The chief basis for fibroid tumors affecting fertility is location, location, location. Submucosal fibroids (located in the endometrial cavity of the uterus) have been shown to cause the greatest problems with conceiving and also have the strongest association with reduced rates in maintaining a pregnancy. Studies suggest that sub-mucosal fibroids create problems with the implantation of the pregnancy in the uterine cavity, as well as with the location and development of the placenta.
One study showed a 70% decrease in the pregnancy rate of women with submucosal fibroids. Most fertility specialists have been recommending the surgical removal of submucosal fibroids before attempting assisted reproductive techniques such as in vitro fertilization (IVF). Intramural and subserosal fibroids may adversely affect a woman’s ability to become pregnant if they are located near enough to where the fallopian tubes attach to the uterus that they cause an occlusion or blockage of the tubes.