(RxWiki News) Intrauterine devices (IUD) have been controversial. In fact, there has been a belief that the birth control device was a risk factor for cervical cancer. New research shows just the opposite association.
In the largest study of its kind, researchers found that women who use IUDs have half the risk of cervical cancer as women who have never used the device.
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This study involved reviewing the records of some 20,000 women around the world. The research was aimed at assessing the effects IUDs had on the risks of developing cervical human papillomavirus (HPV) and cervical cancer.
Xavier Castellsagué, researcher of Virus and Cancer research group at IDIBELL and colleagues examined and analyzed data from ten cervical cancer studies conducted in eight countries and 16 HPV prevalence surveys involving women on four continents.
The study found the risks of HPV infection are not affected by IUD use. However, women who used IUDs had a significantly decreased risk of developing cervical cancer. These findings held true for both major types of cervical cancer.
The likelihood of developing squamous-cell carcinoma was reduced by 44 percent and adenocarcinoma and adenosquamous carcinoma risks were down 54 percent in women who used IUDs versus those who had never used them.
An interesting finding showed that the length of time an IUD was used did not enter into the equation. Risks were reduced by almost half in the first year it was used and continued to be decreased even after 10 years of use.
The authors note that the IUD does not protect against HPV infection, which causes cervical cancer. However, the device may affect the chances of HPV turning into cervical cancer.
Causes for this protective effect are not clear, but authors offer a variety of possible explanations. The process of inserting or removing the device could destroy precancerous lesions. This process could also start a long lasting immune response that reduces the risk of HPV progressing into cancer.
This study was published in the September, 2011 issue of The Lancet Oncology.