Review on December 01, 2009
Before and after menopause, a woman must maintain the right levels of hormones in her body to maintain a healthy lifestyle. A woman's menstrual cycle is an especially complex system involving the ovulation stage and the luteal stage. Estrogen levels are high in the woman's body right before she ovulated. A connection has been made between anovulation (when ovulation does not take place) and a possible decreased risk of breast cancer in women as high levels of estrogen may cause breast cancer. This study was conducted to determine whether or not infertility drugs may have an effect on the development of breast cancer.
It is surmised that women who have less ovulation cycles during their lifetime may in reality be at lower risk for developing breast cancer than women who have regular ovulation cycles. This hypothesis was created since breast cancer is associated with increased levels of estrogen and relatedly, estrogen levels increase just before ovulation. Progesterone hormones levels are decrease before ovulation but increase during the luteal phase of the menstrual cycle.
To ascertain whether ovulatory disorders diminished the risk of breast cancer and ovulation induction increased the risk of breast cancer, information was gathered from the Nurses' Health Study. Participants included 116, 671 female registered nurses from the ages of 25 to 42 years old. Infertility data was assessed every two years from 1989 to 2001. As this study was about fertility, women going through menopause were not considered.
Follow-up questionnaires were given to participants of the Nurses' Health Study biennially for the purpose of updating data on risk factors, medical events and infertility status. Specific questions asked whether or not the woman had tried to get pregnant for one year without unsuccessfully. They were also asked whether or not they had taken drugs to induce ovulation over the 2 year window. Participants were asked birth date, family history of breast cancer, weight at 18 years of age, height during the time the survey started, use of progesterone hormones and age of menopause of their mother. Doctors also took into consideration alcohol intake and use of oral contraceptives.
In the follow-ups, 1,357 women told of cases of diagnosed breast cancer. General results showed that women who had reported infertility due to ovulatory disorder had a noticeably lower incident of breast cancer than the women who reported no problems conceiving (during a 12 month period). The lowest incident of breast cancer was among infertile women (because of ovulatory disorder) who had taken ovulation – induction therapy.
The results of this study show a significant relationship between a decreased risk in breast cancer and the use of ovulartory inducing drugs. Women with menopause were excluded from this survey.