Offspring seizure risk associated with maternal influenza

Offspring seizure risk associated with maternal influenza | Image Credit: © adipurnatama - © adipurnatama - stock.adobe.com.

The risk of childhood seizures is increased by maternal influenza infections during pregnancy, according to a recent study published in JAMA Network Open.¹

Seizures lead to altered movements, behaviors, feelings, and consciousness status, with febrile seizure being the most common neurological issue among children aged 6 years and younger. Investigators have hypothesized major lifetime health impacts from periconceptual, prenatal, and early extrauterine environmental stressors.

Certain neurological sequelae in offspring are impacted by maternal bacterial infections in pregnancy, with prenatal influenza exposure indicated as a potential risk factor of childhood seizures. However, this association has only been reported in Western countries, with data in East Asian countries lacking.

Influenza vaccination during pregnancy has been associated with increased infant protection, based on the results of a prospective test-negative study.² Infants of mothers who received influenza vaccination also had improved protection against the disease, with only 26.8% of positive influenza cases being reported among infants of mothers who were vaccinated.

Of infants who tested negative, 35.6% had mothers who were vaccinated during pregnancy. Rates of vaccination among mothers testing positive and negative for influenza were 28.6% and 38.3%, respectively, highlighting the benefits of maternal influenza protection.

To evaluate the link between maternal influenza infection and childhood seizures, investigators conducted a nationwide cohort study.¹ Data was obtained from Taiwan’s Maternal and Child Health Database, which linked multiple relevant datasets to provide comprehensive data about parents and offspring.

Participants included mother-offspring pairs from January 1, 2004, to December 31, 2013, with follow-up occurring until December 31, 2020. Mothers with a history of epilepsy were excluded from the analysis. Mothers were primiparous and had an outpatient visit, emergency department visit, hospitalization with a primary influenza diagnosis.

Influenza diagnosis was determined based on International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) or ICD-10-CM codes, and patients without influenza during pregnancy were matched 1:4 to those with influenza. Any seizure diagnosis was reported as the primary outcome of the analysis.

Seizure types included epilepsy and febrile seizures. Covariates included gestational hypertension, gestational diabetes, preeclampsia or eclampsia, placenta previa or abruption, and anemia.

There were 1,316,107 mother-offspring pairs included in the analysis, with a predominant maternal age of 25 to 29 years. Of offspring, 48.1% of female offspring and 51.9% of male offspring were in the influenza group. The rate of placenta previa was slightly increased in the influenza group vs the control group, at 1.6% vs 1.4%, respectively.

Higher rates of seizures were reported in the influenza group vs the control group, with 3.2% of infants in the influenza group developing seizures during follow-up. When evaluating this risk based on seizure type, an elevated risk did not remain for epilepsy, but the risk of febrile convulsions was significantly increased.

When controlling for confounders, the adjusted hazard ratios (aHRs) in the influenza group were 1.09 for seizures, 1.11 for febrile convulsions, and 1.04 for epilepsy. Significant covariates included maternal age, gestational hypertension, cesarean delivery, male offspring sex, birth weight, and gestational age, with aHRs of 0.90, 1.78, 1.09, 1.28, 1.27, and 1.23, respectively.

These results indicated an association between maternal influenza infection during pregnancy and an increased risk of febrile seizures in offspring. Investigators recommended additional research evaluating the mechanisms underlying childhood neurological development.

References:

1. Lee Y, Lin Y, Lin C, Lin M. Influenza infection during pregnancy and risk of seizures in offspring. JAMA Netw Open. 2024;7(9):e2434935. doi:10.1001/jamanetworkopen.2024.34935
2. Krewson C. Maternal influenza vaccination during pregnancy protects infants. November 30, 2022. Accessed September 23, 2024. https://www.contemporaryobgyn.net/view/maternal-influenza-vaccination-during-pregnancy-protects-infants

This article was initially published by our sister publication, Contemporary OB/GYN®.