Typical pregnancy length may vary more than thought - KTVN Channel 2 - Reno Tahoe News Weather, Video -

Typical pregnancy length may vary more than thought

Updated: Aug 7, 2013 10:04 AM
© iStockphoto.com / Ira Bachinskaya © iStockphoto.com / Ira Bachinskaya
  • Wendy Damonte's Health Watch ReportsMore>>

  • Request Remind Me 2 Kit

    Request a Remind Me 2 Kit

         More >>
  • New Treatment for Deaf Children

    New Treatment for Deaf Children

    Friday, July 25 2014 6:56 PM EDT2014-07-25 22:56:18 GMT
    An experimental procedure is giving deaf children the chance to hear. Doctors at Children's Hospital in Los Angeles are taking part in an experimental trial.More >>
    An experimental procedure is giving deaf children the chance to hear. Doctors at Children's Hospital in Los Angeles are taking part in an experimental trial.More >>
  • Free Yoga Classes for MS Patients in South Lake Tahoe

    Free Yoga Classes for MS Patients in South Lake Tahoe

    Friday, July 25 2014 4:34 PM EDT2014-07-25 20:34:18 GMT
    Multiple Sclerosis patients can get complimentary weekly yoga classes starting next month in South Lake Tahoe. The free MS Yoga Project weekly classes begin Monday, August 4th.More >>
    Multiple Sclerosis patients can get complimentary weekly yoga classes starting next month in South Lake Tahoe. The free MS Yoga Project weekly classes begin Monday, August 4th.More >>

WEDNESDAY, Aug. 7 (HealthDay News) -- The natural length of pregnancies can vary by as much as five weeks, according to a new study.

Pregnant women typically are given a likely birth date that is 280 days after the onset of their last menstrual period. Only 4 percent of women deliver at 280 days, however, and just 70 percent deliver within 10 days of their estimated due date.

The authors of the study said they're the first to find a way to pinpoint the precise point at which a woman ovulates and a fertilized embryo implants in the womb during a naturally conceived pregnancy, and to follow the pregnancy through to delivery.

This is done by analyzing women's urine for the presence of three hormones associated with the onset of pregnancy.

Using this information, the researchers were able to calculate the length of 125 pregnancies, according to the study, which was published Aug. 7 in the journal Human Reproduction.

"We found that the average time from ovulation to birth was 268 days -- 38 weeks and two days," Dr. Anne Marie Jukic, a postdoctoral fellow in the epidemiology branch at the U.S. National Institute of Environmental Health Sciences, said in a journal news release. "However, even after we had excluded six pre-term births, we found that the length of the pregnancies varied by as much as 37 days."

The researchers were "a bit surprised" by the finding.

"We know that length of gestation varies among women, but some part of that variation has always been attributed to errors in the assignment of gestational age," Jukic said. "Our measure of length of gestation does not include these sources of error, and yet there is still five weeks of variability. It's fascinating."

It's too early to make any clinical recommendations based on the findings and further research is required, the study authors said.

"I think the best that can be said is that natural variability may be greater than we have previously thought, and if that is true, clinicians may want to keep that in mind when trying to decide whether to intervene in a pregnancy," Jukic said.

More information

The U.S. Department of Health and Human Services outlines how to have a healthy pregnancy.

Copyright © 2013 HealthDay. All rights reserved.

*DISCLAIMER*: The information contained in or provided through this site section is intended for general consumer understanding and education only and is not intended to be and is not a substitute for professional advice. Use of this site section and any information contained on or provided through this site section is at your own risk and any information contained on or provided through this site section is provided on an "as is" basis without any representations or warranties.
Powered by WorldNow
All content © Copyright 2000 - 2014 WorldNow and Sarkes Tarzian, Inc. All Rights Reserved. For more information on this site, please read our Privacy Policy and Terms of Service.