A new study has confirmed that fertility treatment in women does not increase their risk of developing breast cancer. It was long suspected that women who opt for in vitro fertilization (IVF) are at an increased risk of breast cancer.

The researchers from the Netherlands Cancer Institute based their findings on a study of decreased estradiol and progesterone levels along with strongly elevated hormone levels. The team studied whether this increases the risk of the disease.

The team conducted their study on a group of 19,000 women who opted for an IVF treatment between 1980 and 1995. The age at which the team followed up with the women was 54, while that of the other group was 55.

Researchers found that out of more than 25,000 women involved in the study, 839 had invasive breast cancer, while 109 women have in situ breast cancer. The data derived from the Netherlands Cancer Registry indicated that the rate of breast cancer risk among women opting for IVF did not differ from the other group of subjects that either opted for other forms of fertility treatment or from the general population.

In addition, there was no difference in the rate of breast cancer risk when the researchers compared the use of different types of fertility drugs. The risk was not increased even after 20 or more years of IVF.

In fact, the team did find that the risk of developing breast cancer decreases in women who underwent seven or more cycles of IVF treatment, as compared to those who undergo only two or three cycles of treatment.

The researchers thus concluded that the long-term risk of developing breast cancer does not increase with this type of IVF regimen. The complete details of the study have been published in journal JAMA.