Season of conception and neurodevelopmental outcomes in singleton preterm infants less than 29 weeks gestation

Smita Roychoudhury; Selphee Tang; Shabih U Hasan; Kevin Fonseca; Abhay Lodha; Belal Alshaikh; Essa Alawad; Kamran Yusuf

doi:10.3389/fped.2025.1492429

Season of conception and neurodevelopmental outcomes in singleton preterm infants less than 29 weeks gestation

Front Pediatr. 2025 Mar 27:13:1492429. doi: 10.3389/fped.2025.1492429. eCollection 2025.

Authors

Smita Roychoudhury¹, Selphee Tang², Shabih U Hasan³, Kevin Fonseca⁴, Abhay Lodha³, Belal Alshaikh³, Essa Alawad³, Kamran Yusuf³

Affiliations

¹ Department of Pediatrics, McMaster University, Hamilton, ON, Canada.
² Alberta Health Services, Calgary, AB, Canada.
³ Department of Pediatrics, Section of Neonatology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.
⁴ Department of Microbiology, Immunology and Infectious Diseases, University of Calgary and Alberta Precision Laboratories, Calgary, AB, Canada.

Abstract

Background: Environmental factors vary with the seasons and affect fetal development. Our objective was to assess the impact of the season of conception on neurodevelopmental outcomes at 18-21 months corrected age in singleton infants <29 weeks' gestation.

Methods: A retrospective cohort study of infants born between 2006 and 2015 at a tertiary-level neonatal intensive care unit was conducted. The conception date was calculated as the date of birth minus gestational age plus 14 days, and the conception dates were then divided into winter and non-winter months. The primary outcomes were a composite score of <85 in any of the cognitive, language, or motor components of the Bayley Scales of Infant and Toddler Development, 3rd edition (Bayley-III), at 18-21 months corrected gestational age, and scores of <85 in the individual components. Multivariate logistic regression was used to assess confounders.

Results: Of the 493 eligible infants, 162 (32.8%) were conceived in winter. There was no difference in the adjusted odds ratios (aORs) of any Bayley-III cognitive, language, or motor composite scores of <85 between the two groups. The aORs of cognitive and language scores <85 in the winter group were significantly higher [2.78, 95% confidence interval (CI) 1.37-5.65 and 1.97, 95% CI 1.07-3.62, respectively].

Conclusion: Singleton infants <29 weeks' gestation conceived in winter months have worse cognitive and language outcomes. Our results need validation in other and larger cohorts.

Keywords: Bayley III; month of conception; neurodevelopmental outcome; preterm infant; winter months.

Grants and funding

The authors declare that financial support was received for the research and/or publication of this article. The study was funded by a Small Research Grant from the Alberta Children’s Hospital Research Institute, University of Calgary.