Age at Menarche, Duration of Monthly Flow and Cycle Length as Risk Factors for Endometriosis in Sub-Sahara Black African Women

Abstract

Introduction: Endometriosis is an enigmatic and multifaceted ailment that distresses a large number of women worldwide which may trigger pain, infertility and other discomforts such as dysmenorrhea. Materials and Methods: Data from the medical records of 113 women with and 113 age-matched women without endometriosis were analyzed retrospectively to investigate association of three domains of menstrual characteristics – age at menarche, duration of menstrual flow and cycle length – with risk of developing endometriosis. STATA 13 statistical software was used for analysis of data. Results: Sub-fertile women with menarche at <11 years were 1.80 times more likely to have endometriosis (OR=1.80, 95% CI: 0.51, 6.33) and had 1.29 times the risk of the disease (RR=1.29, 95% CI: 0.81, 2.06) influenced by body mass index (BMI in Kg/m2 ). Women with duration of flow of 4-7 days were 2.33 times more likely to have endometriosis. Women with cycle length of ≥28 days were 1.45 times more likely to also have endometriosis. Mean egg yield at OPU from endometriotic women was significantly lower than that from women without endometriosis when age at menarche was ≥14 years (t-test=-4.44, P-value=0.00000001), when duration of flow (days) was 4-7 (t-test=-4.78, P-value=0.00000001) and when cycle length was ≥28 days (t-test=-4.35, P-value=0.00000001). The mean matured eggs (MII) was very significantly higher when age at menarche was ≥14 years (t-test=-2.59, P-value=0.006), when duration of flow was 4-7 days (t-test=2.81, P-value=0.003) and when the cycle length was ≥28 days (t-test=-2.79, P-value=0.003). Multivariate regression analysis indicated that menarche, number of days of menstrual flow and cycle length gave a significant 90% of the variation found in endometriosis (R2=0.9001, F=648.77, P-value=0.000000001). Conclusion: Menarche at age <11 years and cycle length of ≥28 days were significantly associated with and were better predictors of laparoscopic ally confirmed endometriosis. BMI influenced all of the three domains of menarche, duration of flow (days) and cycle length. Endometriotic women produced fewer oocytes but fertilization rate was not compromised.