A  A  A   Print
Typical Pregnancy Length May Vary More Than Thought

Typical Pregnancy Length May Vary More Than Thought

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.

SOURCE: Human Reproduction, news release, Aug. 7, 2013

 
Today's Interactive Tools

The third-party content provided in the Health Library of phoebeputney.com is for informational purposes only and is not designed to diagnose or treat a health problem or disease, or replace the professional medical advice you receive from your physician. If you or your child has or suspect you may have a health problem, please consult your primary care physician. If you or your child may have a medical emergency, call your doctor or 911 or other emergency health care provider immediately in the United States or the appropriate health agency of your country. For more information regarding site usage, please visit: Privacy Information, Terms of Use or Disclaimer.

Follow us online:

© 2014 Phoebe Putney Health System  |  417 Third Avenue, Albany, Georgia 31701  |  Telephone 877.312.1167

Phoebe Putney Health System is a network of hospitals, family medicine clinics, rehab facilities, auxiliary services, and medical education training facilities. Founded in 1911,
Phoebe Putney Memorial Hospital (the flagship hospital) is one of Georgia's largest comprehensive regional medical centers. From the beginning, Phoebe's mission and vision
has been to bring the finest medical talent and technology to the citizens of Southwest Georgia, and to serve all citizens of the community regardless of ability to pay.