Effect of Febrile Rhinovirus Illness During Pregnancy on Adverse Birth Outcomes in Nepal

Background: Adverse birth outcomes, including low birthweight (LBW), small-for-gestational-age (SGA) and preterm birth, contribute to 60-80% of infant mortality worldwide. Infection during pregnancy is associated with adverse birth outcomes. We sought to identify whether febrile human rhinovirus-positive influenza-like-illness (HRV-ILI) during pregnancy was associated with adverse birth outcomes.

Methods: We utilized data collected in a community-based, prospective randomized trial of maternal influenza immunization of pregnant women and their infants conducted in rural Nepal from 2011-2014. Illness episodes were defined as fever plus cough, sore throat, runny nose, and/or myalgia. Respiratory illnesses were identified through longitudinal household-based weekly surveillance. Respiratory swabs were collected with illness episodes and tested for HRV by PCR. The χ²-test, two-sample t-test, and logistic regression were performed to evaluate baseline characteristics and the association of HRV-ILI during pregnancy with adverse birth outcomes.

Results: HRV was the most frequent cause of ILI in the peripartum period (n=189/3693; 5%). HRV-ILI occurred year-round with a peak in October. Median maternal age, parity, biomass cook stove use, smoking, caste, and water source did not differ in pregnant women with and without HRV-ILI. Prevalence of LBW was significantly higher among infants born to pregnant women with HRV-ILI compared to those not exposed (28/76 (37%) vs 652/2688 (24%), respectively; crude OR, 1.82; 95% CI, 1.13-2.93). The effect was primarily restricted to mothers with HRV-ILI in the second trimester of pregnancy (17/42; 40%). Mean birthweight was 2689 gms (SD: 495) in the exposed group vs 2786 gms (SD: 453) in the unexposed group (P=0.06). A trend towards increased SGA among HRV-ILI exposed infants was identified (35/76 (46%) in exposed vs 1018/2612 (39%) in unexposed; P=0.16). No significant difference in preterm delivery was found.

Conclusion: Febrile HRV illness during pregnancy was associated with a higher rate of low birthweight infants in this rural South Asian population. Interventions to reduce the burden of febrile respiratory illness during pregnancy may have an impact on low birthweight in resource-limited settings.