Nap Nanny seats made by Baby Matters LLC of Berwyn, Pa., pose a 'substantial risk of injury and death to infants,' the Consumer Product Safety Commission said.

Four national retailers agreed to recall more than 150,000 Nap Nanny baby recliners after at least five infant deaths and dozens of reports of children nearly falling out of the recliners, the Consumer Product Safety Commission said Thursday.

The recall covers Nap Nanny Generations One and Two, and the Chill model infant recliners. All were sold between 2009 and 2012. The Nap Nanny was designed to mimic the curves of a baby car seat, elevating an infant slightly to help reduce reflux, gas, stuffiness or other problems.

The CPSC warned parents and caregivers that the Nap Nanny contains defects in its design, warnings and instructions. The agency said the product poses a substantial risk of injury and death to infants.

The four retailers — Amazon.com, Buy Buy Baby, Diapers.com and Toys R Us/Babies R Us — agreed to voluntarily participate in the recall of the Nap Nanny because its manufacturer is unable or unwilling to participate, the government agency said in a statement.

The manufacturer, Baby Matters LLC of Berwyn, Pa., told The Associated Press earlier this month that it had gone out of business. At the time, the company's website carried a statement from owner and founder Leslie Gudel that the company didn't believe the CPSC complaint had merit and that its products were safe when used as instructed.

The first two versions of the foam recliner were recalled in July 2010 after the agency became aware of one death and 22 reports of infants hanging out or falling over the side of the Nap Nanny even though most of the infants had been placed in the recliner's harness. Since then, the agency learned of four more deaths. Four were linked to the first versions of the recliner, and one to the newer model.

Five thousand Nap Nanny Generation One and 50,000 Generation Two models were sold between 2009 and early 2012. About 100,000 Chill models have been sold since January 2011.

The CPSC advised consumers seeking more information about the recall to review the return policies of the retailers participating in the recall.

Related:

• Baby deaths prompt CPSC to sue Nap Nanny maker

More from NBCNews.com health:

• Conjoined twin girls successfully separated
• Obesity declining in young, poorer kids
  

Marijuana (cannabis) use may be linked to the development of psychotic symptoms in teens -- but the reverse could also be true: psychosis in adolescents may be linked to later pot use, according to a new Dutch study.

"We have focused mainly on temporal order; is it the chicken or the egg? As the study shows, it is a bidirectional relationship," wrote the study's lead author Merel Griffith-Lendering, a doctoral candidate at Leiden University in The Netherlands, in an email to Reuters Health.

Previous research established links between marijuana and psychosis, but scientists questioned whether pot use increased the risk of mental illness, or whether people were using pot to ease their psychotic symptoms, such as hallucinations and delusions.

"What is interesting in this study is that both processes are going on at the same time," said Dr. Gregory Seeger, medical director for addiction services at Rochester General Hospital in upstate New York.

He told Reuters Health that researchers have been especially concerned about what tetrahydrocannabinol (THC), the active property in pot, could do to a teenager's growing brain.

"That's a very vulnerable period of time for brain development," and individuals with a family history of schizophrenia and psychosis seem to be more sensitive to the toxic effects of THC, he said.

A 2010 study of 3,800 Australian teenagers found that those who used marijuana were twice as likely to develop psychosis compared to teens who never smoked pot.

But that study also found that those who suffered from hallucinations and delusions when they were younger were also more likely to use pot early on. 

Chicken v. egg 

For the new study, published in the journal Addiction, the researchers wanted to see which came first: pot or psychosis.

Griffith-Lendering and her colleagues used information on 2,120 Dutch teenagers, who were surveyed about their pot use when they were about 14, 16 and 19 years old.

The teens also took psychosis vulnerability tests that asked - among other things - about their ability to concentrate, their feelings of loneliness and whether they see things other people don't.

Overall, the researchers found 940 teens, or about 44 percent, reported smoking pot, and there was a bidirectional link between pot use and psychosis.

For example, using pot at 16 years-old was linked to psychotic symptoms three years later, and psychotic symptoms at age 16 were linked to pot use at age 19.

This was true even when the researchers accounted for mental illness in the kids' families, alcohol use and tobacco use.

Griffith-Lendering said she could not say how much more likely young pot users were to exhibit psychotic symptoms later on.

Also, the new study cannot prove one causes the other. Genetics may also explain the link between pot use and psychosis, said Griffith-Lendering.

"We can say for some people that cannabis comes first and psychosis comes second, but for some people they have some (undiagnosed) psychosis (and) perhaps cannabis makes them feel better," said Dr. Marta Di Forti, of King's College, London, who was not involved with the new research.

Di Forti, who has studied the link between pot and psychosis, told Reuters Health she considers pot a risk factor for psychosis - not a cause.

