The Lunar Cycle and the Number of Deliveries in Austria between 1970 and 1999

The effect of the moon on the number of newborns has been investigated extensively with contradictory results but with few significant findings. In this paper, a possible lunar effect is analyzed by a nonlinear Poisson regression model similar to a Fourier analysis based on all children (n = 2,760,362) born in Austria between 1970 and 1999, i.e. 371 lunar cycles. We found no significant effect even when considering the influence of parity and gestation. Our study is in contrast to a French study using a similarly large data base which showed a weak but significant effect. Nevertheless, significant p values based on very large samples must be interpreted cautiously. Our study is in concordance with other studies which often use small and selected samples or rather inefficient statistical methods. We conclude that there is no significant effect of the lunar cycle on the number of deliveries in Austria.