Universal Thermal Climate Index (UTCI) and adverse pregnancy outcomes in Ahvaz, Iran

Reprod Health. 2022 Feb 2;19(1):33. doi: 10.1186/s12978-022-01344-7.

Abstract

Background: Climate change may jeopardize the health of mothers and their offspring. There are few studies on the association between increasing temperature and pregnancy outcomes. The aim of this study was to investigate the relation between Universal Thermal Climate Index (UTCI) and adverse pregnancy outcomes including stillbirth, low birth weight (LBW), preterm labor (PTL), spontaneous abortion (SA), preeclampsia and hypertension in Ahvaz, Iran.

Methods: Distributed Lag Non-linear Models (DLNM) combined with quasi-Poisson regression were used to research the effect of UTCI on adverse pregnancy outcomes. The effect of time trend, air pollutants (NO2, SO2 and PM10), and weekdays were adjusted.

Results: The results showed that the low values of UTCI index (11.6 °C, in lags 0-6, 0-13) caused significant increase in the risk of preterm labor. However, hot thermal stress (high UTCI) significantly increased the risk of stillbirth in lag 0-13. We did not observe any significant relation between UTCI and other pregnancy outcomes in this study.

Conclusions: It seems like both hot and cold weathers can be associated with adverse pregnancy outcomes.

Keywords: Pregnancy outcome; Temperature; Thermal index; Universal Thermal Climate Index.

Plain language summary

Scientists have found that climate change has adverse effects on human health. Because pregnant women are one of the most vulnerable groups, these negative impacts may affect their fetuses, which make up the next generation. In this study, we examined the effect of temperature on some pregnancy outcomes, including low birth weight, preterm labor, spontaneous abortion, preeclampsia and gestational hypertension in Ahvaz city, which is one of the hottest cities in the world.One way to assess temperature impact on humans is by using temperature indicators. In this study we used the Universal Thermal Climate Index (UTCI) for this purpose. The data at different time intervals were collected and evaluated with specific models.Our results showed that low values of UTCI, which is equivalent to cold weather, significantly increase the risk of preterm labor. But, high levels of UTCI, which means hot weather, significantly increase the risk of stillbirth.In conclusion; both hot and cold weather can be associated with adverse pregnancy outcomes in Ahvaz city. Therefore, pregnant women should protect themselves from exposure to hot and cold weather.

MeSH terms

  • Abortion, Spontaneous*
  • Female
  • Humans
  • Infant, Newborn
  • Iran / epidemiology
  • Pregnancy
  • Pregnancy Outcome* / epidemiology
  • Stillbirth / epidemiology