Seeger, who was also not involved with the new study, said that there needs to be more public awareness of the connection.

"I think the marijuana is not a harmless substance. Especially for teenagers, there should be more of a public health message out there that marijuana has a public health risk," he said.

Griffith-Lendering agrees.

"Given the severity and impact of psychotic disorders, prevention programs should take this information into consideration," she said.

More from NBCNews.com health:

Reports of shattering pans on the rise

'Dystextia': Gibberish texts sound stroke alarm

Playing hard-to-get actually works, study shows

A mercury-containing preservative should not be banned as an ingredient in vaccines, U.S. pediatricians said Monday, in a move that may be controversial.

In its statement, the American Academy of Pediatrics (AAP) endorsed calls from a World Health Organization (WHO) committee that the preservative, thimerosal, not be considered a hazardous source of mercury that could be banned by the United Nations.

Back in 1999, a concern that kids receiving multiple shots containing thimerosal might get too much mercury - and develop autism or other neurodevelopmental problems as a result - led the AAP to call for its removal, despite the lack of hard evidence at the time.

"It was absolutely a matter of precaution because of the absence of more information," said Dr. Louis Cooper, from Columbia University in New York, who was on the organization's board of directors at the time.

"Subsequently an awful lot of effort has been put into trying to sort out whether thimerosal causes any harm to kids, and the bottom line is basically, it doesn't look as if it does," Cooper, who wrote a commentary published with the AAP's statement, told Reuters Health.

In a 2004 safety review, for example, the independent U.S. Institute of Medicine concluded there was no evidence thimerosal-containing vaccines could cause autism. A study from the Centers for Disease Control and Prevention came to the same conclusion in 2010.

With the exception of some types of flu shots, the compound is not used in vaccines in the United States, which are distributed in single-dose vials.

And nobody is arguing that should change, according to Dr. Walter Orenstein, a member of the AAP Committee on Infectious Diseases and a researcher at the Emory Vaccine Center in Atlanta.

But in countries with fewer resources - where many children still die of vaccine-preventable diseases - it's cheaper and easier to use multi-dose vials of vaccines against diphtheria and tetanus, for example.

Thimerosal prevents the rest of a multi-dose vial from getting contaminated with bacteria or fungi each time a dose is used.

Researchers estimated it could cost anywhere from two to five times as much to manufacture vaccines for developing countries without thimerosal, and both transporting vaccines and keeping them refrigerated would be much harder as well.

"If we had to take the thimerosal out of those multi-dose vials, we're having a hard time completing the task of getting every kid immunized now, that would add a tremendous burden," Cooper said - and more children would probably die as a result.

"Children who can now be protected from these life-threatening diseases could become vulnerable," Orenstein told Reuters Health.

The new statement is published in the AAP's journal Pediatrics.

Thimerosal contains a type of mercury called ethyl mercury. Toxic effects have been tied to its cousin, methyl mercury, which stays in the body for much longer.

Earlier this year, the WHO said replacing thimerosal with an alternative preservative could affect vaccine safety and might cause some vaccines to become unavailable.

Mercury, however, is still on the list of global health hazards to be banned in a draft treaty from the United Nations Environment Program - which would mean a ban on thimerosal.

Reducing mercury exposure "is a wonderful thing," Orenstein said.

However, "We need this exception because thimerosal is so vital for protecting children."

He said keeping thimerosal in vaccines is essential mostly for humanitarian reasons - although preventing childhood diseases in the developing world could also help the U.S. because other countries can serve as reservoirs for illness.

"For American parents, this is more looking at the world and our role and responsibility in protecting the children of the world than it is a direct impact," Orenstein said.

More health news from NBCNews.com:

Can exercise detox your body? It's not about the sweat

Running burns more fat than weights, study finds

Beyond picky eaters: When your child is too thin

For all the miracle stories of tiny preemies who survive, the sad reality is that scientists know far too little about what triggers premature birth and how to prevent it. And despite some recent progress, the U.S. has a far higher rate of preterm births than other similar nations.

On Thursday, an international coalition said there are a handful of proven protections — and if the U.S. and other developed countries do a better job of using them, together they could keep 58,000 babies a year from being born too soon.

That's a blip in the global epidemic of prematurity: About 15 million preterm babies are born every year, most of them in Africa and parts of Asia where the priority is to improve care of these fragile newborns. More than 1 million premature infants die, mostly in developing countries, and survivors can suffer lifelong disabilities.

But in wealthier countries, where sophisticated medical care already keeps most preemies alive, the focus is shifting to how to prevent these births in the first place. Nearly 1 in 10 births across the developed world are preterm, and about 1 in 8 in the U.S. Only recently have rates begun leveling off or dropping in many of these countries after years of steady increases.

