Impact of ambient temperature exposure on newborns with low Apgar scores in northwest China.

In the context of global climate change, research efforts were focused on the association of ambient temperatures on maternal and neonatal health condition, but few have examined associations with low Apgar scores. From January 1, 2017, to December 31, 2018, all singleton deliveries of Ningxia Hui Autonomous Region were extracted from the Hospital Information System (N = 182,322). Daily temperature data were obtained from the official website of China Meteorological Administration. Low Apgar scores were defined as Apgar score ≤ 3 at 5 min in the present study. Logistic regression models were used to estimate the adjusted association between prenatal temperature exposure and low Apgar scores. Restricted cubic spline models were used to explore the dose-response relationship between temperature and low Apgar scores. The study population included 182,322 live singleton births, with 1575 (0.86%) cases of low Apgar scores. The elevated ambient temperature in different exposure timing windows in late pregnancy was associated with increased risk of low Apgar scores. As compared to moderate (10th-90th) temperature exposure, prenatal exposure to extreme hot (>90th) was associated with 13.9-47.0% increased risk of low Apgar scores, while non-significant relationship was found between extreme cold (<10th) exposure and low Apgar scores. The restricted cubic spline models showed a U-shaped relationship between prenatal temperature exposure and low Apgar scores (P for non-linearity < 0.05). Exposure to high ambient temperature during late pregnancy is associated with an increased risk of low Apgar scores in northwest China.