Table 4.

Timing of prenatal infection and risk of schizophrenia and other psychotic disorders in adult offspring

Time of exposure	Infectious agent	Effect sizea	Study	Cohort
Around conception	Genital/reproductive infection	5	Babulas et al. 2006	PDS
First trimester	Influenza	7	Brown et al. 2004a	PDS
	Bacterial infection	2	Sorensen et al. 2009	Copenhagen  perinatal cohort
Second trimester	Influenzab	3	Brown et al. 2004a	PDS
	Respiratory infection	2	Brown et al. 2000
Third trimester or at delivery	HSV-2	1.5	Buka et al. 2001, 2008  and Xiao et al. 2009	NCPP
	Toxoplasma gondii	2	Brown et al. 2005	PDS
			Mortensen et al. 2007, 2010	Danish cohorts

NCPP, National Collaborative Perinatal Project ; PDS, Prenatal Determinants of Schizophrenia ; HSV-2, herpes simplex virus type 2.

^aOnly studies that reported an increase in risk in relation to prenatal infection were included in this table ; approximate point estimates shown for guide purpose only ; heterogeneity in exposure measurement, case definition, analysis and measure of risk exists between individual studies, refer to Table 1 for individual study details and results.

^bEarly second-trimester exposure.