Prenatal Infections

For over 200 years it has been conjectured that prenatal infection results in adverse physical and developmental outcomes for children. In 1787 William Perfect wondered whether a particularly virulent influenza epidemic occurring during that year was responsible for an increase in insanity among those gestationally exposed. In 1845 Esquirol commented that insanity is more prevalent during epidemic years and this increase seems to be independent of moral causes. At the turn of the 20th Century Emil Kraeplin (1919) commented that “infections in the years of development might have a causal significance” for dementia praecox (p. 240). After the 1919 influenza pandemic, which killed more people than World War I, Karl Menninger speculated that the infection may be causally related to schizophrenia. Menninger (1928) later retracted his statement.

In 1941 Sir Norman Gregg, an Australian pediatric ophthalmologist, discovered that mothers who contracted rubella during pregnancy had offspring with severe eye cataracts and other physical deformities. Gregg (1941) reported that of the 78 children born in the first few months of 1941 who came to see a doctor in the Sydney area for cataracts, 68 had been prenatally exposed to Rubella, two to three times the usual congenital rate. This research increased professional interest in the relationship between viral infections, and profound physical and neurological outcomes that were clearly evident at birth.

It was not until 1988 when researchers turned their gaze toward prenatal infection in relation to more subtle psychological and behavioral outcomes. This interest was inaugurated following Mednick, Machon, Huttunen and Bonnett’s (1988) reported association between the 1957 influenza pandemic and increased risk of schizophrenia in a sample from Finland. Since this study, more than three dozen articles have appeared that have investigated this issue. The majority have found a significant association between infection and schizophrenia. Since the early 1970s other prenatal infections including Rubella, measles, mumps, cytomegalovirus, chicken pox, toxoplasmosis and herpes simplex 2 have been sporadically investigated for their possible association with psychopathology. The research base on these infections in relation to psychological and behavioral outcomes is sparse compared to that of influenza.

Within this chapter we broadly review the extant literature regarding some of the more commonly experienced prenatal infections in relation to adverse developmental outcomes. We have further limited the discussion primarily to psychological and behavioral effects.