Teratogenic effects of Asian influenza.

That a cause and effect relationship exists between a maternal viral infection during the first trimester of pregnancy and congenital defects in the child remains inconclusive, except in rubella, since most of the studies are of a retrospective type. Introduction of Asian influenza into our population afforded conditions for study of this possible relationship with a greater measure of control and more factors known prior to birth of the infants.In March, April, and May of 1958, hemagglutination-inhibition titers for Asian influenza were determined on 126 expectant mothers whose last menstrual periods occurred in October, November, and December of 1957. Mothers (75) having positive titers were considered to have had influenza and were compared with those (51) having negative results. The two groups of mothers did not differ significantly with respect to the incidence of anomalies among the children delivered, and no definite evidence of a teratogenic effect of Asian influenza virus was found.