Jet lag reduces fertility in mice

Changes in the light-dark cycles reduce the number of pregnancies in female mice, according to a study published in the journal PLoS ONE . The study shows that disruptions in the normal circadian rhythm have consequences on fertility in mammals and could explain some of the reproductive health disorders seen in female airline workers.

The researchers, from Northwestern University (Illinois, USA), subjected female mice to alterations in the light cycle, either advancing it by 6 hours or delaying it, and maintained another group of females with a normal cycle of 12 hours light and 12 dark. The results revealed that, while in females with normal cycles 90 percent of intercourse generated pregnancies , in those subjected to delayed cycles the success was only 50 percent, and in advanced cycles this number fell to 22 percent.

Alterations in the menstrual cycle and spontaneous abortions are registered in many airline workers. This study reinforces the idea that these imbalances could be due to alterations in the light-dark cycle.