Associations between prenatal exposure to ambient temperature and birthweight small-for-gestational-age: an integrative model

percentile) was assessed. We conducted a two-stage analysis: (1) stratifying the cohort by gestation length and using distributed lag models to estimate temperature-SGA associations across pregnancy weeks, and (2) integrating these results into a weighted mean estimate. Overall, higher temperatures were weakly associated with a lower risk of SGA, with significant associations starting from the third trimester, reaching 0.93 (95% CI: 0.88-0.98) and 1.08 (95% CI: 1.01-1.16) for exposure to 38°C and 2°C, respectively, at 40 weeks, particularly in the Arab sub-population. In early preterm births, mid-pregnancy exposure to higher temperatures was strongly linked to increased SGA risk. The association varies across gestation lengths, with distinct critical windows, which underscore the importance of preterm inclusion when studying prenatal exposure and birth outcomes.