Fibroids not encroaching the endometrial cavity and IVF success rate: a prospective study

BACKGROUND The impact of fibroids, not encroaching the endometrial cavity, have on the rate of success of IVF is still controversial. Recent meta-analyses suggest a detrimental effect of intramural lesions but not subserosal lesions. However, they also emphasize the need for further evidence. In order to elucidate this, we designed a prospective cohort study to compare the rate of success of IVF in women with and without fibroids. METHODS Exposed women were those with asymptomatic intramural or subserosal fibroids with a diameter below 50 mm and who were selected for IVF. Unexposed women were those free of fibroids, who were matched to cases by age and number of previous IVF cycles. All recruited patients underwent hystero-sonography to rule out intra-cavitary lesions. RESULTS There were 119 cases and 119 controls recruited. The number of clinical pregnancies in women with and without fibroids was 28 (24%) and 22 (19%), respectively (P= 0.43). The adjusted odds ratio (OR) for pregnancy in affected women was 1.38 [95% confidence interval (CI): 0.73-2.60]. The number of deliveries was 22 (18%) and 16 (13%), respectively (P= 0.38). The adjusted OR was 1.45 (95% CI: 0.71-2.94). Similar results emerged when focusing exclusively on women carrying intramural lesions (n= 80 couples). There was no significant relationship between clinical outcome and either the number or size of the fibroids. CONCLUSIONS In asymptomatic patients selected for IVF, small fibroids not encroaching the endometrial cavity did not impact on the rate of success of the procedure.