Staying Well: A Guide to Flu Season When You're Pregnant

During pregnancy, coming down with the flu is riskier than usual. During the 2009 outbreak of H1N1 influenza, for example, pregnant women made up 5 percent of all U.S. deaths due to the virus, despite constituting only about 1 percent of the population at the time.

The risk is greater as pregnancy continues, according to a 2010 paper in the journal JAMA, which found that, of the 56 deaths among pregnant women in the epidemic, 36 of those deaths (64.3 percent) happened in the third trimester. Sixteen, or just over a quarter, of the deaths happened in the second trimester and only four (7 percent) occurred in the first trimester.

Fortunately, there are ways pregnant women can protect themselves from the flu, experts say.

"The [flu] vaccine is the No. 1 priority for any pregnant woman," said Dr. Regan Theiler, the division director of general OB-GYN at Dartmouth-Hitchcock Medical Center in New Hampshire. "It's very effective, and not only does it protect mom, but the antibodies transfer across the placenta and protect the baby for the first six months of life."

Immunity changes

The reasons why the flu is particularly risky for pregnant women aren't entirely understood. Researchers know that a woman's immune system changes in complex ways during pregnancy in order to allow the body to tolerate the fetus, which, after all, is genetically half-alien.

Some of these changes have to do with the placenta, which produces certain molecules to wall off the developing fetus from the mother's immune system.

Other body-wide effects are more complex. For example, a 2014 review in the journal Reproductive Sciences reported that pregnant women have lower numbers of a type of immune cell called dendritic cells circulating in their blood. Dendritic cells capture fragments of invading germs and then present these fragments to other immune cells, which use the information to launch immune responses. Despite this decrease in dendritic cells, some of the fragment-capturing receptors on their surface actually increase, potentially boosting a woman's immune response. In other words, while there are fewer dendritic cells, the ones that are present can capture more germ fragments.

In addition, some pro-inflammatory chemicals that promote inflammation, including molecules called cytokines, also increase. [Flu Shot Facts & Side Effects (Updated for 2016-2017)]

Overall, these factors may promote an increased immune response during pregnancy — and that's not necessarily a great thing. A small 2014 study in the journal PNAS found that pregnant women's immune systems have a stronger natural killer cell and T-cell responses to the flu than nonpregnant women's immune systems do. These two types of immune cells, when supercharged, may actually create extra damage in the pregnant woman's respiratory tract, increasing her risk of developing other problems from the flu, the researchers suggested.

The dangers of flu

A major reason pregnant women who get the flu are at high risk may simply be that their heart and lungs are already taxed, Theiler said.     

Pregnant women "are sort of using all their ability to take in oxygen and move their blood around," she told Live Science.

When the flu virus attacks the cells of the respiratory system, the additional burden may be too much to bear, Theiler said. Death from flu often comes because the virus opens up the opportunity for bacteria to move in, she said, which can lead to pneumonia that, in turn, leads to sepsis, or body-wide inflammation.

In contrast with the Zika virus, which causes mild illness in the mother but can have devastating effects on the developing fetus, the influenza viruses rarely cross the placenta to infect the fetus directly, Theiler said.

Nevertheless, flu has long been linked to increased risks of stillbirth, miscarriage and preterm delivery. A 1961 study in the American Journal of Public Health on 611 pregnant women found that those with a flu infection were more likely to have had a miscarriage, a stillbirth or a preterm delivery than those with no infection (though the number of women uninfected was too low to draw firm statistical conclusions). More recently, a study of a 1989 outbreak of influenza among pregnant women at one medical center in London suggested a link between infection and fetal and newborn mortality. And a 2013 study in The New England Journal of Medicine found that women in Norway who got the flu during pregnancy had nearly twice the risk of losing the baby before birth as women who didn't catch the flu.   

"A healthy mom is a healthy baby," Theiler said.

Preventing the flu

Getting the flu vaccine is the best step a pregnant woman can take to protect herself and her baby, Theiler said. [6 Flu Vaccine Myths]

In 2014, researchers at Dalhousie University in Nova Scotia found, after controlling for other factors, that getting the flu vaccine during pregnancy reduced the risk of preterm birth or giving birth to a low-birth-weight infant. The same New England Journal of Medicine study that found an increased risk of fetal death with flu infection during pregnancy also found that the flu vaccine was very effective, reducing the risk of flu during pregnancy by 70 percent.

Evidence also suggests that the flu vaccine is very safe during pregnancy. A study published Nov. 29 in the journal JAMA Pediatrics looked at a large registry of patients with Kaiser Permanente Northern California and found no evidence that the flu vaccine (or the flu) increased the risk of autism in children.

Nor have researchers found evidence of a heightened risk of adverse effects from the vaccine in pregnant women. A 2011 study in the American Journal of Obstetrics & Gynecology, for example, examined reports submitted to the Vaccines Adverse Event Reporting System, a federal system used to collect information about negative reactions to vaccines. Reports in the database do not have to be confirmed by doctors to be included. The study found no evidence of unusual patterns of adverse events during pregnancy or in infants, the researchers wrote.

