The number of American women getting mammograms to screen for breast cancer has declined considerably, making health officials worry that the trend could worsen.

A new study published in the June 15, 2007 issue of Cancer, an American Cancer Society journal, says that mammography rates have declined in the US in the past 7 years. The worrisome aspect of this issue is that mammograms are instrumental in detecting cancer in its early stages, hence making recovery possible.

According to the study, the number of women over 40 saying they had a mammogram within the past two years has decreased from 70% in 2000 to 66% in 2005. Mammograms have become increasingly popular since the 1980s, compared to the 39% mammography rates of women aged 40 or older in 1987.

Dr. Nancy Breen of the National Cancer Institute, the study’s lead author, said: “It's quite an unusual and disconcerting finding. It comes as a surprise because there's no reason you'd think there'd be a drop in mammography.”

Dr. Breen and her colleagues based their research on a scientific survey of approximately 10,000 US women 40 and older by the Centers for Disease Control and Prevention.

Analyzing the data, they found that while there was a steady rise in mammography rates from 1987 to 2000 and relative sameness from 2000 to 2003, in 2005, the rates dropped 4%, Dr. Breen said.

Declines were significant in women over 50 and in women from higher socio-economical backgrounds.

The researchers said that the decreasing rates of mammography could be due to lack of health insurance and not enough promoting of mammography as a way for women to take care of their health.

There has been some confusion lately on the topic of mammograms, especially for women in their 40s, as they are advised either to undergo mammograms or to take in consideration a number of risks associated with the procedure.

The American College of Physicians issued a new set of guidelines in April, warning that mammograms may be more benefic for women in their 50s and older than to 40-somethings.

Among the risks mentioned by the college are exposure to radiation and unnecessary biopsies, surgery and chemotherapy.

The ACP emphasized that breast cancer risk varies from one woman to another, as do the potential advantages and disadvantages, thus urging women to discuss the issue with their doctors.

Advocates for mammograms consider them crucial for detecting cancer in an early stage, when it is especially treatable.