Researchers have recently identified that children born to mothers who suffer from influenza while pregnant are more likely to experience seizures in childhood, with febrile seizures being the most common type. A recent study was published in the journal JAMA Network Open by Yi-Feng Lee and colleagues.
Seizure disorders are probably the most common neurological disorders in infants and toddlers, and various factors during pregnancy have been associated with this condition. Specifically, infections occurring during pregnancy have been known to link with a higher risk for childhood seizures. The current article reports the results of a 16-year prospective investigation related to how influenza infection during pregnancy might increase the risk of seizures in children.

The study screened mother-offspring pairs extracted between January 1, 2004 and December 31, 2013 from Taiwan's Maternal and Child Health Database. A total number of mother-offspring pairs were 1,316,107. Mothers who experienced influenza during pregnancy were allocated to the influenza-exposed group (75,835 mothers, predominant age, 25-29 years), while mothers without influenza exposure during pregnancy were allocated to the control group (1,240,272 mothers, predominant age, 30-34 years). The control mothers were also selected with a ratio of 1:4 based on the maternal age, offspring sex, and date of delivery. The offspring were followed through to 31st December 2020 to calculate seizure incidence.
Maternal flu infection was defined using ICD codes. It stated two main outcomes as risks of any seizure in the children which include epilepsy as well as febrile seizures. It calculated AHRs to estimate the risk adjusting for confounding factors like pregnancy complications.
The findings of the study showed that exposure to maternal influenza before birth increased the risk in childhood for any type of seizures by 9% more than in a control group.

• 1.09 AHR (95% CI, 1.05-1.14) for any seizures
• 1.11 AHR (95% CI, 1.06-1.17) for febrile seizures for which an increase in risk at a statistically significant level;
• 1.04 AHR (95% CI, 0.97-1.13) for epilepsy.
• The prevalence of complications of pregnancy, including placenta previa or abruption, was higher in mothers in the influenza group (1.6% [1241]) than in the control group (1.4% [4350]; P < 0.001).
Subgroup analyses regarding the time of influenza infection that is, in the first, second, or third trimester did not exert a statistically significant effect on the risk of seizures suggesting that the increase in risk was consistent with whatever trimester the infection occurred during pregnancy.
These findings support maternal influenza infection during pregnancy as being associated with a modestly elevated childhood seizure risk, although specifically, an increased risk of febrile seizures only, but not epilepsy. The implications for early neurological development have been highlighted that occur subsequent to prenatal exposure to influenza, which is supported by an indication for further research regarding the mechanisms that underpin the observed alterations. Maternal influenza infection-preventing interventions may also reduce children's risk of developing seizures; vaccination is an example of such a measure.
Reference:
Lee, Y.-F., Lin, Y.-H., Lin, C.-H., & Lin, M.-C. (2024). Influenza infection during pregnancy and risk of seizures in offspring. JAMA Network Open, 7(9), e2434935. https://doi.org/10.1001/jamanetworkopen.2024.34935