Thursday's report makes clear just how hard additional progress on that front will be — projecting an average 5 percent drop in preterm birth rates across the highest-income countries by 2015, if they follow the new advice.

"Shockingly, very little reduction is currently possible," specialists with the World Health Organization, Save the Children, U.S. National Institutes of Health, March of Dimes and other groups reported in The Lancet.

But even that improvement would translate into about $3 billion in annual savings from medical bills and lost productivity, the group calculated. Nearly half that savings would be in the U.S.

The bigger message: It's time for a major scientific push to figure out the causes of preterm birth and find some better ways to intervene.

"I don't think it's hopeless at all," said report co-author Dr. Catherine Spong, a maternal-fetal medicine specialist at NIH who points to clues that infections and inflammation affecting the mother play a yet-to-be-understood role.

Because healthier babies grow into healthier adults, "if you could improve pregnancy outcomes, you could improve the health of the nation, quite honestly," she added.

Over half a million U.S. babies are born premature, before completion of the 37th week of pregnancy. That's 11.7 percent of the babies born in 2011, the lowest rate of preterm birth in a decade and down from a peak of 12.8 percent in 2006, the March of Dimes reported earlier this week.

Contrast that with Japan and Sweden, where fewer than 6 percent of births are premature, or Canada and Britain where fewer than 8 percent are.

Last spring, this same international coalition provided the first country-by-country estimates of preterm births and recommended some inexpensive steps that developing countries could take to improve preemie survival. Thursday's follow-up analyzed trends in developed countries, to come up with advice on preventing prematurity.

The report recommends:

• Nearly eliminating the practice of inducing labor and C-sections scheduled much ahead of mom's due date unless they're medically necessary. Much of the recent U.S. improvement comes from reducing elective early deliveries, leading to a drop in "late preemies," babies born a few weeks early. 
• Helping women to quit smoking. Smoking at some point during pregnancy varies widely, from 10 percent in Canada to 23 percent in the U.S. and 30 percent in Spain, the report found. 
• Providing regular injections of the hormone progesterone to certain women at high risk, largely because of a prior preterm birth. A recent NIH survey of obstetricians found just 21 percent of eligible patients received the shots. 
• Putting a stitch into the cervix of certain high-risk women, those who have what's called a short cervix. 
• Using just one embryo, not multiples, when in vitro fertilization is used. 

The impact would vary. The U.S. could see an 8 percent drop in its preterm birth rate by 2015 if it fully implemented these steps, the report estimated, while countries such as Sweden that already have far fewer preemies would see their rates inch down only slightly more, by about 2 percent.

Having one preemie greatly increases the risk for another. Other risk factors include pregnancy before age 17 or over 40, and the mother's own health conditions, such as being underweight or overweight, or having diabetes or high blood pressure. That's why it's so important for women to have good care, not only early in pregnancy, but before they conceive, said the March of Dimes' Christopher Howson.

But all those factors explain only a portion of preterm birth. NIH's Spong pointed to efforts to understand how vaginal infections and inflammation may help trigger preterm labor.

Another mystery: Why African-American women are at higher risk, with a preterm birth rate of about 17 percent compared to under 11 percent among white women, Howson said.

Still, many women don't know that there are some protections, said Nikki Fleming of suburban Charlotte, N.C., who benefited from two of the steps recommended in Thursday's report and tries to spread the word.

Fleming's first baby, Lauren, was born at 26 weeks, weighing just over 2 pounds and spending her first five months in the hospital. Fortunately Lauren, now a healthy 8-year-old, fared well. But Fleming's next pregnancy ended in a miscarriage.

Her doctor determined that she would benefit from that cervical stitch as well as the progesterone shots. The result: two healthy full-term babies.

"I appreciate that they didn't treat it like an isolated incident," Fleming said. 

More from NBCNews.com health: 

Therapy can help scared moms avoid C-section

9 kinds of salmonella found in recalled peanut butter

Fungal meningitis outbreak could happen again, FDA warns

BurkeTriolo Productions

A new study on peanut allergies adds support to the "hygiene hypothesis."

By MyHealthNewsDaily staff

Children from wealthy families may more likely to have peanut allergies than those less well-off, a new study finds.

In the study, children ages 1 to 9 from high-income families had higher rates of peanut allergies compared with children these ages from lower income families.

The researchers analyzed information from 8,306 children and adults whose blood samples were taken as part of a national health survey in 2005 to 2006. About 9 percent of participants had an elevated levels of antibodies to peanuts, indicating they had the potential to be allergic to peanuts.

