(Press-News.org) The risk of preterm delivery increases with maternal overweight and obesity, according to a new Swedish study published in Journal of the American Medical Association (JAMA). Women with the highest Body Mass Index (BMI) also had the highest statistical risk of giving preterm birth – and especially extremely preterm birth.
"For the individual woman who is overweight or obese, the risk of an extremely preterm delivery is still small", says Dr. Sven Cnattingius, Professor at Karolinska Institutet in Sweden, who led the study. "However, these finding are important from a population perspective. Preterm infants and, above all, extremely preterm infants account for a substantial fraction of infant mortality and morbidity in high income countries."
In the JAMA study, Dr. Cnattingius and colleagues at Karolinska Institutet and the University of Michigan, U.S., used information from 1.5 million singleton deliveries included in the population-based Swedish Medical Birth Register from 1992 through 2010. Information about maternal weight at first visit to prenatal care and height was used to calculate women's BMI, defined as weight in kilograms divided by height in square meters. A BMI between 18.5 and 24.9 was assessed as normal, 25 to 29.9 as overweight, and a BMI of 30 or more as obesity. Among young Swedish women of normal length (167 cm), a weight from 70 to 83 kilograms is considered overweight and more than 83 kilograms is considered obesity.
Compared to women of normal weight, overweight women had a 25 percent increased risk of extremely preterm delivery. Women with mild obesity had a 60 percent increased risk of giving birth extremely preterm. For women with severe obesity (BMI 35-39.9) or extreme obesity (BMI 40 or more) the corresponding risk was doubled and tripled, respectively. Risks of very and moderately preterm deliveries also increased with BMI.
"34 percent of all pregnant women in Sweden are either overweight or obese, and this impacts the number of preterm born infants", says Dr. Cnattingius. "Overweight and obesity also increase the risk of maternal pregnancy complications, including preeclampsia, gestational diabetes, and Cesarean delivery."
In Sweden, there are annually around 100,000 childbirths. Of these children, around 250 are born extremely preterm (more than 12 weeks before expected date), 500 very preterm (8 to 12 weeks too early) and 4,500 moderately preterm (4 to 8 weeks too early).
Researchers found that the overweight and obesity related risk of medically indicated preterm delivery was substantially explained by increased risks of obesity-related diseases. Above all, the severe pregnancy complication preeclampsia justified the need of medically indicated preterm delivery due to concern of maternal and infant health. The overweight and obesity related risk of spontaneous preterm delivery was primarily confined to extremely preterm delivery.
Infection and inflammation are considered main risk factors for spontaneous extremely preterm delivery with a spontaneous onset, and maternal obesity is associated with increased production of inflammatory proteins. The researchers hypothesize that the increased inflammatory state in obese women may make them more susceptible to infections, which may increase their risk of spontaneous extremely preterm delivery.
###
The study was funded with a Distinguished Professor Award from Karolinska Institutet to Sven Cnattingius.
Publication: 'Maternal obesity and risk of preterm delivery', Cnattingius S, Villamor E, Johansson S, Bonamy A-K, Persson M, Wikström A-K, Granath F, JAMA, June 12 – 2013, Vol 309, No 22. Embargoed until Tuesday 11 June 2013 at 22:00 CET / 21:00 UK Time / 4 p.m. U.S. Eastern Time.
Journal website: jama.jamanetwork.com
For further information, please contact:
Professor Sven Cnattingius
Department of Medicine, Solna
Karolinska Institutet
Tel.: +46 (0)8-51776181 or +46 (0)76-2820997
E-mail: sven.cnattingius@ki.se
Contact the Press Office and download images: ki.se/pressroom
Karolinska Institutet – a medical university: ki.se/english
Obesity increases the risk of preterm delivery
2013-06-12
ELSE PRESS RELEASES FROM THIS DATE:
Training and advising pediatricians in antibiotic usage improves compliance with Rx guidelines
2013-06-12
As disease-causing microbes continue their worrisome trend of developing resistance to commonly used antibiotics, public health experts have called for more selective use of those medicines. A new study suggests that educating pediatricians in their offices, and auditing their prescription patterns, encourages them to choose more appropriate antibiotics for children with common respiratory infections.
"Although much research has focused on improving how hospitals use antibiotics, there have been few studies of interventions in outpatient settings, where the vast majority ...
Sleep apnea increases risk of sudden cardiac death
2013-06-12
A moderate case of obstructive sleep apnea can significantly increase a person's risk for sudden cardiac death, an often fatal condition where the heart stops beating and must be immediately treated with CPR or an automated external defibrillator, according to the largest study of its kind published online today in the Journal of the American College of Cardiology.
