Uterine fibroids are the most common uterine tumours, and are increasingly being detected in pregnancy. Depending on the location and size of the fibroid, it may have significant maternal and fetal consequences, both antenatally and postnatally. The paucity of evidence based management presents a diagnostic and management dilemma when clinicians are faced with large uterine fibroids in pregnancy. We report a rare case of a large subserosal uterine fibroid in pregnancy in a primiparous woman causing significant mass effect, and describe diagnosis, management and maternal and fetal outcomes.