Endometrial tissue builds up during the menstrual cycle, and then breaks down and sheds off during a period.

BBC: NEWS | Health | A life plagued by painful periods

Her chosen poison was oestrogen, one of the hormones that make women women and help to control the menstrual cycle.

ECONOMIST: Human contraceptives are bad for fish

He said his studies with co-worker Craig Roberts showed female attractiveness also fluctuated throughout the menstrual cycle, peaking at a woman's most fertile days.

BBC: NEWS | Health | 'Hormonal' women most attractive

They also found "pronounced" symptom variations during the menstrual cycle in women with asthma, and say the findings suggest women might need tailored medication regimes.

BBC: Hormones in menstrual cycle 'affect asthma'

Researchers will study whether inserting the Pap brush deeper, testing during different times of the menstrual cycle, or other factors might improve detection of ovarian cancer.

NPR: Retooling Pap Test To Spot More Kinds Of Cancer

Christine Hitchcock, who works at the Centre for Menstrual Cycle and Ovulatory Research at the University of British Columbia, in Vancouver, worries that there is not enough research to show the long-term effects of the extended use of oral contraceptives on the breast.

ECONOMIST: Controlling menstruation

The longer a woman has her menstrual cycle, the greater the risk of getting breast cancer, medical experts said.

CNN: Tweens challenged by grown-up malady: Breast cancer

That paper also found that male sweat may affect the length and timing of a woman's menstrual cycle.

CNN: Sweat may give off stress signals, study says

The hormones in the spray replace the small amount of testosterone produced by the ovaries and are equal to the smallest amount of oestrogen produced by a woman during her menstrual cycle.

BBC: Hormone spray 'could stop cancer'

Those who were ovulating rated the "dominant" men as sexiest, but there was no similar pattern among women at other stages of their menstrual cycle.

BBC: NEWS | Health | Woman's scent can lure or repel