Myomas and Adenomyosis: Impact on Reproductive Outcome

Abstract

Among uterine structural abnormalities, myomas and adenomyosis represent two distinct, though frequently coexistent entities, with a remarkable prevalence in women of reproductive age. Various mechanisms have been proposed to explain the impact of each of them on reproductive outcome. In respect to myomas, current evidence implies that submucosal ones have an adverse effect on conception and early pregnancy. A similar effect yet is not quite clear and has been suggested for intramural myomas. Still, it seems reasonable that intramural myomas greater than 4 cm in diameter may negatively impair reproductive outcome. On the contrary, subserosal myomas do not seem to have a significant impact, if any, on reproduction. The presence of submucosal and/or large intramural myomas has also been linked to adverse pregnancy outcomes. In particular increased risk for miscarriage, fetal malpresentation, placenta previa, preterm birth, placenta abruption, postpartum hemorrhage, and cesarean section has been reported. With regard to adenomyosis, besides the tentative coexistence of adenomyosis and infertility, to date a causal relationship among these conditions has not been fully confirmed. Preterm birth and preterm premature rupture of membranes, uterine rupture, postpartum hemorrhage due to uterine atony, and ectopic pregnancy have all been reported in association with adenomyosis. Further research on the impact of adenomyosis on reproductive outcome is welcome.

Figure 1

FIGO classification of myomas. FIGO classification system of myomas introduced by Munro and colleagues in 2011 [31] is based on the relationship of the fibroid with the uterine wall. According to this classification, type 0 to type 8, the last one representing fibroids, which cannot otherwise be classified, have been proposed, whereas for a subset of fibroids, two numbers may be applicable, the first one referring to the relationship with the endometrium and the second one with the perimetrium. This possibility can indirectly imply the size of a myoma, which, for instance, extends throughout the uterine wall protruding into the uterine cavity and concurrently distorts the outline of the uterus (type 2–5). Type 0: pedunculated intracavitary. Type 1 submucosal < 50% intramural. Type 2: submucosal ≥ 50% intramural. Type 3: entirely intramural, contacting the endometrium. Type 5: subserosal ≥ 50% intramural. Type 6: subserosal < 50% intramural. Type 7: subserosal pedunculated. Type 8 (not shown in the figure): others, that is, cervical, originating from the round ligament or parasitic.