Menstruation, the oral contraceptive pill, and acute appendicitis.

OBJECTIVE: To find out if there was any association between histologically confirmed acute appendicitis, menstruation, and the use of the oral contraceptive pill. DESIGN: Retrospective study. SETTING: District general hospital, Scotland. SUBJECTS: 366 consecutive patients (median age 21, range 10-51) with histologically confirmed acute appendicitis during the period 1981-1990 were studied, 314 of whom were having menstrual cycles. 208 patients with physiological menstrual cycle were included in the study, and 82 patients were taking the oral contraceptive pill. INTERVENTIONS: Prospectively collected standardised data using computer assisted diagnosis of acute abdominal pain was used to review patients with histologically confirmed acute appendicitis. RESULTS: Acute appendicitis was confirmed in 17/208 of patients (8%) who were menstruating, which is significantly less than might be expected (p < 0.003). 5/82 (6%) of those taking oral contraception had withdrawal bleeding and acute appendicitis (p = 0.2). CONCLUSIONS: Acute appendicitis is less common among women during physiological menstruation, but no differences are noted during the withdrawal bleeding phase when taking oral contraception.