Parenting Bulletin    
Recent News |  Archives |  Tags |  Newsletter |  Message Board/Forum |  About |  Links |  Subscribe to ParentingBulletin.com RSS Feed Subscribe


More Articles
Improvements in fuel cell designImprovements in fuel cell design

Rediscovering Venus to find faraway earths

Archaeologists discover bronze remains of Iron Age chariot

Researchers resolve the Karakoram glacier anomaly, a cold case of climate science

Fish tale: New study evaluates antibiotic content in farm-raised fishFish tale: New study evaluates antibiotic content in farm-raised fish

New 3-D display technology promises greater energy efficiencyNew 3-D display technology promises greater energy efficiency

Researchers break nano barrier to engineer the first protein microfiberResearchers break nano barrier to engineer the first protein microfiber

Magnetic mirrors enable new technologies by reflecting light in uncanny ways

Structure of an iron-transport protein revealedStructure of an iron-transport protein revealed

First step: From human cells to tissue-engineered esophagusFirst step: From human cells to tissue-engineered esophagus

Lift weights, improve your memory

Spiders: Survival of the fittest group

Autophagy helps fast track stem cell activationAutophagy helps fast track stem cell activation

Myelin vital for learning new practical skillsMyelin vital for learning new practical skills

More physical activity improved school performanceMore physical activity improved school performance

Around the world in 400,000 years: The journey of the red foxAround the world in 400,000 years: The journey of the red fox

Engineering new vehicle powertrainsEngineering new vehicle powertrains

Active aging is much more than exerciseActive aging is much more than exercise

Study: New device can slow, reverse heart failureStudy: New device can slow, reverse heart failure

Are the world's religions ready for ET?Are the world's religions ready for ET?

Gut bacteria, artificial sweeteners and glucose intoleranceGut bacteria, artificial sweeteners and glucose intolerance

Recreating the stripe patterns found in animals by engineering synthetic gene networksRecreating the stripe patterns found in animals by engineering synthetic gene networks

Laying the groundwork for data-driven scienceLaying the groundwork for data-driven science

Nature's designs inspire research into new light-based technologiesNature's designs inspire research into new light-based technologies

Missing piece found to help solve concussion puzzleMissing piece found to help solve concussion puzzle

Biologists delay the aging process by 'remote control'Biologists delay the aging process by 'remote control'

Geography matters: Model predicts how local 'shocks' influence U.S. economyGeography matters: Model predicts how local 'shocks' influence U.S. economy

Identified for the first time what kind of explosive has been used after the detonationIdentified for the first time what kind of explosive has been used after the detonation

Copied from nature: Detecting software errors via genetic algorithmsCopied from nature: Detecting software errors via genetic algorithms

Stress in early pregnancy can lead to shorter pregnancies, more pre-term births and fewer baby boys (12/15/2011)

<
Tags:
preemies

Stress in the second and third months of pregnancy can shorten pregnancies, increase the risk of pre-term births and may affect the ratio of boys to girls being born, leading to a decline in male babies. These are the conclusions of a study that investigated the effect on pregnant women of the stress caused by the 2005 Tarapaca earthquake in Chile.

Although it has been known for a while that stress may affect the duration of pregnancy, until now, no study has looked at the impact of both the timing of the stress and the effect that stress might have on the ratio of male-to-female births. The research published online in Europe's leading reproductive medicine journal Human Reproduction [1] today (Thursday), provides answers to these questions and also suggests that it is exposure to stress itself rather than other factors that can often accompany or cause stress, such as poverty, that appears to affect pregnancy.

Professors Florencia Torche (PhD) and Karine Kleinhaus (MD, MPH), of New York University (New York, USA), analysed birth certificates of all babies born between 2004-2006 in Chile; there were over 200,000 births a year. The birth records provided information on gestational age at delivery, sex, weight and height of the baby and whether any medical attention was required. They also included information on the mother's age, marital status, whether or not she had been pregnant before and in which of the 350 counties in Chile she lived. This information gave the researchers very specific information about how exposed the mothers were to the effects of the earthquake, based on how close they lived to the epicentre.

"Looking at information on gestational age at the time of the earthquake in a large, unselected group of women, enabled us to determine the risk for specific birth outcomes by gestational age of exposure to a stressor, which, because it was a natural disaster, was experienced by all at the same time, although in varying degrees of severity, depending on how close they lived to the epicentre," said Prof Torche who is Associate Professor of Sociology. "We were able to capture the developmental periods in which exposure to stress was most detrimental for either sex."

The earthquake measured 7.9 on the moment-magnitude scale (the successor to the Richter scale), which is classified as "disastrous". The areas most affected were the cities of Iquique and Alto Hospicio, and the surrounding towns. The researchers found that women who experienced a severe quake (because they lived closest) during their second and third months of pregnancy had shorter pregnancies and were at higher risk of delivering pre-term (before 37 weeks gestation). The pregnancies of women exposed to the earthquake in the second month of pregnancy were on average 0.17 weeks (1.3 days) shorter than those in the unaffected areas of Chile. The pregnancies of those exposed in the third month were 0.27 weeks (1.9 days) shorter. Normally, about six in 100 women had a pre-term birth, but among women exposed to the earthquake in the third month of pregnancy, this rose by 3.4%, meaning more than nine women in 100 delivered their babies early.

