The prevalence of adenomyosis in an infertile population: a cross-sectional study

RESEARCH QUESTION: Adenomyosis has been reported in a high proportion (24.4%) of infertile women, but this may be over-representative. What is the exact prevalence of adenomyosis in an infertility clinic population? DESIGN: In this cross-sectional study, 320 infertile women ≤41 years of age attending the infertility clinic of a university teaching hospital were screened by two-dimensional transvaginal ultrasound (2D-TVS) to look for the sonographic markers of adenomyosis, with subsequent magnetic resonance imaging (MRI) if suspected. Additionally, the adenomyosis subtype (I-IV) was determined from MRI geography (Kishi classification). Comparisons between women with and without adenomyosis were carried out. RESULTS: Adenomyosis was found by 2D-TVS in 24 cases (7.5%) and confirmed by MRI in 21 (6.6%). The mean age of the group was 29.2 ± 4.7 years. The most frequently observed sonographic finding (58.3% of cases) was asymmetrical myometrial thickening. The majority of MRI-confirmed cases (85.7%) had diffuse adenomyosis. A significantly higher prevalence was found in women ≥40 compared with women <40 years old (40.0% versus 4.9%, respectively; P < 0.0001). Adenomyotic women had significantly higher mean age (32.7 ± 3.0 versus 28.6 ± 4.4 years; P < 0.00001), body mass index (31.3 ± 2.7 versus 28.7 ± 3.3 kg/m2; P < 0.0001), suffered more dysmenorrhoea (38% versus 17%; P = 0.02) and had more ovarian endometriomas (19% versus 6%; P = 0.03) than those without adenomyosis. CONCLUSION: The observed prevalence of adenomyosis detected de novo by 2D-TVS in a population of young infertile women (7.5%) should alert gynaecologists and ultrasonographers to look for the features of adenomyosis when scanning such patients.