22 July 2005
Fertility Drugs Ineffective For Some Women
Medications commonly referred to as fertility drugs may be ineffective for women who lack a gene called the estrogen receptor beta says a new study. The findings showed that fertility drugs did not improve ovulation rates in mice that were genetically engineered to lack the estrogen receptor beta gene. The mice lacking this receptor are more likely to exhibit infertility or sub-fertility, including producing fewer offspring, or having less frequent pregnancies. Fertility drugs did not improve the ovulation rates.
The estrogen receptor beta gene regulates the effects of estrogen hormones and plays a critical role in ovulation. The study, appearing in Endocrinology, suggests that women who do not have this gene may benefit more from alternative infertility treatments.
The role played by the estrogen receptor beta gene was unknown before this study. "The beta estrogen receptor plays a role in moving the egg outside the ovary so it can be fertilized," said Kenneth Korach, at the National Institute of Environmental Health Sciences (NIEHS) where the research was conducted. Interestingly, the estrogen receptor beta is also known to respond to environmental and dietary chemicals that can mimic the effects of estrogen and stimulate the body's natural hormones. One example is a common component of soy products - genistein. The researchers suggest that such environmental exposures could interact with estrogen receptor beta and possibly alter ovarian function in women.
The researchers believe that a simple blood test will soon be able to provide enough information to determine if the gene is not functioning. The results of this blood test, coupled with information from other medical tests, will help determine appropriate treatment options. "If we can help couples understand the reasons for their infertility, doctors can further define their treatment options, help them to minimize the expense and risk of taking drugs that may be less effective for them, and increase their chances of having a safe and healthy child," said NIEHS Director David Schwartz.