Direct comparisons turn up similar results. A 2013 study in the journal Obstetrics & Gynecology compared nearly 76,000 women who received the flu vaccine during pregnancy with almost 150,000 women who didn't and found no increase in adverse effects among the vaccinated women. Another study in the same journal that year used similar data and found no additional risk from vaccination for common pregnancy complications such as high blood pressure, morning sickness or pulmonary embolism.  

Handwashing is the most effective hygiene measure to prevent the flu, Theiler said. Still, if a pregnant women is in close contact with an infected individual — say, an older child — she should call her doctor right away, rather than just relying on handwashing, Theiler added. If the seasonal flu strain isn't well-covered by that year's vaccine, many physicians might want to preemptively treat the woman with anti-viral drugs to ensure she doesn't get sick, because the consequences of infection can be dire, Theiler said.

Any pregnant woman who experiences flu symptoms should call her doctor right away, Theiler said.

"They shouldn't wait it out at home or tough it out like they might do if they weren't pregnant," Theiler said. Again, anti-viral drugs would be the treatment of choice.

The bottom line, Theiler said, is that the flu is a "very bad thing for maternal mortality that's easy for us to prevent." In 2009, she said, the H1N1 epidemic increased the rate of deaths among pregnant women. That rate is typically very stable, Theiler said.

The rate of deaths "noticeably" increased just because of the flu, she said, "so that's a scary thing for us."

All Human-Made Objects on Earth Amount to 30 Trillion Tons

It's safe to say that humans have accumulated a lot of stuff over the years. Scientists recently discovered that all objects on Earth created by people adds up to an astoundingly large figure.

How large? According to a new study, the estimated mass of every bit of urban and rural infrastructure, every vehicle and machine, every device and construction on land, sea and in the air, every piece of technology, and all the garbage in landfills, is approximately 30 trillion tons.  

All of these objects are collectively known as Earth's "technosphere." Distributed evenly over the planet's surface, the technosphere would translate into about 110 pounds (50 kilograms) for every 11 square feet (1 square meter), the researchers said.

"It is all of the structures that humans have constructed to keep them alive, in very large numbers now, on the planet: houses, factories, farms, mines, roads, airports and shipping ports, computer systems, together with its discarded waste," study co-author Jan Zalasiewicz, a professor of palaeobiology at the University of Leicester, in the United Kingdom, said in a statement.

"The technosphere is a system, with its own dynamics and energy flows – and humans have to help keep it going to survive," Zalasiewicz said.

The appearance of the technosphere is linked to a newly-described geological age called the Anthropocene — a period defined by humanity's reshaping of Earth — which extends from the 1950s to the present.

Unlike Earth's biosphere — the parts of the planet that sustain life — the technosphere does a poor job of recycling the materials that make it up. Instead of breaking down and refueling growth, elements of the technosphere simply take up more space in landfills.

"The technosphere may be geologically young, but it is evolving with furious speed, and it has already left a deep imprint on our planet," Zalasiewicz added.

Black Death 'Plague Pit' with 48 Skeletons Is 'Extremely Rare' Find

A 14th-century mass burial pit full of victims of the Black Death has been discovered at the site of a medieval monastery hospital, according to archaeologists.

Researchers uncovered 48 skeletons — 27 of which were children — at an "extremely rare" Black Death burial site in Lincolnshire, in the United Kingdom, they said. DNA testing of teeth that were uncovered at the site revealed the existence of plague bacteria, the scientists said.

The presence of such a large burial site suggests that the community was overwhelmed by the number of victims of the Black Death, said lead archaeologist Hugh Willmott, a senior lecturer in European historical archaeology at the University of Sheffield. A mass grave would have been the easiest way to cope with the number of people who died during the outbreak.

"Despite the fact it is now estimated that up to half the population of England perished during the Black Death, multiple graves associated with the event are extremely rare in this country," Willmott said in a statement.

The bubonic plague (commonly called the Black Death) was one of the worst pandemics in human history, killing an estimated 75 million to 200 million people in Europe and Asia during the 1300s, according to the U.S. Centers for Disease Control and Prevention.

Previously identified 14th-century sites with skeletons that showed evidence of the presence of plague were historically documented cemeteries in London. In these instances, Willmott said that local authorities would have been forced to create emergency burial grounds for the large numbers of urban dead.

The Lincolnshire site, located in a rural and previously unknown area, sheds light on how difficult it was for small communities to cope with such a devastating threat, Willmott said.

"While skeletons are interesting, they just represent the end of somebody's life, and actually what we are interested in as archaeologists is the life they led before they died," Willmott said. "One of the ways we can connect with that is through the everyday objects they left behind."

A Tau Cross pendant was among the artifacts that the dig uncovered. It was likely used as a cure against a condition that was called St. Anthony’s fire, which was likely one of any number of skin conditions, according to such medical organizations as the American Phytopathological Society. The cross was found in an excavated hospital building that belongs to the Thornton Abbey monastery, the researchers said.

Prior to the recent discovery, the Abbey site was "just an ordinary green field grazed by sheep for hundreds of years," Willmott said. "Like many fields across England, as soon as you take away the turf, layers of history can be revealed by archaeology."