The effect was most pronounced for female births; the probability of pre-term birth increased by 3.8% if exposure to the quake occurred in the third month, and 3.9% if it occurred in the second month. In contrast there was no statistically significant effect seen in male births.

As the stress of the earthquake had greater effect on pre-term births in girls rather than boys, the researchers had to make adjustments for this when calculating the effect of stress on the sex ratio: the ratio of male to female live births. They found that there was a decline in the sex ratio among those exposed to the earthquake in the third month of gestation of 5.8%.

Prof Kleinhaus, who is Assistant Professor of Psychiatry, Obstetrics & Gynecology, and Environmental Medicine, explained: "Generally, there are more male than female live births. The ratio of male to female births is approximately 51:49 - in other words, out of every 100 births, 51 will be boys. Our findings indicate a 5.8% decline in this proportion, which would translate into a ratio of 45 male births per 100 births, so that there are now more female than male births. This is a significant change for this type of measure."

Previous research has suggested that in times of stress women are more likely to miscarry male foetuses because they grow larger than females and therefore require greater investment of resources by the mother; they may also be less robust than females and may not adapt their development to a stressful environment in the womb. "Our findings on a decreased sex ratio support this hypothesis and suggest that stress may affect the viability of male births," said Prof Torche. "In contrast, among female conceptions, stress exposure appears not to affect the viability of the conception but rather, the length of gestation."

The researchers suggest that possible mechanisms to explain their findings could involve the placenta, which sets the duration of the pregnancy, and the effect of the stress hormone cortisol on the placenta's function.

Prof Torche concluded: "In terms of implications, it is clearly unrealistic to recommend avoiding natural disasters. However, this research suggests the need to improve access to healthcare for women from the onset of pregnancy and even before conception. Obviously this will not reduce the exposure to stress, but it may provide care, advice, and tools that would allow women to cope with stressful circumstances.

"A separate implication has to do with our ability to use a 'natural experiment' (the earthquake) to isolate the effect of stress from factors that commonly go with it. In particular, researchers have long suggested that poverty is bad for health outcomes because of the stress it elicits. This is very plausible, but it is difficult to disentangle the effect of stress alone from the effect of other factors associated with poverty, such as nutritional deprivation and poor housing, which could also have an independent impact on women's health and the outcome of their pregnancies. This makes it difficult to ascertain whether stress itself does, indeed, matter. Our research provides strong evidence that it does."

Note: This story has been adapted from a news release issued by the European Society of Human Reproduction and Embryology

Post Comments:

Search
New Articles
Certain parenting tactics could lead to materialistic attitudes in adulthoodCertain parenting tactics could lead to materialistic attitudes in adulthood

Even expectant dads experience prenatal hormone changes

A 2-minute delay in cutting the umbilical cord leads to a better development of newborns

Study finds low weight gain in pregnant women reduces male fetal survivalStudy finds low weight gain in pregnant women reduces male fetal survival

Prenatal exposure to common household chemicals linked with substantial drop in child IQ

Are you helping your toddler's aggressive behavior?

Punishing kids for lying just doesn't work

Higher birth weight indicates better performance in school

Are the benefits of breast milk stimulant worth the risk?

Many chest X-rays in children are unnecessaryMany chest X-rays in children are unnecessary

Why does physical activity during childhood matter?

Heavier newborns show academic edge in school

Why don't children belong to the clean plate club?Why don't children belong to the clean plate club?

New study examines the effect of timing of folic acid supplementation during pregnancy

Full-day preschool linked with increased school readiness compared with part-day



Archives
December 2014
November 2014
October 2014
September 2014
August 2014
July 2014
June 2014
May 2014
April 2014
March 2014
February 2014
January 2014
December 2013
November 2013
October 2013
September 2013
August 2013
July 2013
June 2013
May 2013
April 2013
March 2013
February 2013
January 2013
December 2012
November 2012
October 2012
September 2012
August 2012
July 2012
June 2012
May 2012
April 2012
March 2012
February 2012
January 2012
December 2011
November 2011
October 2011
September 2011
August 2011
July 2011
June 2011
May 2011
April 2011
March 2011
February 2011
January 2011
December 2010
November 2010
October 2010
September 2010
August 2010
July 2010
June 2010
May 2010
April 2010
March 2010




Science Friends
Agricultural Science
Astronomy News
Biology News
Biomimicry Science
Cognitive Research
Chemistry News
Tissue Engineering
Cancer Research
Cybernetics Research
Electonics Research
Forensics Report
Fossil News
Genetic Archaeology
Genetics News
Geology News
Nanotech News
Microbiology Research
Physics News
  Archives |  Submit News |  Advertise With Us |  Contact Us |  Links
Use of this site constitutes acceptance of our Terms of Service and Privacy Policy. All contents © 2000 - 2019 ParentingBulletin.com. All rights reserved.