Long distance air travel can send your menstrual cycle off course. “Travelling through time zones can disrupt your body’s circadian rhythm,” says Dr. Prati Sharma, a reproductive endocrinologist at the Create Fertility Centre, and an associate physician at Sunnybrook and Women’s College Hospitals in Toronto. Your circadian rhythm is responsible for your sleep-wake cycles, and the release of hormones. It typically follows a 24-hour cycle and responds to light and darkness in your environment. Flying across time zones can upset the circadian rhythm and by proxy your menstrual rhythm. “This disruption is due to an alteration in two hormones – cortisol (the stress hormone) and melatonin (a hormone that’s affected by exposure to light),” says Dr. Sharma. “There’s lots of data that suggests that flight attendants have menstrual irregularity – longer or shorter cycles.”
Most women who take a single 6-hour flight won’t notice any differences, but women who fly frequently between Europe and North America could be affected.
Women who have chronic insomnia or jobs that include overnight shifts could also experience menstruation disturbances as a result of a lack of light exposure and changes in their circadian rhythm.