Labor ward workload waxes and wanes with the lunar cycle, myth or reality?

Objective: To test the validity of the statement "We are busy because it is getting close to the full moon" often heard on labor ward, by analysis of birth statistics in relation to lunar cycles.Method: Data for births from spontaneous onset labors for 12 lunar cycles from January 1 to December 31, 1994 was analyzed. Births resulting from induced labors were excluded. Birthrate for each day of the lunar cycle from new moon to full moon (ascending lunar phase) and from full moon to new moon (descending lunar phase) were analyzed using Pearson correlation coefficient. Birthrate at full moon was compared to that at new moon and that at mid ascending lunar phase was compared with that at mid descending lunar phase using t test.Results: There were 3706 spontaneous births during the study period. The average daily birthrate was 10.58 with standard deviation (SD) of 1.27. There was no statistically significant difference in the daily birthrate between the ascending and the descending lunar phases, r = -0.21. Statistical analysis showed no significant difference in the number of births at full moon as compared to that at new moon, P =.44. No difference was found on comparison of number of births during the mid ascending phase to that at the mid descending lunar phase, P =.84.Conclusion: Scientific analysis of data does not support the belief that the number of births increases as the full moon approaches, therefore it is a myth not reality.