Uterine fibroids are tumors that arise within the wall of the uterus. They are the most common non-cancerous tumors in women of childbearing age. Uterine fibroids can cause pain and abnormal bleeding. Although uterine fibroids can make it difficult for a woman to get pregnant or maintain a pregnancy, scientists do not fully understand exactly how fibroids affect fertility.
A set of genes known as the tuberous sclerosis complex (TSC) can cause noncancerous tumors like fibroids to grow. To determine whether TSC genes were involved in infertility related to fibroids, scientists funded by the Fertility and infertility Branch used a mouse model of TSC. They compared normal mice with mice lacking TSC and looked for differences throughout the reproductive system.
The scientists found that TSC was involved in several parts of different reproductive processes. For example, in mice without the TSC genes, many egg cells did not mature properly. Egg cells that did mature correctly were able to be fertilized, but they could not exit the fallopian tube to enter the uterus for implantation. The results from this study indicate that any disruption to the function of TSC could likely lead to infertility (PMID: 22128018).