A prospective cohort study that lasted 60 years was published late 2019 in The American Journal of Psychiatry, it reports that maternal bacterial infection and other prenatal immune challenges significantly increased the risk of schizophrenia and related psychoses in their offspring, and more commonly in male offspring which directly corresponded with infection severity.

The cohort sample included 15,421 pregnancies and outcomes (the women and the children they gave birth to), of which 23% experienced infection during pregnancy. Scientists used a variety of methods to measure the long-term relationship between maternal bacterial infection during pregnancy and psychotic disorders or psychotic symptomology in their offspring over the span of 40 years and concluded: “maternal bacterial infection during pregnancy was strongly associated with psychosis in offspring.” When the offspring were between the ages of 32 and 39, they were given comprehensive psychiatric evaluations. The evaluations showed that 216 offspring from mothers who had bacterial infections were confirmed to have symptoms of psychosis, 116 of which had been medically diagnosed with a psychotic disorder.

According to the National Institute of Mental Health, psychosis is described as conditions that affect the mind, where there has been some loss of contact with reality… with symptoms including delusions and hallucinations, incoherent or nonsense speech, and behavior that is inappropriate for the situation … a person in a psychotic episode may experience anxiety, depression, insomnia, lack of motivation, social withdrawal, and difficulty functioning overall.”

The underlying reasons for this phenomenon are not yet understood, but researchers hypothesize that an increased level of pro-inflammatory cytokines in the maternal immune system, placenta, and/or fetus itself caused by the bacterial infection is linked with risk of schizophrenia or other related psychosis in offspring. Further research and investigation is required.

Exposed male offspring had a three-fold higher risk of psychosis compared to non-exposed males, and exposed females, who, in the study, showed no difference in risk of psychosis compared to those unexposed to infection. The researchers in this study note that previous research has shown that healthy male fetuses have higher levels of pro-inflammatory cytokines, and enhanced inflammatory genetic activity, compared with females who tended to express higher levels of anti-inflammatory mediators and immunomodulatory genes.

These alarming results may motivate health care practitioners who work directly with pregnant patients to recommend safe strategies for preventing bacterial infections, as well as reducing the mother’s total inflammatory burden during pregnancy. These findings emphasize the importance that pregnant women supplement with high-quality prenatal vitamins to guard herself and the baby against inflammatory stressors such as pathogenic bacteria and pro-inflammatory cytokines. Conventional methods such as using antibiotics for bacterial infections are warranted when it comes to life-threatening situations during pregnancy, but dietary and herbal alternatives along with other natural strategies have profound benefits that can support a strong immune system gestation throughout fetal maturation. Educating mothers on eating clean, phytonutrient-rich diets from vegetables; fruits that are high in antioxidants to combat oxidative stress caused by inflammation; and vitamins and minerals that help reduce the risk of infections, is critical for bolstering the immune system.