Conclusions

The plots show no convincing peak or sinusoidal variation in phase with either the lunar phases or varying distance due to the Moon's orbit. The scatter may be larger than what would be expect due to sampling a random variation but some systematic effects are not taken into account here. Those include the weekly and annual cycles as well as significant drops in births at the major holidays. Our earlier work which suggested a sinusoidal variation with a peak near third quarter was probably a random anomaly for that time period with statistically insignificant variations.

These results agree with current work on French births being studied by Chambat (2001/2), whose current working plot for 14.5 million births is shown below.