Menstrual cycle length may be predictor for ovarian aging
Menstrual cycle length may be an accurate predictor of ovarian aging due to its association with ovarian reserve test values and fecundability rates, according to a systemic review published in Human Reproduction Update.
“Short menstrual cycle length in regularly cycling women seems to be associated with low ovarian reserve in the reproductive years,” Johnny S. Younis, MD, vice dean for clinical studies in the Azrieli Faculty of Medicine at Bar-Ilan University, Israel, told Healio. “Young women with short menstrual cycle length seem to have lower ovarian reserve tests values, reduced fecundability in natural cycles and inferior IVF outcome measures.”
Researchers searched an electronic database of research articles examining the association between menstrual cycle length and ovarian reserve in women of reproductive age, published from 1978 to August 2019. A systemic review and meta-analysis were done on 11 prospective and retrospective studies that presented anti-Müllerian hormone level, antral follicle count, IVF and fecundability rates as outcomes. Short menstrual cycles were categorized as 21 to 27 days, normal cycles were 28 to 31 days, and long cycles were 32 to 35 days. The “all-others” category combined normal and long cycles.
Four studies evaluated the association between menstrual cycle length and ovarian reserve tests. Two of those studies included both anti-Müllerian hormone level and antral follicle count as outcomes, one examined only anti-Müllerian hormone levels, and one looked at only antral follicle count. In the meta-analysis, serum anti-Müllerian hormone levels were lower in women with short menstrual cycles compared with those with normal cycle lengths (weighted mean difference, –1.3 ng/mL; 95% CI, –1.75 to –0.86; P < .001). Antral follicle count was also significantly lower in women with short menstrual cycles compared with those in the normal cycle group (weighted mean difference, –5.17; 95% CI, –5.96 to –4.37; P < .001).
Four studies measured fecundability rates in natural menstrual cycles. Compared with women with a normal menstrual cycle, those with a short cycle had a lower likelihood of conception (OR = 0.81; 95% CI, 0.72-0.91; P < .001). Data comparing the short vs. long menstrual cycle cohorts were not significant.
Three of five studies analyzing the association between menstrual cycle length and IVF data on the number of retrieved oocytes per treatment cycle. Women with a short menstrual cycle had a lower number of retrieved oocytes than the normal menstrual cycle (weighted mean difference, –1.8 oocytes; 95% CI, –2.5 to –1.1; P < .001) and long menstrual cycle groups (weighted mean difference, –4.2 oocytes; 95% CI, –6.5 to –2; P < .001).
Three studies included data on clinical pregnancy rates per IVF treatment cycle. Women with a short menstrual cycle were less likely to be pregnant per treatment cycle compared with those in all-other groups (OR = 0.76; 95% CI, 0.6-0.96; P = .02).
“What we found surprising was that short menstrual cycle length was not only associated with the quantitative facets of the ovarian reserve — ovarian reserve test values and number of oocytes in IVF — but as well with the qualitative aspects of ovarian reserve — fecundability in natural cycles and clinical pregnancy rate in IVF,” Younis said. “Educational efforts may guide women with short menstrual cycle length to seek professional counselling for substantiating the diagnosis of low ovarian reserve and discuss early pregnancy achievement or fertility preservation.”
Younis said these novel implications should be further examined in prospective, well-designed targeted studies.
For more information:
Johnny S. Younis, MD, can be reached at JYounis@poria.health.gov.il.
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