Sleep apnea is diagnosed when a person stops breathing for 10 seconds or longer at least five times per hour during sleep. Symptoms can include loud snoring, choking or gasping during sleep, and morning drowsiness. ...
Younger mothers and older mothers are at higher risk of adverse delivery outcomes
2013-06-12
Younger mothers are at a higher risk of preterm birth while older mothers are more likely to have a caesarean section, suggests a new study published today (12 June) in BJOG: An International Journal of Obstetrics and Gynaecology.
The study, conducted over a 12-year period (2000-2011) in Ireland, examined the delivery outcomes of 36,916 first-time mothers at varying maternal ages.
The pregnant women were subdivided into five age groups, 3.3% at 17 years or younger (17-), 7.2% at 18-19 years, 77.9% at 20-34 years, 9.9% at 35-39 years and 1.7% at 40 years or older (40+). ...
New research links body clocks to osteoarthritis
2013-06-12
Scheduled exercise, regular meals and the periodic warming and cooling of joints could be used to relieve the symptoms of osteoarthritis according to scientists at The University of Manchester. Their research may also help explain why older people are more prone to developing this common joint disorder.
The team in the Faculty of Life Sciences has established for the first time that cartilage cells have a functioning body clock that switches on and off genes controlling tissue function. The rhythm of the cartilage clock perhaps goes some way to explain why osteoarthritis ...
X-rays reveal new picture of 'dinobird' plumage patterns
2013-06-12
The findings came from X-ray experiments by a team from The University of Manchester, working with colleagues at the US Department of Energy's (DOE) SLAC National Accelerator Laboratory. The scientists were able to find chemical traces of the original 'dinobird' and dilute traces of plumage pigments in the 150 million-year-old fossil.
"This is a big leap forward in our understanding of the evolution of plumage and also the preservation of feathers," said Dr Phil Manning, a palaeontologist at The University of Manchester and lead author of the report in the June 13 issue ...
Experimental vaccine shows promise against TB meningitis
2013-06-12
A team of Johns Hopkins researchers working with animals has developed a vaccine that prevents the virulent TB bacterium from invading the brain and causing the highly lethal condition TB meningitis, a disease that disproportionately occurs in TB-infected children and in adults with compromised immune system.
A report on the federally funded research is published online June 11 in the journal PLOS ONE.
TB brain infections often cause serious brain damage and death even when recognized and treated promptly, researchers say. This is so because many drugs currently used ...
Perfect pitch may not be absolute after all
2013-06-12
VIDEO:
University of Chicago researchers found that people's concept of what perfect pitch is can be changed, a discovery that underscores the malleability of the brain.
Click here for more information.
People who think they have perfect pitch may not be as in tune as they think, according to a new University of Chicago study in which people failed to notice a gradual change in pitch while listening to music.
When tested afterward, people with perfect, or absolute pitch, thought ...
Polymer structures serve as 'nanoreactors' for nanocrystals with uniform sizes, shapes
2013-06-12
Using star-shaped block co-polymer structures as tiny reaction vessels, researchers have developed an improved technique for producing nanocrystals with consistent sizes, compositions and architectures – including metallic, ferroelectric, magnetic, semiconductor and luminescent nanocrystals. The technique relies on the length of polymer molecules and the ratio of two solvents to control the size and uniformity of colloidal nanocrystals.
The technique could facilitate the use of nanoparticles for optical, electrical, optoelectronic, magnetic, catalysis and other applications ...
1 in 6 women at fracture clinics report domestic violence
2013-06-12
HAMILTON, ON (June 11, 2013) -- One in six women arriving at orthopedic fracture clinics have been victims of physical, emotional, or sexual violence at the hands of an intimate partner within the past year, and one in 50 arrive as a direct result of intimate partner violence (IPV), according to the largest multinational study of its kind to date, led by McMaster University researchers.
The report has been published on Online First by The Lancet.
"The unexpectedly high rate of IPV in orthopedics suggests that injury clinics are the ideal location for identification ...
Scientists identify thousands of plant genes activated by ethylene gas
2013-06-12
LA JOLLA — It's common wisdom that one rotten apple in a barrel spoils all the other apples, and that an apple ripens a green banana if they are put together in a paper bag. Ways to ripen, or spoil, fruit have been known for thousands of years—as the Bible can attest—but now the genes underlying these phenomena of nature have been revealed.
In the online journal eLIFE, a large international group of scientists, led by investigators at the Salk Institute for Biological Studies, have traced the thousands of genes in a plant that are activated once ethylene, a gas that ...