Why Do Our Feet Smell Worse in the Winter

Summer is all sweat and exposed toes, so you'd think foot odor would be at its peak in that season. Not so. As the weather turns cooler, feet often turn smellier; at least, that's what anecdotal evidence suggests.

Blame shoes and socks. Enclosing the foot increases heat and traps sweat, said Robert Kornfeld, a doctor of podiatric medicine who runs a holistic and restorative foot and ankle practice in New York.

"If the foot is allowed to [air out] efficiently, you don't build up the breeding ground for bacteria," Kornfeld told Live Science

Stinky feet

Feet on their own don't stink. The real culprits are the bacteria that live on the skin, feeding off the compounds in sweat. A 2006 study in the Canadian Journal of Microbiology found that Staphylococcus epidermidis, a common resident of the skin, creates a compound called isovaleric acid when feeding off an amino acid in sweat called leucine. Isovaleric acid happens to smell rather like pungent cheese.

Another bacteria species, Bacillus subtilis, was also associated with strong odor, the researchers found. These rod-shaped bacteria thrive in the human gastrointestinal tract as well as on the skin.

Depending on the materials you wear, you may be providing these bacteria and others a chance to flourish. Cotton tends to absorb and wick away moisture; synthetic fabrics don't absorb moisture, but instead trap it between fibers. A 2007 study published in the Textile Research Journal found that polyester fabrics are stinkier than cotton or wool. In another study, this one published in 2014, researchers came to the same conclusion after asking subjects to get sweaty by bicycling in either synthetic or natural shirts. Polyester clothing was rated significantly smellier, less pleasant, mustier and more sour than cotton clothing.

Thus, podiatrists tend to give fashion advice to patients who come in complaining of foot stink.

"I tell them to make sure they wear a cotton sock as opposed to a nylon sock," said Rondrick Williamson, a podiatrist in Atlanta. "Cotton is going to breathe a little more."

Defeating the stink

Other steps in preventing foot odor also involve banishing moisture and preventing bacteria from gaining a toehold (sorry). Williamson said he tells his patients to sprinkle shoes with a little anti-fungal powder at the end of each day; this keeps down moisture and prevents nasty infections like athlete's foot, caused by a fungus, from gaining ground. For bad cases, a spritz of Lysol in the shoes can help, too, he said. He also recommended that people with particularly sweaty feet change their socks once or twice during the day, giving bacteria less time to grow.

Kornfeld said he advocates dietary changes, including getting rid of refined sugars, to strengthen the immune system and keep pathogenic bacteria at bay. He also suggested a roll-on antiperspirant applied to the foot. People who are chronically stressed also tend to sweat more, he said, so foot odor is sometimes a sign of a wider systemic issue.

"What's interesting about foot odor is a lot of people are so embarrassed they won't even go to a doctor," Kornfeld said. "But there's help out there."  

What Tangled Web: Galaxy's Messy 'Threads' Star in New Pic

A striking new image from the Hubble Space Telescope captures an extremely detailed view of the galaxy NGC 4696 and the tangled, thread-like filaments stretching from its bright galactic core.  

Located roughly 150 million light-years from Earth, NGC 4696 is a member of the Centaurus galaxy cluster — a group of hundreds of galaxies bound together by gravity in the constellation of Centaurus. NGC 4696 is an elliptical galaxy, which means it boasts a round, elongated shape and lacks the distinctive swirling arms of spiral galaxies. 

What's more, NGC 4696 is the brightest member of the Centaurus galaxy cluster, and belongs to a group of "some of the biggest and brightest galaxies known in the universe," according to a statement from the European Space Agency. 

The recent Hubble telescope observations provided the most detailed view of the galaxy's intricate structure captured to date. Using these observations, an international team of scientists led by astronomers from the University of Cambridge took a closer look at the swirling filament structures. 

"They found that each of the dusty filaments has a width of about 200 light-years and a density some 10 times greater than the surrounding gas," ESA officials said in the statement. "These filaments knit together and spiral inwards towards the center of NGC 4696, connecting the galaxy's constituent gas to its core."

The unique structure of NGC 4696 likely resulted from an active supermassive black hole that lies at the galaxy's core. Energy generated by the black hole heats gas within the galaxy's inner regions and propels that material outward, creating the marbling effect seen in the Hubble telescope photo. 

"It appears that these hot streams of gas bubble outwards, dragging the filamentary material with them as they go. The galaxy's magnetic field is also swept out with this bubbling motion, constraining and sculpting the material within the filaments," ESA officials said in the statement. "At the very center of the galaxy, the filaments loop and curl inwards in an intriguing spiral shape, swirling around the supermassive black hole at such a distance that they are dragged into and eventually consumed by the black hole itself." 

Surprisingly, NGC 4696 consists of mostly old or aging stars, even though it has a large reservoir of gas and dust that would otherwise give birth to new stars, ESA officials said. Learning more about the complex structure of NGC 4696 may help scientists better understand why so many other nearby galaxies in the universe appear to be in a similar dormant state.