[Seasonal, weekly and lunar cycles of birth. Statistical study of 12,035,680 births]

The authors have studied the seasonal, weekly and lunar rhythms which could characterize deliveries, based on 12,035,680 french births, between January 1, 1968 and December 31, 1982. The seasonal rhythm is the most remarkable. It is characterized by a maximum of newborn in May and a minimum in November; there is an increased number of births during the month of September. The weekly rhythm is characterized by a drop in the number of births especially on Sundays, but also on Saturdays, with a maximum on Tuesday. The number of births also fluctuate according to the lunar cycle. Their amplitude is low. They are however significant. From that standpoint, these results confirm other studies already conducted in France and the USA, in a much smaller scale.