Irregular menstrual cycles

Age is associated with irregular menstrual cycles in humans (44.7% at ages 51-55 versus 28.3% at ages 36-40).

“The proportion of individuals with irregular cycles was highest in participants aged 51-55 (44.7%), and lowest in the 36-40 age group (28.3%).”

Humans

Chronicling menstrual cycle patterns across the reproductive lifespan with real-world data

Scientific reports·3 May 2024

Luteal out-of-phase events are associated with irregular menstrual cycles in humans.

“They were also associated with abnormally short (<21 d) or long (>40 d) cycle length.”

Humansin early and late menopausal transition

Atypical estradiol secretion and ovulation patterns caused by luteal out-of-phase (LOOP) events underlying irregular ovulatory menstrual cycles in the menopausal transition

Menopause (New York, N.Y.)·1 Jan 2009