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.

Related Articles


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 March 30, 2015 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 March 30, 2015).

Share This


More From ScienceDaily



More Health & Medicine News

Monday, March 30, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

S. Leone in New Anti-Ebola Lockdown

S. Leone in New Anti-Ebola Lockdown

AFP (Mar. 28, 2015) Sierra Leone imposed a three-day nationwide lockdown Friday for the second time in six months in a bid to prevent a resurgence of the deadly Ebola virus. Duration: 01:17 Video provided by AFP
Powered by NewsLook.com
These Popular Antibiotics Can Cause Permanent Nerve Damage

These Popular Antibiotics Can Cause Permanent Nerve Damage

Newsy (Mar. 27, 2015) A popular class of antibiotic can leave patients in severe pain and even result in permanent nerve damage. Video provided by Newsy
Powered by NewsLook.com
WH Plan to Fight Antibiotic-Resistant Germs

WH Plan to Fight Antibiotic-Resistant Germs

AP (Mar. 27, 2015) The White House on Friday announced a five-year plan to fight the threat posed by antibiotic-resistant bacteria amid fears that once-treatable germs could become deadly. (March 27) Video provided by AP
Powered by NewsLook.com
House Ready to Pass Medicare Doc Bill

House Ready to Pass Medicare Doc Bill

AP (Mar. 26, 2015) In rare bipartisan harmony, congressional leaders pushed a $214 billion bill permanently blocking physician Medicare cuts toward House passage Thursday, moving lawmakers closer to resolving a problem that has plagued them for years. (March 26) Video provided by AP
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:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

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