which, whether in anticipation of the conjugal act, or in its accomplishment, or in the development of its natural consequences, proposes, whether as an end or as a means, to render procreation impossible is intrinsically evil” (No. 2370).

The president of the World Federation of Catholic Medical Associations is heartened by the World Health Organization-sponsored group's conclusions.

“Oral contraceptives are presented as an easy response for an important problem,” said Gigli in an e-mail to the Register. “The United Nations has been actively promoting [and even imposing on some developing countries] a policy of so called ‘reproductive health.’ It is a package including abortion and OCs (oral contraceptives) as a ‘must’ of civilization and democracy.”

Said Gigli, “It is important that for the first time WHO, a U.N. agency, invites [us] to balance benefits and risks and acknowledge the serious risks of cancer implicit in the use of OCs.”

Valerie Schmalz is based in San Francisco, California.