According to a recent study, women with the BRCA1 mutation should not delay their pregnancies because their fertility may quickly decline once they enter their 30s.
Women with a BRCA1 mutation should try to avoid delaying pregnancy until later in life, suggests researchers for the Kathleen Cuningham Consortium for Research into Familial Breast Cancer (kConFab).
Researchers studied the effects of both BRCA1 and BRCA2 mutations in women from Australia and New Zealand by looking at their anti-Müllerian hormones (AMH) concentrations, to determine if the presence of one of the mutations hindered fertility. AMH hormone levels can be used to access a woman’s ovarian reserve beginning at age 25, as well as being the best predictor of when that woman will hit menopause.
The study, published in the journal Human Reproduction, consisted of 693 participants, all of whom “either had a pathogenic mutation, splice site mutation or large deletion in BRCA1 or BRCA2 (‘mutation carriers’), or were a blood relative of a mutation carrier and had themselves been tested and found not to carry the identified family-specific mutation (‘non-carriers’).”
Additionally, the women were 25 to 45 years old, had two ovaries, no personal history of any cancer (excluding non-melanoma skin cancer), no history of primary amenorrhea and were not pregnant or breastfeeding.
Blood was taken from the women upon enrollment in the study and sent to a lab for testing, focusing on AMH concentrations in each sample. In addition to assessing AMH concentrations based on mutation status, a subsequent analysis was done correlating AMH concentrations with age.
AMH concentrations were found to be negatively associated with age, supporting the fact that women lose their fertility as they get older.
However, presence of the BRCA1 mutation causes lower counts of AMH, resulting in quickly declining fertility for women in their mid-thirties. It was determined that carriers of the BRCA1 mutation had about 25 percent lower AMH concentrations than non-carriers. This measurement of AMH shows these women have a reduced ovarian reserve.
The study’s authors state the difference in AMH concentrations is equivalent to a two-year age increase. For example, a 35-year-old woman with a BRCA1 mutation would have the fertility equivalent of a woman who is 37 years old.
Researchers discovered that the BRCA2 mutation did not to have an effect on a woman’s AMH concentration in either carriers or non-carriers, therefore causing no negative effects on fertility.
Mutations in the BRCA1 and BRCA2 genes are also associated with a higher risk for breast cancer, high grade serous ovarian cancer, fallopian tube cancer and primary peritoneal cancer.
Since BRCA2 has a less significant role in the repair of double-strand DNA, women with BRCA2 mutations are less likely to develop cancer at a later age. Women with BRCA1 mutations, on the other hand, are advised to consider having surgery to remove both ovaries and both fallopian tubes, once they are done having children and before they hit menopause. The earlier this procedure is done decreases the woman’s risk of breast cancer.
Researchers stated in their findings that while data suggests that ovarian reserve, and hence fertility, may be reduced in BRCA1 mutation carriers, they must conduct further research to fully understand the direct clinical implications of these ﬁndings.