Outdoor high temperature and low temperature are harmful to fetal growth during pregnancy

The study, published in the journal Environmental Health Perspectives, assessed the critical window period during which 624,940 single-born babies nationwide in Israel are susceptible to extreme low temperatures and high temperatures during pregnancy and fetal growth during 2010-2014

The research was led by Dr.

The researchers collected, mapped, modeled, and analyzed all recorded live birth data, residential information at birth, and outdoor temperature throughout pregnancy

Record live births

The birth certificate data for all live births comes from the National Registry of Births and Birth Defects of the Ministry of Health

Mapping residential information

The birth address is geocoded using geocoding services, such as HERE and Google, and the Israeli attribute mapping database GZIRNET, or converted to geographic coordinates

Hot or cold

According to data from the Israel Meteorological Agency, the daily temperature is estimated based on a time-space model with fine resolution scales (one-hour and one-square-kilometer resolution)

Climate zone division

Israel’s highly variable climate is determined by altitude, latitude, and location close to the Mediterranean.

Statistical Analysis

For each region, according to the distribution of all women in the cohort living in the climatic zone, the average daily temperature in different time periods (such as days, weeks, three months, and the entire pregnancy) is converted into percentiles

Next, the researchers conducted a statistical analysis to assess the relationship between temperature and birth weight, and based on the newborn’s race, religious group, gender, mother’s marital status, birth, age, education, socioeconomic class, and employment status.

result

A consistent association was observed between high temperature and low temperature and fetal birth weight

The correlation analysis between the average full-term birth weight of all three climatic zones and the percentile of the region-specific temperature shows an inverse U-shaped association, so that the coldest and warmest temperatures are correlated with the lower average full-term birth weight , Not related to the temperature in the middle of each distribution

From the average temperature throughout the pregnancy, the inverted U-shaped pattern is obvious

Pregnancy-specific associations also show an inverted U-shaped pattern, with the strongest associations at extreme temperatures in the late trimester

Analysis and recommendations

"Our research shows that in all full-term babies born in Israel within five years, there is a significant association between exposure to high and low temperature outdoor environments and birth weight

Determining the susceptible window period during pregnancy can clarify the underlying mechanisms and potential strategies to reduce the risk of pregnant women being exposed to extreme temperatures

As the temperature rises due to climate change, the researchers emphasized that public health organizations are recommended to develop strategies to address these challenges at the national and community levels

This research was funded by the Israel Science Foundation
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Xavier Basagaña, Yaron Michael, Itamar M.
Lensky, Lisa Rubin, Itamar Grotto, Elyakom Vadislavsky, Yoav Levi, Eyal Amitai, Keren Agay-Shay.
Low and High Ambient Temperatures during Pregnancy and Birth Weight among 624,940 Singleton Term Births in Israel (2010–2014): An Investigation of Potential Windows of Susceptibility .
Environmental Health Perspectives , 2021; 129 (10) DOI: 10.
1289/EHP8117