Seasonal onset of the menopause.

A seasonal rhythm of reproduction is evident in humans. Herein it was investigated whether also the cessation of woman's fertile life follows a seasonal rhythm.A retrospective study was performed on 2436 women in postmenopause for more than 12 months, in our menopause centres. Time of menopause was stratified for month and season. The variation was compared to the seasonal rhythm of 14,310 conceptions.The onset of menopause was more frequent (p<0.0001) in winter (32.5%) than in spring (20.8%), autumn (20.3%) and summer (26.2%), in which a minor peak was also observed (p<0.0001 vs. spring and autumn). The two peaks were temporally coincident with the transitions between the high to low and low to high rate of conceptions.The present data show that in women, like reproduction also the onset of menopause shows a seasonal modulation.