Association between serum ۲۵-hydroxy vitamin D level and menstrual cycle length and regularity: A cross-sectional observational study

Background: Research examining the role of vitamin D deficiency and the development of menstrual disorders in women is of widespread interest. Studies have been published showing that supplementation with high-dose vitamin D can lead to the restoration of the menstrual cycle. We lack adequate information regarding the effect of vitamin D levels on the physiology of menstruation and further on fertility in women of reproductive age due to the contradictory results reported by studies. Objective: To study the association of ۲۵-hydroxy vitamin D with menstrual cycle characteristics including long and short cycle length and cycle irregularity. Materials and Methods: In this cross-sectional study, serum vitamin D level of ۱۶۶ women attending an outpatient department with menstrual irregularities after excluding all obvious causes of menstrual disorders (n = ۸۳) between April-June ۲۰۱۹ were measured and were compared with women of similar profiles with complaints other than menstrual irregularities (n = ۸۳). Results: A decreased level of vitamin D was associated with a ۱۳.۳ times odds of an irregular cycle (OR (۹۵% CI): ۱۳.۳۰ (۵.۷۹-۳۰.۶۰), p < ۰.۰۰۱). ۲۵-hydroxy vitamin D was not associated with age or body mass index. We found a significant difference (p < ۰.۰۰۱) in mean vitamin D levels among the females with irregular cycles vs. regular cycles. Conclusion: Vitamin D plays a role in the physiology of reproduction specific to the menstrual cycle and ovulation. Long-term prospective studies assessing the exact cutoff value and the exact dose of supplementation required are needed.

Keywords:

Menstrual disturbances , Ovulation , Reproductive period , Vitamin D deficiency , Dietary supplements , Polycystic ovarian syndrome. , اختلالات قاعدگی , تخمک­گذاری , دوره باروری , کمبود ویتامینD , مکمل­های غذایی , سندرم تخمدان پلی­کیستیک.