Oral contraceptives protect women from ovarian and endometrial cancer

Courtesy Uppsala University photo credit Matton

CANCER DIGEST – Dec. 19, 2020  – Women who had taken oral contraceptives had a 50 percent lower risk of ovarian and endometrial cancer 15 years after discontinuing the drugs, a new Swedish study has found. At the same time the women in the study had only a small increased risk of breast cancer.
Led by Professor Asa Johansson at the Department of Immunology, Genetics and Pathology at Uppsala University in Sweden, the study involved analyzing data from 250,000 women born between 1939 and 1970. The researchers compared the women who were diagnosed with cancer with those who did not have cancer. The results were published in the December 2020 journal Cancer Research.

They found that odds of being diagnosed with ovarian or endometrial cancer were significantly lower among women who had ever used contraceptives and the longer they used the pill the lower the chance of cancer. In addition, the protective effect was seen in the women as long as 35 years after their last use of the contraceptives.

While there have been studies showing an increased risk of breast cancer among oral contraceptive users, the researchers in this study found the risk was only slightly higher.

“Surprisingly, we only found a small increased risk of breast cancer among oral contraceptive users, and the increased risk disappeared within a few years after discontinuation,” Johansson said in a press release. “Our results suggest that the lifetime risk of breast cancer might not differ between ever and never users, even if there is an increased short-term risk.”

Oral contraceptives became widely available in the 1960s and approximately 80 percent of women of reproductive age in Western Europe have used them at some point in their lives. In the US the number is estimated at 60 percent according to the Guttmacher Institute, a leading research and policy organization committed to advancing sexual and reproductive health and rights in the United States and globally.

Oral contraceptives include estrogen and progestin, which are synthetic forms of the female sex hormones. Taken in oral form the contraceptives prevent ovulation and thereby protect against pregnancy.

Sources: Uppsala University press release, the journal Cancer Research, and the Guttmacher Institute