A recent study found that lower vitamin D levels were associated with irregular menstrual cycles, but not with short or long cycles.
Most women have menstrual periods occur every 28 days, lasting four to seven days. However, some women experience abnormal menstruation. Examples of irregular menstrual cycles include periods that last more than seven days, periods that occur less than 21 days or more than 35 days apart, and missing more than three periods in a row.
Animal studies have found an association between low vitamin D status and menstrual cycle disturbances. However, no research had studied humans.
Researchers recently examined the association between vitamin D levels and menstrual cycle characteristics. They gathered information of 636 women between the ages of 35 and 44 from Washington D.C. The study was titled the Uterine Fibroid Study.
All women provided a blood sample and completed a telephone interview, where they were asked about their menstrual cycle.
The average vitamin D level was 12.0 ng/ml. After adjusting for potential confounding factors, a decrease of 10 ng/ml in vitamin D status was associated with 1.9 times the odds of irregular cycles. Though, vitamin D status was not associated with short or long cycles.