Many species synchronise their reproductive behaviour with a particular phase of the lunar cycle to increase reproductive success. The human menstrual cycle also has a period close to that of the lunar cycle, but an influence of the moon on reproductive behaviour remains controversial. In a previous study, we showed that the menstrual cycles of younger women (age >35 years) coincided at times with the lunar luminosity and/or gravimetric cycles. The data used in that study was mostly recorded before the year 2000. Now we repeated our study with the menstrual cycles of young women from the year 2000 onwards. We found that significant synchronisation with the lunar cycles had been lost throughout the year. However, significant synchronisation with the lunar cycles remained during the winter months when the Earth is closest to the Sun and the gravimetric forces of the Moon and Sun on the Earth add up. Combining the old and new data, we found that the temporary synchronisation with the luminosity cycles of the Moon was lost from 2010 onwards, coinciding with the time when high-energy blue LEDs replaced other light sources and light pollution on Earth increased significantly. We hypothesise that human reproductive behaviour used to be synchronised with the Moon, but that our modern lifestyle and increasing artificial night-time light have changed reproductive physiology. The biological relevance of the earlier synchronisation is discussed.