Short-term effects of ambient temperature on the risk of premature rupture of membranes in Xinxiang, China: A time-series analysis

Background: Studies on the effects of extreme ambient temperature on the risk of adverse birth outcomes are limited, and the results arc inconsistent. In this study, we evaluated the short-term effects of daily mean temperature on the risk of premature rupture of membranes (PROM) in Xinxiang, China. Methods: Daily hospitalization data for PROM, daily meteorological data, and ambient pollution data in Xinxiang from January 1, 2015 to December 31, 2017 were collected. A quasi-Poisson generalized additive model (GAM) combined with a distributed lag non-linear model (DLNM) was applied to assess the short-term impact of temperature on PROM. The model was adjusted for relative humidity, air pollution, time trend, day of the week, and public holidays. Results: The number of daily hospitalizations for PROM during the study period was 3255. With a reference median temperature of 17 degrees C, there were significant associations between the temperature deviation from the threshold temperature (2 degrees C, 12th percentile; 29 degrees C, 91st percentile) and PROM hospitalization at lag 0-2 days. Exposure to extreme cold (-2 degrees C, 1st percentile) or extreme heat (32 degrees C, 99th percentile) were associated with 0.528 (95% confidence interval [CI]: 0.278-0.986) and 2.161 (95% CI, 1.240-3.764) increased risks of PROM, respectively. Younger mothers with age <35 years were more sensitive to the impact of extreme temperature. Conclusions: These findings suggest that heat temperature is associated with higher PROM risk, while cold temperature might be a protective factor against PROM in Xinxiang, China. Given the adverse consequences of PROM and concerns over global climate change, pregnant women should take special precautions in summer when there are sudden increases in temperature. (C) 2019 Elsevier B.V. All rights reserved.