Fever and infections during pregnancy and psychosis-like experiences in the offspring at age 11. A prospective study within the Danish National Birth Cohort.

BACKGROUND: Maternal exposures to fever and infections in pregnancy have been linked to subsequent psychiatric morbidity in the child. This study examined whether fever and common infections in pregnancy were associated with psychosis-like experiences (PLEs) in the child. METHODS: A longitudinal study of 46 184 children who participated in the 11-year follow-up of the Danish National Birth Cohort was conducted. Pregnant women were enrolled between 1996 and 2002 and information on fever, genitourinary infections, respiratory tract infection, and influenza-like illness during pregnancy was prospectively collected in two interviews during pregnancy. PLEs were assessed using the seven-item Adolescent Psychotic-Like Symptom Screener in a web-based questionnaire completed by the children themselves at age 11. RESULTS: PLEs were reported among 11% of the children. Multinomial logistic regression models with probability weights to adjust for potential selection bias due to attrition suggested that maternal fever, genitourinary infections and influenza-like illness were associated with a weak to moderate increased risk of subclinical psychosis-like symptoms in the offspring, whereas respiratory tract infections were not. No clear pattern was observed between the strengths of the associations and the timing of exposure, or the type of psychosis-like symptom. CONCLUSIONS: In this study, maternal exposures to fevers and common infections in pregnancy were generally associated with a subtle excess risk of PLEs in the child. A more pronounced association was found for influenza-like illness under an a priori definition, leaving open the possibility that certain kinds of infections may constitute important risk factors.

Fever in pregnancy and the risk of congenital malformations: a cohort study.

BACKGROUND: In a variety of animal species, hyperthermia in pregnancy has been recognized as teratogenic. Hyperthermia interferes with protein synthesis via heat-shock proteins, which can entail membrane disruption, cell death, vascular disruption, and placental infarction. This can induce severe fetal malformations or death. Fever during pregnancy, especially during embryogenesis, has also been associated with congenital malformations in human offspring. The purpose of this large cohort study of clinically recognized pregnancies was to investigate whether fever during first trimester was associated with an increased risk of congenital malformations in the offspring. METHODS: The Danish National Birth Cohort is a population-based cohort of 100,418 pregnant women and their offspring recruited in 1996 to 2002. Information on fever during pregnancy was collected prospectively by means of two telephone interviews. The study population comprised the 77,344 pregnancies enrolled in the Danish National Birth Cohort where self-reported information on fever during first trimester of pregnancy was available. Pregnancy outcomes were identified through linkage with the National Patient Registry. Congenital malformations within the first three and a half years of life were categorized according to EUROCAT's classification criteria. Logistic regression models were used to estimate the associations between fever in first trimester and overall congenital malformations and congenital malformations by subgroups. RESULTS: Eight thousand three hundred twenty-one women reported fever during first trimester (10.8%) and 2876 infants were diagnosed with a congenital malformation (3.7%). Fever during first trimester did not affect the risk of overall fetal congenital malformation (OR 0.99, 95% CI 0.88-1.12). The subgroup analyses indicated slightly higher risk of congenital anomalies in the eye, ear, face and neck (OR 1.29, 95% CI 0.78-2.12) and in the genitals (OR 1.17, 95% CI 0.79-1.12), whereas lower risk of malformations in the nervous system (OR 0.47, 95% CI 0.21-1.08), the respiratory system (OR 0.56, 95% CI 0.23-1.29) and in the urinary subgroup (OR 0.58, 95% CI 0.35-0.99) was suggested, the latter constituting the only statistically significant finding. CONCLUSIONS: Overall, this study did not show any association between maternal fever in pregnancy and risk of congenital anomalies.