The results add support to the hygiene hypothesis, said study researcher Dr. Sandy Yip, of the U.S. Air Force. The hygiene hypothesis is the idea that living in a cleaner environment may make people's immune systems more sensitive, and increase the prevalence of allergies.

The findings are also inline with those of a study published earlier this year, which found children living in cities were more likely to have food allergies compared with those living in rural areas, which tend to be less expensive than cities.

The study was presented this week at the American College of Allergy, Asthma and Immunology meeting in Anaheim, Calif.

More from MyHealthNewsDaily:

• 9 Weirdest Allergies
• 8 Strange Signs You're Having an Allergic Reaction
• Worst US Cities for Allergies Revealed

Graco is voluntarily recalling its Classic Wood Highchairs after reports of children falling from the chairs, the U.S. Consumer Product Safety Commission announced Tuesday afternoon.

So far, Graco has received 58 reports of the highchair seats loosening or detaching from the base. In nine reported cases, children have fallen from the highchairs as the seat separated from the base of the chair. The kids have suffered bumps, bruises and scratches, and at least one child in Canada suffered a concussion as a result of a fall from the highchair. 

About 86,000 highchairs in the U.S. and 3,400 in Canada are being recalled by Graco, in cooperation with the CPSC and Health Canada. 

If you own one of these chairs, stop using it immediately. (It's also illegal to resell or attempt to resell a recalled consumer product, the release from the CPSC reminds.) 

Here's more important information on the recall from the CPSC:

Description: This recall involves all Graco brand Classic Wood Highchairs sold in three wood finishes. The high chair has a top seat, bottom leg assembly and removable tray. The high chair is sold with a beige fabric seat cover. Model number 3C00BPN, 3C00BPN TC, 3C00CHY, 3C00CHY TC, 3C00CPO or 3C00CPO TC is printed on a label on the underside of the seat assembly.

Sold at: Babies R Us, Burlington Coat Factory and other retail stores nationwide and at Target.com and Walmart.com and other online retailers between September 2007 and December 2010 for about $130.

Manufactured in: China

Remedy: Consumers should immediately stop using the recalled high chairs and contact Graco for a free repair kit.

Consumer Contact: For additional information, contact Graco at (800) 345-4109 between 8 a.m. and 5 p.m. ET Monday through Friday and, or visit the firm's website at www.gracobaby.com

More from Vitals:

Front line for meningitis outbreak - the ER

NBC News

More than 6,000 children are injured by spray bottles each year.

Rachael Rettner, MyHealthNewsDaily 

A new type of spray bottle could prevent the thousands of chemical injuries that occur yearly when children get their hands on household cleaners and accidentally spray themselves, its inventors say.

The child-proof spray bottle has not only a forward-facing trigger under the nozzle — as do other spray bottles — but also has a second trigger, jetting out from the back. Both triggers must be pressed for the liquid to be dispensed.

Adult hands are big enough to squeeze both triggers at once, but children's hands are not, said Lara McKenzie, a researcher at Nationwide Children’s Hospital in Ohio who was involved in creating the new design.

While some spray bottles have nozzles that turn and function as on/off switches, children can manipulate these nozzles, McKenzie said.

The new bottle could prevent the 6,000 childhood injuries involving spray bottles each year, she added.

McKenzie and her colleagues had conducted a study on the injuries from household cleaners that send children to the emergency department. The study showed that, while injuries from all household cleaners decreased 46 percent over the last 20 years, injuries from spray bottles remained constant.

In fact, spray bottles were found accountable for about 40 percent of all injuries from household cleaners between 1990 and 2006. The study was published in 2010 in the journal Pediatrics.

The researchers "realized that there were no spray bottles on the market that would be both easy for adults to use and hard for children to get into, so we came up with our own design," McKenzie said. [Watch video: How the spray bottle prevents children's injuries ]

Household cleaners can cause poisoning, chemical burns, dermatitis (swollen, reddened skin) and other injuries. When a spray bottle was involved in a child's injuries, the child was 18 times more likely to have external contact with the chemical (rather than ingestion or inhalation), and 13 times more likely to have eye injuries than other types of injuries, the study found.

McKenzie and colleagues worked with researchers in Ohio State University's departments of design and engineering to come up with the new spray bottle design. After a person releases the triggers, the mechanism "relocks" automatically — there's nothing you have to do to lock it, McKenzie said.

The researchers have filed for a patent on their design and are looking for a partner, such as a spray bottle manufacturer or a cleaning product company, to license their product, McKenzie said.

"We're anxious to see this product on the shelves so we can have an impact and reduce injures and keep kids safe," McKenzie said.

Related content:

• 12 Steps to Prevent Accidental Poisoning
• Top 5 Ways to Reduce Toxins in Homes
• The Old Drug Talk: 7 New Tips for Today's Parents