Menstrual Cramps in Anovulatory versus Normally Ovulatory Cycles — SARS-COV-2 Pandemic Daily Data Plus a Meta-Analysis of Cramps and Anovulation

Abstract

Gurleen Mann,1 Sonia Shirin,2,3 Sewon Bann,2– 4 Paul J Yong,2,3,5 Dharani Kalidasan,2 Azita Goshtasebi,2,3 Jerilynn C Prior2– 4,6 1University of British Columbia, Vancouver, British Columbia, Canada; 2Centre for Menstrual Cycle and Ovulation Research, University of British Columbia, Vancouver, British Columbia, Canada; 3British Columbia Women’s Health Research Institute, Vancouver, British Columbia, Canada; 4Division of Endocrinology and Metabolism, Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada; 5Department of Obstetrics and Gynecology, University of British Columbia, Vancouver, British Columbia, Canada; 6School of Population and Public Health, University of British Columbia, Vancouver, British Columbia, CanadaCorrespondence: Jerilynn C Prior, Diamond Healthcare Centre – Division of Endocrinology and Metabolism, 2775 Laurel Street, Suite 4111, Vancouver, British Columbia, V5Z 1M9, Canada, Tel [phone], Email [email protected]: It is asserted that primary dysmenorrhea/menstrual cramps only occur in ovulatory menstrual cycles. Our first objective was to present detailed menstrual cramps information in normally ovulatory versus anovulatory cycles from a single-cycle cohort study during the SARS-CoV-2 Pandemic. Secondly, we reviewed the literature for cohort studies documenting both menstrual cramps and ovulation.Participants and Methods: The Menstruation and Ovulation Study 2 recruited 108 women ages 19– 35 years to a prospective, observational single-cycle study, recording cramps daily (0– 4 scale) in the Menstrual Cycle Diary© and assessing normal ovulation (luteal length ≥ 10 days) by the validated Quantitative Basal Temperature© (Mean Temperature Method). We searched databases for « primary dysmenorrhea » / » menstrual cramps »; « menstrual cycles »; « anovulation », finding four valid publications.Results: In 75 women/cycles during the Pandemic, mean age was 28.5, body mass index 23.5, and higher education (16 years); 40 normally ovulatory and 35 anovulatory cycles had similar lengths (29.5– 30.0 days), respectively (P= 0.571). However, anovulatory cycles recorded significantly worse menstrual cramps versus normally ovulatory cycles; anovulatory median intensity was 1.9 versus 1.6, and Cramp Score was 8 versus 6 in normally ovulatory cycles (P=0.017). Four publications in 273 women (991 cycles) showed cramps in both anovulatory and ovulatory cycles; three were in adolescent/young adult women, one of which documented a significantly greater percentage of cramps in ovulatory cycles. The 694 cycles in premenopausal women (20– 41 years) showed similar percentages of symptomatic cramps in cycles of both ovulatory types. Meta-analysis documented significantly higher cramp prevalence in ovulatory cycles (OR 2.10; 95% CI 1.31, 3.37; P=0.002).Conclusion: This is the first documentation of more intense and frequent cramps in anovulatory cycles. However, meta-analysis showing the presence of symptomatic cramps in both ovulatory and anovulatory cycles documented they were twice as prevalent in ovulatory menstrual cycles.Plain Language Summary: “Worse Menstrual Cramps in Anovulatory Cycles”. Medicine has long believed that menstrual cramps only occur in ovulatory menstrual cycles that release an egg and have high progesterone levels that decrease before the next period. The notion was that dropping progesterone levels triggered release of prostaglandins that cause the pain and uterus muscle contractions of menstrual cramps. This research studied 75 community women aged 19– 35 years for a single cycle during COVID-19. Forty women had normally ovulatory cycles and 35 had anovulatory cycles with a similar mean cycle length of 29.7 days. Women in both groups were similar in age, weight, education and other reproductive characteristics. Women recorded Menstrual Cycle Diary© daily experiences for cramp presence and intensity (scored 0– 4). Ovulation was documented by daily first morning temperatures analyzed by the valid Quantitative Basal Temperature© method. Results showed menstrual cramps occurred in both normally ovulatory and anovulatory cycles. Surprisingly, anovulatory compared with ovulatory cycles had cramps that lasted longer (4 rather than 3 days), were more intense (1.9 versus 1.6) and with significantly higher Cramp Scores (of 8 versus 6). We also found four other published studies showing cramps occurred in both anovulatory and ovulatory cycles. A meta-analysis of these, however, showed that cramps were twice as frequent in ovulatory cycles. These results matter because they stimulate the search for more accurate understandings of why menstrual cramps occur. They will likely stimulate more effective therapies for the rare, intense menstrual cramps that currently are not effectively treated by anti-inflammatory medicines such as ibuprofen.Keywords: primary dysmenorrhea, menstrual pain, menstrual cycles, ovulation, adolescent, premenopause

Keywords

• primary dysmenorrhea
• menstrual pain
• menstrual cycles
• ovulation
• adolescent
• premenopause.