By considering the exclusion and inclusion criterias, 112 tubal ligated (case) and 288 non-tubal ligated subjects (control) were evaluated for menstrual abnormalities. Of 112 subjects in the case group, 57 (50.8%) had menstrual abnormalities. The corresponding figure in the control group was 143, accounting for 49.6% of the studied subjects in this group. The results of chi-square analysis, indicate that there was no significant difference in the menstrual abnormalities between two groups, χ2 = 0.050, p = 0.824.
The highest frequency of the menstrual abnormalities in the case group was 54.3% for the group aged between 30–39 while in the control group this value was 65% for those aged 40–45. There was significant difference in the menstrual abnormalities frequency of two groups by different age groups, χ2 = 9.06, p = 0.0176 (Table ).
Demographic and obstetrical information of subjects with menstrual irregularities in case and control groups
Type of abnormal bleeding is given in Figure . The most common type of menstrual changes in case and control groups was polymenorrhea (35%) and menorrhagy (30%) respectively. The differences were not significant, χ2 = 6.93 p = 0.2260.
Comparison of the menstrual irregularities type of case and control groups
The frequency onset of abnormal bleeding after sterilization in the case group was 61% during the first year, 34% in 2–5 years after sterilization and 5% over 5 years.
The menstrual abnormality frequency distributions by different parity groups in the case and control groups are shown in Table . The most common menstrual abnormalities frequency which belonged to parity of 5–7, was 50% and 40% in case and control groups respectively. The parity differences between two groups were not significant, χ2 = 1.93 p = 0.3819.
The most common histologic findings in case and control groups were proliferative endometrium 31.6% and anovulatory cycle (28.7%) respectively. There was no significant difference in the histologic finding of two groups, χ2 = 5.351, p = 0.253.