Association between Physiological Equivalent Temperature (PET) with adverse pregnancy outcomes in Ahvaz, southwest of Iran

Maryam Dastoorpoor,Narges Khodadadi,Narges Khanjani

doi:10.1186/s12884-021-03876-5

Abstract

BackgroundThere are few epidemiological studies on the relation between temperature changes and adverse pregnancy outcomes. The purpose of this study was to determine the relation between Physiological Equivalent Temperature (PET) with adverse pregnancy outcomes including stillbirth, low birth weight (LBW), preterm labor (PTL), spontaneous abortion (SA), preeclampsia and hypertension in Ahvaz, Iran.MethodsDistributed Lag Non-linear Models (DLNM) combined with quasi-Poisson regression were used to investigate the effect of PET on adverse pregnancy outcomes. In this study the effect of time trend, air pollutants (NO2, SO2 and PM10), and weekdays were adjusted.ResultsHigh PET (45.4 C°, lag = 0) caused a significant increase in risk of stillbirth. Also, high levels of PET (45.4, 43.6, 42.5 C°, lag = 0–6) and low levels of PET (9.9, 16.9 C°, lags = 0, 0–13, 0–21) significantly increased the risk of LBW. But, low levels of PET (6.4, 9.9, 16.9 C°, lags = 0–6, 0–13) reduced the risk of gestational hypertension.ConclusionThe results of this study showed that hot and cold thermal stress may be associated with increased risk of stillbirth, and LBW in Ahvaz.

Highlights

There are few epidemiological studies on the relation between temperature changes and adverse pregnancy outcomes
The aim of the present paper is to study the relation between Physiological Equivalent Temperature (PET) and stillbirth, low birth weight (LBW), preterm labor (PTL), spontaneous abortion (SA), preeclampsia and gestational hypertension in a 10 year (2008–2018) time frame in Ahvaz, Iran
NO2d(μg/m3) SO2e PM10f PET g aLow birth weight bPreterm labor cSpontaneous abortion dNitrogen dioxide eSulfur dioxide fParticulate matter less than 10 microns gPhysiological equivalent temperature

Summary

Introduction

There are few epidemiological studies on the relation between temperature changes and adverse pregnancy outcomes. The purpose of this study was to determine the relation between Physiological Equivalent Temperature (PET) with adverse pregnancy outcomes including stillbirth, low birth weight (LBW), preterm labor (PTL), spontaneous abortion (SA), preeclampsia and hypertension in Ahvaz, Iran. Heat stress is a major cause of climate-related deaths. As temperatures continue to increase due to climate change, heat stress is expected to worsen [2]; and negative outcomes might increase as a result of human exposure to extreme weather conditions. Researchers think one of the most important weather-related causes of mortality in the developed and developing world, is Recently, several studies have focused on the possible effects of ambient temperature on pregnancy outcomes. Other studies have reported a positive relation between exposure to heat waves in all months

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