Birth rate and its correlation with the lunar cycle and specific atmospheric conditions

Abstract

Objective: This study was undertaken to use the Arizona State birth certificate database for Phoenix metropolitan hospitals, in conjunction with National Weather Service records to determine whether there is a relationship between birth rate and meteorologic or lunar conditions. This study attempts to dispel or lend significance to beliefs among hospital staff that the phase of the moon and/or meteorologic conditions are related to birth rate. Study design: Birth records were limited to spontaneous vaginal deliveries, 37 to 40 weeks' gestation, in Phoenix, between 1995 and 2000 (n = 167,956). Daily birth counts were merged with daily surface weather statistics from the National Weather Service for Sky Harbor Airport, and records of lunar phase for the same period. Results: The analyses revealed no significant correlates of birth rate. Conclusion: Although there exists a popular belief that the phase of the lunar cycle and weather conditions affect birth rate, no such evidence was found in this study. © 2005 Elsevier Inc. All rights reserved.