Featured Research

from universities, journals, and other organizations

Genes of pregnant women and their fetuses can increase risk of preterm labor

Date:
February 4, 2010
Source:
NIH/National Institute of Child Health and Human Development
Summary:
New evidence that genetics play a significant role in some premature births may help explain why a woman can do everything right and still give birth too soon. Researchers have identified DNA variants in mothers and fetuses that appear to increase the risk for preterm labor and delivery.

New evidence that genetics play a significant role in some premature births may help explain why a woman can do everything right and still give birth too soon. Researchers at the National Institutes of Health have identified DNA variants in mothers and fetuses that appear to increase the risk for preterm labor and delivery. The DNA variants were in genes involved in the regulation of inflammation and of the extracellular matrix, the mesh-like material that holds cells within tissues.

"A substantial body of scientific evidence indicates that inflammatory hormones may play a significant role in the labor process," said Alan E. Guttmacher, M.D., acting director of the NIH's Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD). "The current findings add evidence that individual genetic variation in that response may account for why preterm labor occurs in some pregnancies and not in others."

Like sensitivity to allergens such as house dust or pollen, the severity of the immune response appears to vary from individual to individual, accounting for why some pregnancies end in early labor and delivery. The findings may one day lead to new strategies to identify those at risk for preterm birth, and to ways to reduce the occurrence of preterm birth among those at risk.

The findings were presented February 4 at the 30th Annual Society for Maternal-Fetal Medicine meeting by Dr. Roberto Romero, M.D, chief of the perinatology research branch and program head for perinatal research and obstetrics at the NICHD. At the meeting, Dr. Romero and his team received the March of Dimes Excellence Award for innovative research on preterm birth for this study.

Premature birth affects 13 million infants worldwide each year.According to the National Center for Health Statistics, roughly one half million preterm births occur in the United States each year. Infants born preterm are at risk for infant death, life-threatening infections, blindness, breathing problems, learning and developmental disabilities, and cerebral palsy.

The finding is the most recent in a body of research by Dr. Romero and his colleagues. On the basis of earlier studies, the scientists had determined that an estimated 1 of every 3 preterm infants is born to a mother who has a silent infection of the amniotic fluid. A silent infection is one which does not show any outward signs or symptoms.

Dr. Romero described pregnancy as a unique state in which two genetically distinct organisms -- mother and fetus -- must coexist. Each fights infection by using hormones that stimulate the immune system. Hormones which play a role in immunity also play a role in labor. When released by either the mother, or the fetus, these hormones set in motion a cascade of events that can cause labor to begin.

"Our hypothesis is that the mother and/or the fetus signal the onset of preterm labor when the environment inside the uterus is unfavorable and threatens the survival of the maternal-fetal pair," Dr. Romero said.

Similar to sensitivity to allergens such as dust mites or pollen, the intensity of the immune response varies greatly, depending on genetic factors, the scientists theorize. Presumably, this genetic variability in the immune response accounts for why some pregnancies progress to full term, while others end early,

"When there is an infection in the uterus, the onset of premature labor appears to have survival value," Dr. Romero said. "In the presence of infection, premature labor would allow the mother to rid herself of the infected tissue and preserve her ability to have future pregnancies. If premature labor occurs too early, babies may not survive." If premature labor due to infection occurs late in pregnancy, it may be life-saving for both mother and fetus.

Along with genes controlling the inflammatory response, the physician-scientists also found that DNA variants in genes active in the extracellular matrix were also linked to premature labor. The extracellular matrix is the mesh-like material that holds cells within tissues. The maternal and fetal genes that Dr. Romero and his colleagues identified regulate the amount of extracellular matrix in the uterus. The extracellular matrix of the uterine cervix and of the membranes containing the embryonic fluid are broken down at the beginning of labor.

To conduct the study, the scientists evaluated 190 genes and more than 700 DNA variants in samples from 229 women and 179 premature infants, and a large number of women who delivered at term. The study was conducted on a population of women in Chile. All of the women in the study were of Hispanic origin (of largely white and Native American backgrounds.). The study is one of the few to look at the genetic factors governing birth in an exclusively Hispanic population.

Infants who carried the DNA variant in the gene for the Interleukin 6 receptor were more likely to be born premature than those who did not. Interleukin 6 is produced by cells in response to infection and is involved in inflammation. In previous studies, Dr. Romero and his team found that high levels of Interleukin 6 in the amniotic fluid and in the fetal blood are associated with the beginning of premature labor.

Dr. Romero noted that molecules responsible for inflammation such as Interleukins 1 and 6 predate the human species and even mammals. He added that Interleukin 1-like molecules are even present in primitive organisms, such as sponges (which do not undergo labor). The primary function of these molecules is to fight infection. However, in most mammals, these molecules are not only used by the immune system to fight infection, but also play a role in triggering the onset of labor.

Also participating in the study were researchers from Wayne State University, Detroit; the University of Miami; the Dr. John T. MacDonald Foundation, Coral Gables, Fla.; Emory University, Atlanta; Vanderbilt University, Nashville; Genaissance Pharmaceuticals (now part of Clinical Data, Newton, Mass.); and Sotero del Rio Hospital and The Pontifical Catholic University of Chile, both in Santiago, Chile.


Story Source:

The above story is based on materials provided by NIH/National Institute of Child Health and Human Development. Note: Materials may be edited for content and length.


Cite This Page:

NIH/National Institute of Child Health and Human Development. "Genes of pregnant women and their fetuses can increase risk of preterm labor." ScienceDaily. ScienceDaily, 4 February 2010. <www.sciencedaily.com/releases/2010/02/100204075029.htm>.
NIH/National Institute of Child Health and Human Development. (2010, February 4). Genes of pregnant women and their fetuses can increase risk of preterm labor. ScienceDaily. Retrieved April 17, 2014 from www.sciencedaily.com/releases/2010/02/100204075029.htm
NIH/National Institute of Child Health and Human Development. "Genes of pregnant women and their fetuses can increase risk of preterm labor." ScienceDaily. www.sciencedaily.com/releases/2010/02/100204075029.htm (accessed April 17, 2014).

Share This



More Health & Medicine News

Thursday, April 17, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Could Even Casual Marijuana Use Alter Your Brain?

Could Even Casual Marijuana Use Alter Your Brain?

Newsy (Apr. 16, 2014) A new study conducted by researchers at Northwestern and Harvard suggests even casual marijuana use can alter your brain. Video provided by Newsy
Powered by NewsLook.com
Thousands Of Vials Of SARS Virus Go Missing

Thousands Of Vials Of SARS Virus Go Missing

Newsy (Apr. 16, 2014) A research institute in Paris somehow misplaced more than 2,000 vials of the deadly SARS virus. Video provided by Newsy
Powered by NewsLook.com
Formerly Conjoined Twins Released From Dallas Hospital

Formerly Conjoined Twins Released From Dallas Hospital

Newsy (Apr. 16, 2014) Conjoined twins Emmett and Owen Ezell were separated by doctors in August. Now, nearly nine months later, they're being released from the hospital. Video provided by Newsy
Powered by NewsLook.com
Ebola Outbreak Now Linked To 121 Deaths

Ebola Outbreak Now Linked To 121 Deaths

Newsy (Apr. 15, 2014) The ebola virus outbreak in West Africa is now linked to 121 deaths. Health officials fear the virus will continue to spread in urban areas. 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