Washington, June 09: Babies born just 1 or 2 weeks before their 40-week gestation due date are more likely to develop learning difficulties such as autism or dyslexia, according to a British study published on Tuesday.
The findings show that even babies born at 39 weeks — the point at which many women who choose to have a Caesarean section delivery — have an increased risk of a developing a learning disability compared with babies born a week later at 40 weeks.
Scientists in Scotland, analysing the birth history of more than 400,000 schoolchildren, found that while babies born at 40 weeks have a 4 percent risk of learning difficulties, those born at 37 to 39 weeks of gestation have a 5.1 percent risk.
“There was an increasing risk of special educational needs as the gestation date fell, so as deliveries got earlier, the risk went up,” said Jill Pell, an expert in public health and health policy Glasgow University, who led the study.
“Even being just a week early put the risk up.”
It is already known that a baby born prematurely — for example at 24 weeks of gestation — is more likely to have learning difficulties. But the risks for babies born in the 24 to 40 week range had not previously been studied.
According to the World Health Organisation, more and more women worldwide are delivering by caesarean section and a “significant proportion” of these surgical procedures are performed without any clear medical need.
Around a third of babies are born between 37 and 39 weeks of gestation, either by caesarean section or natural vaginal delivery.
Rates of autism have also been rising, with worldwide prevalence estimated at between 1 to 2 people in every thousand, although experts say this may be partly due to better diagnosis.
Pell noted this rise but said it would be “a leap too far” to link her findings directly to rates of autism, since autism was only one of a range of learning difficulties considered.
Pell, whose study was published in the Public Library of Science Medicine journal, stressed that caesarean sections were not the only factor behind early-term births, since some women go into labour naturally before 40 weeks of gestation.
But she said doctors and women should consider the risks of learning difficulties when thinking about a caesarean.
“It is now normal policy (in caesarean section) to deliver women a week early,” she said in a telephone interview. “But if you make a decision…for an elective pre-term delivery, then it has to be a balance, weighing up the risks and potential benefits.
“What this study shows is that special education needs are another factor that need to be considered.”
Children with special educational needs may have either a learning difficulty such as dyslexia or autism, or a physical difficulty such as deafness or poor vision.
Pell found that although the risk of educational difficulties was much higher in preterm than in early term babies, the absolute numbers of children with difficulties in the 37 to 39 week group were higher, because many more babies are born at this time than before 37 weeks.
In her study, early term births accounted for 5.5 percent of cases learning disabilities, while preterm deliveries accounted for only 3.6 percent of cases. (Editing by Mark Heinrich) REUTERS
Scientists warn of oil spill kill zone in the deep by Juan Castro Olivera (PICTURE)
MIAMI, June 8, 2010 (AFP) – Huge plumes of crude from the Gulf of Mexico oil spill are hovering in the ocean depths, silently spreading their poison and slowly devastating the underwater ecosystem, scientists warned Tuesday.
“Water samples taken by our research vessel in the area and analyzed by our experts and chemical oceanographers show large portions of oil deep in the ocean from 50 meters (yards) down to 1400 meters,” University of South Florida (USF) oceanographer Yonggang Liu told AFP.
“That oil in deep water is invisible to satellites,” said Liu, who is taking part in a multi-disciplinary team of experts tracking the BP oil spill both at the surface and beneath the Gulf of Mexico.
Just because the oil is hidden from view doesn’t make it any less toxic to the environment, scientists said. On the contrary, it makes it practically impossible to clean up and render harmless.
“You don’t need more than logical thinking to see that the ecosystem in the deep waters of the Gulf will be affected. This would impact greatly the whole food chain, in lots of fishes that are sensitive and in the small creatures of the ocean,” Liu said.
Despite the warnings, BP maintains the oil spill is spreading mostly on the surface of the Gulf, but that claim does not seem to be bourne out by research.
“The data speaks for itself,” National Oceanic and Atmospheric Administration (NOAA) official Steven Murawski told a joint press conference with USF scientists on the team’s observations in the Gulf.
Samples taken by USF research ships at three sites northeast and southeast of the oil gusher up to a depth of one mile (1.6 kilometers) and off the coast of Louisiana show low concentrations of oil across all depths, the experts said.
Suspended in ocean water, oil pollution poses a serious threat to floating plankton, as well as to marine plants and animals living at the bottom, including deep-sea corals, said scientists from University of Miami (UM) Division of Marine Geology and Geophysics.
They said ocean water either stops the oil from rising to the surface or slows it down considerably, meaning that some of the oil mixed with dispersants BP uses to break up the spill, will never reach the surface where it can biodegrade faster.
“The deep-water communities within the Gulf of Mexico and in the Straits of Florida are well hidden from us, but they include many species of cold-water corals that live at depths of 600-1500 meters (1,969-4,921 feet) in waters as cold as 3.0 degrees Celsius (37.4 Fahrenheit),” said UM scientist Gregor Eberli.
“It is most likely that the delicate cold-water corals are not able to digest these oil-laden food particles and will perish in large numbers,” he added.
“Particularly vulnerable to disturbance are deep-sea fish that form part of this ecosystem because of their late maturation, extreme longevity, low fecundity and slow growth,” Eberli said.
National disaster coordinator, Coast Guard Admiral Thad Allen, warned Monday of the long-term environmental and ecological effects of the slick, which has broken into thousands of ribbons threatening shores from Louisiana to Florida.
“Dealing with the oil spill on the surface will go on for a couple of months,” Allen said.
“Long-term issues of restoring environments and habitats and stuff will be years.”
–Agencies