Featured Research

from universities, journals, and other organizations

Heat waves reduce length of pregnancy

Date:
April 1, 2014
Source:
Universite de Montreal
Summary:
When temperatures reach 32C or higher over a period of four to seven days, the risk of early-term delivery is 27% higher than on typical summer days, according to a study. The research team sought to identify, from June through September, the probability of preterm (less than 37 gestational weeks), early-term (37-38 weeks), and full-term (39 weeks or more) deliveries during a heat wave. Specifically targeting summer births, Auger found that nearly 20,000 deliveries occurred in the week following a day when the mercury reached 32C or higher.

When temperatures reach 32C or higher over a period of four to seven days, the risk of early-term delivery is 27% higher than on typical summer days, according to a study led by Nathalie Auger of the University of Montreal's Department of Social and Preventive Medicine. The study involved data from 300,000 births that took place in Montreal between 1981 to 2010 with summer temperatures recorded by Environment Canada during this period. Auger is also affiliated with the university's CHUM Superhospital Research Centre.

The research team sought to identify, from June through September, the probability of preterm (less than 37 gestational weeks), early-term (37-38 weeks), and full-term (39 weeks or more) deliveries during a heat wave. Specifically targeting summer births, Auger found that nearly 20,000 deliveries occurred in the week following a day when the mercury reached 32C or higher.

After adjusting for certain variables, including age of mother, birth order, and humidity during heat waves, Auger found that extreme heat did not seem to increase the number of preterm births. "We observed a only a negligible increase in the rate of preterm births between days when the temperature was below 20C and those when it was above 28C, from 5.4% to 5.8%," Auger explained. However, in women who reached 37 or 38 weeks of pregnancy, the risk of early-term delivery increased by 17% following a three-day episode of 32C or more, compared to days without a heat wave. When the extreme heat episode lasted from 4 to 7 days, the risk reached 27%.

Impact on early-term newborns?

According to Auger, the adverse effects of high temperatures on the elderly are well documented, but little research has dealt with the impact of heat on pregnant women. "Small-scale studies suggest that heat-induced stress increases uterine contractility, during a period of pregnancy when thermoregulation seems less effective," Auger said. "We also suspect that dehydration resulting from high ambient temperature reduces the blood supply to the uterus, increasing the release of pituitary hormones that induce labour."

Auger believes that the increased risk of early-term delivery due to high temperatures may result in increased morbidity in newborns. "Studies have shown that children born at 37 or 38 weeks suffer more respiratory problems compared with children born at term," Auger said. "Early-term newborns are also at greater risk of death."


Story Source:

The above story is based on materials provided by Universite de Montreal. Note: Materials may be edited for content and length.


Journal Reference:

  1. Nathalie Auger, Ashley I. Naimi, Audrey Smargiassi, Ernest Lo, Tom Kosatsky. Extreme Heat and Risk of Early Delivery Among Preterm and Term Pregnancies. Epidemiology, 2014; 1 DOI: 10.1097/EDE.0000000000000074

Cite This Page:

Universite de Montreal. "Heat waves reduce length of pregnancy." ScienceDaily. ScienceDaily, 1 April 2014. <www.sciencedaily.com/releases/2014/04/140401101849.htm>.
Universite de Montreal. (2014, April 1). Heat waves reduce length of pregnancy. ScienceDaily. Retrieved July 30, 2014 from www.sciencedaily.com/releases/2014/04/140401101849.htm
Universite de Montreal. "Heat waves reduce length of pregnancy." ScienceDaily. www.sciencedaily.com/releases/2014/04/140401101849.htm (accessed July 30, 2014).

Share This




More Health & Medicine News

Wednesday, July 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Health Insurers' Profits Slide

Health Insurers' Profits Slide

Reuters - Business Video Online (July 30, 2014) Obamacare-related costs were said to be behind the profit plunge at Wellpoint and Humana, but Wellpoint sees the new exchanges boosting its earnings for the full year. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
Concern Grows Over Worsening Ebola Crisis

Concern Grows Over Worsening Ebola Crisis

AFP (July 30, 2014) Pan-African airline ASKY has suspended all flights to and from the capitals of Liberia and Sierra Leone amid the worsening Ebola health crisis, which has so far caused 672 deaths in Guinea, Liberia and Sierra Leone. Duration: 00:43 Video provided by AFP
Powered by NewsLook.com
At Least 20 Chikungunya Cases in New Jersey

At Least 20 Chikungunya Cases in New Jersey

AP (July 30, 2014) At least 20 New Jersey residents have tested positive for chikungunya, a mosquito-borne virus that has spread through the Caribbean. (July 30) Video provided by AP
Powered by NewsLook.com
Xtreme Eating: Your Daily Caloric Intake All On One Plate

Xtreme Eating: Your Daily Caloric Intake All On One Plate

Newsy (July 30, 2014) The Center for Science in the Public Interest released its 2014 list of single meals with whopping calorie counts. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

    Environment News

    Technology News



      Save/Print:
      Share:

      Free Subscriptions


      Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

      Get Social & Mobile


      Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

      Have Feedback?


      Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
      Mobile: iPhone Android Web
      Follow: Facebook Twitter Google+
      Subscribe: RSS Feeds Email Newsletters
      Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins