Circadian rhythm and its disruption Impact on reproductive function

The three articles in this month’s “Views and Reviews” section discuss the impact of circadian rhythms, especially the nocturnal secretion of melatonin, on reproductive function and parturition in the human.

Robert F. Casper, M.D., Bojana Gladanac, M.Sc.

Volume 102, Issue 2, Pages 319–320


Almost all forms of life have predictable daily or circadian rhythms in molecular, endocrine, and behavioral functions. In mammals, a central pacemaker located in the suprachiasmatic nuclei coordinates the timing of these rhythms. Daily light exposure that affects the retina of the eye directly influences this area, which is required to align endogenous processes to the appropriate time of day. The present “Views and Reviews” articles discuss the influence of circadian rhythms, especially nightly secretion of melatonin, on reproductive function and parturition. In addition, an examination is made of problems that arise from recurrent circadian rhythm disruption associated with changes in light exposure patterns common to modern day society. Finally, a possible solution to prevent disruptions in circadian phase markers by filtering out short wavelengths from nocturnal light is reviewed.

  • Jason Kovac

    The seasonal contribution to testosterone fluctuations has also been proposed and, as recently reviewed by Smith et al., seasonal variations were found not to affect male hormone testosterone levels. Would be interesting to see how couples would fair when combined together. Measuring both members of the couple for testosterone and melatonin to determine whether together, these fluctuations are related.

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