Abstract
A hypothesis is proposed to explain the seasonality of births and its variations, that some unrecognized epidemic infertile factors have existed seasonally. In that case, certain women born in a particular low birth rate season must be those who survived these infertile factors in very early stage of their fetal lives. Then in later years, when they become pregnant, they may possibly be immune or different in their susceptibility to these infertile factors. Therefore, mothers born in a particular low birth rate season would tend to bear babies more frequently in that season than the others. To examine this hypothesis, birth records in 1930 of two maternity hospitals in Tokyo were investigated. These years were chosen for a period when seasonality of birth was most prominent in Japan. First babies were excluded to eliminate disturbances by season of marriages and other possible non-biological factors. The results show that among 1038 mothers born in a low birthrate season, May–July, 245 (23.6%) had babies in May–July, while the other mothers had significantly less babies (19.0%, 819/4302, P<0.001) in the same season. This may imply that seasonality of birth may have been influenced by some immunogenic infertile factors epidemic in a particular season.
Similar content being viewed by others
References
COHEN, I. C. and BRACKEN, M. B. (1977): Monthly variation in conceptions leading to induced abortion. Social Biol., 24: 245–250.
DOOSONO, S. (1944): Statistical observations on month of human conceptions. Minzoku Eisei (Tokyo), 12: 79–86.
ERHARDT, C. L., NELSON, F. G. and PARKER, J. (1971): Seasonal patterns of conception in New York City. Amer. J. Pub. Hlth., 61: 2246–2258.
MIURA, T., TAMURA, M., SHIMURA, M. and OGATA, T. (1976): The influence of the season of birth on preventive efficacy of the Japanese encephalitis vaccine. Jap. J. Hyg., 31: 520–524.
MIURA, T., OGATA, T. and EMA, M. (1977): An epidemiological study on the susceptibility of Japanese people to Japanese encephalitis virus infection by season of birth. Jap. J. Hyg., 32: 429–433.
MIURA, T. and SHIMURA, M. (1978): Secular changes of fertility by season of mothers' births. Minzoku Eisei (Tokyo), 44: (Suppl.) 118–119.
MIURA, T. SHIMURA, M. and NNAKAMURA, I. (1979): Jahreszeitliche Schwankungen von Menarche und Geburtsmonat in Japan. Ärztl. Jugendk., 79: 37–40.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Miura, T., Shimura, M. Epidemic seasonal infertility — a hypothesis for the cause of seasonal variation of births. Int J Biometeorol 24, 91–95 (1980). https://doi.org/10.1007/BF02245548
Issue Date:
DOI: https://doi.org/10.1007/BF02245548