CONGENITAL DISLOCATION OF THE HIP (CDH) AND SEASONALITY: THE GESTATIONAL AGE OF VULNERABILITY TO SOME SEASONAL FACTOR

Chen, R., S. L Weissman, R. Salama and M. A. Klingberg (Dept. Epidemiology, Israel Institute for Biological Research, Ness-Ziona, Box 19, Israel). Congenital dislocation of the hip (CDH) and seasonality: the gestational age of vul nerability to some seasonal factor. Amer. J. Epid., 1970, 92: 287–293.—The Ortolani test was used as a tool of diagnosis of CDH among 30, 956 newborns dur ing 1962–1967 in Haldria Hospital, Tel Aviv. The phenomenon of seasonal fluctu ations of positive Ortolani cases was studied. A significantly higher rate among infants bom during cold months as compared to the rate among infants born ir the warm season was encountered. A hypothesis concerning the gestational age a which the fetus is susceptible to the unknown seasonal factor was formulated of the bash of two sets of data—both collected in Israel (one in Tel Aviv by the authors, and the other in West Jerusalem by Medalie et al., Israel J. Med. Sci., 1966 2: 212–217). The age in question seems to be the fourth and fifth month, and possi bly the sixth month.