Which fibroid location is most likely to impair implantation?

• A. Subserosal fibroids
• B. Large intramural fibroids
• C. Submucosal fibroids
• D. Fibroids do not affect implantation equally

Answer: (C)

Submucosal fibroids directly intrude into the uterine cavity, where implantation occurs on the endometrium. Their growth distorts the cavity’s shape, disrupts the endometrial lining, and can alter the local blood flow and receptivity, all of which hinder embryo apposition and invasion. Because implantation depends on a smooth, functional endometrial surface, anything projecting into or distorting that cavity most reliably compromises the embryo’s ability to implant. By contrast, fibroids on the outside of the uterus (subserosal) or those entirely within the myometrium (intramural) usually spare the endometrial surface, unless they are large enough to distort the cavity, making submucosal locations the most likely to impair implantation.