Autism linked to induced or augmented labor, study says

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August 13th, 2013

As scientists struggle to understand the causes of autism, a potential new pattern has emerged: The condition is associated with induced or augmented labor, according to a new study.

Induction means stimulating contractions before spontaneous labor begins. Augmentation means helping contractions become stronger, longer or more frequent. Both of these methods of expediting deliveries have helped mothers who have health conditions that could be detrimental to them or their child.

The researchers did not prove that these treatments cause autism. Women should not read the new study, which is published in the journal JAMA Pediatrics, and decide against expediting labor on that basis, said Simon Gregory, researcher at Duke University Medical Center and lead author of the study.

“It’s a decision between them and their healthcare provider,” Gregory said, but the data do not “outweigh the risks that would come with just not wanting to be induced or augmented at all, because then you’re the placing the mother and the infant’s life at risk.”

Background

Autism spectrum disorders are developmental conditions characterized by social, communication and behavioral difficulties.

About 1 in 88 children has a diagnosed autism spectrum disorder, according to the latest estimate from the Centers for Disease Control and Prevention.

Although there is evidence that genetics plays a role, environmental factors may also be at play in altering normal development. A recent study of twins found that susceptibility to autism can increase in prenatal and early postnatal environments.

Methods

The study looked at more than 625,000 records of children’s birth and education from North Carolina. Researchers obtained information on the demographics of both parents, the mother’s medical history age at pregnancy, and infant health.

Although this is a large sample size, study authors could not control for every variable that might have influenced the results. They did not have information about paternal age, for example, or what medications the mothers were taking. Researchers also did not obtain data about where on the autism spectrum the children fall in this study.

Results

Researchers found a strong link between treatments to expedite labor and males who had autism; for females, less so.

Male infants born in deliveries in which labor was both induced and augmented were 35% more likely to have autism than those whose mother did not have either of these treatments. For induction alone, risk was elevated 18%. For augmentation alone, risk went up 15%.

The risk to females was not significantly elevated when labor was both induced and augmented, or induced alone. The likelihood of autism went up with augmentation alone, 21%.

“The risk is modest but significant, particularly considering that this is a potential risk factor many pregnant women may be exposed to during labor,” according to a statement from Autism Speaks, a leading autism science and advocacy organization.

The gender gap seen in the study is intriguing to scientists, Gregory said, because autism is more common in males in general – in fact, nearly five times as many boys than girls have autism spectrum disorders.

What it means, however, is unclear.

Researchers also found support for other autism risk factors that previous studies have established. Older maternal age raised the risk 30%, being first born increased risk 21%, and having a mother with gestational diabetes upped the risk by 24%.

They did not find any increased risk for children born in Cesarean sections compared to vaginal births.

Implications

This data does not demonstrate that induced or augmented labor causes autism. It only shows an association; scientists do not yet know what explains the connection.

Gregory said there could be a number of underlying factors that this study did not directly address, including the health of the mother, drugs used to induce or augment birth, fetal stress, or other medications that the mother is taking. The act of inducing or augmenting may be to blame, but alternatively the medical and obstetric conditions around those treatments could have something to do with it, or even some other events that commonly occur to women whose labor is expedited. At this stage, no one knows.

But researchers say the underlying mechanism is worth looking into, given that expedited labor isn’t rare. About 23% of births in the United States in 2008 were induced, and 17% were augmented in 2002, Gregory said.

“This is the largest study to date demonstrating an association between induced or augmented childbirth and autism, and the next step is for research to better understand the possible mechanisms behind this relationship,” according to a statement from Autism Speaks.

Gregory and colleagues want to go back to these medical records and dig deeper, but also study other mothers and children going forward to see if they can figure out why they’re at increased risk.

CNN’s John Bonifield contributed to this report

Urban Moms at Greater Risk for Postpartum Depression

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August 12th, 2013

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Researchers are narrowing in on the host of factors that can contribute to postpartum depression, from genes to social connections. The latest work focuses on where a new mother lives.

The new study, published in the journal Canadian Medical Association Journal (CMAJ), looked at whether urban or rural locales played a role in postpartum depression rates.

More than 6,400 women who lived in a variety of different geographical areas, including urban, rural, semi-urban and semi-rural areas, participated in the 2006 Canadian Maternity Experiences Survey. (Rural living was defined as settlements with fewer than 1,000 people but more than 400 people per square kilometer. Semirural settings included up to 30,000 people, while semi-urban was defined as including 30,000 to 499,999 residents and urban areas included 500,000 people or more.) They also accounted for whether a woman commuted for work to urban places.

Overall, 7.5% of the women who had recently given birth in the weeks prior to the survey developed postpartum depression, but women from urban areas were at a greater risk, with a 10% rate, compared to 6% of women in rural areas, nearly 7% in semi-rural areas and 5% in semi-urban areas who developed the condition. The discrepancy is likely due to the disproportionate distribution of known risk factors such as social support and a prior history of depression that have been previously associated with postpartum depression. In the current study, for example, many of the city-dwelling mothers who developed postpartum were members of immigrant populations, which typically have weaker social support networks.

That could explain the counterintuitive result that a woman living among thousands of people in an urban setting, where post natal care and support may be more accessible than in less populated rural areas, can still experience social isolation that can contribute to feelings of helplessness and despondence. Paula Caplan, a clinical and research psychologist at Harvard University and author of “Don’t Blame Mother: Mending the Mother-Daughter Relationship,” who was not affiliated with the study, says that women living in urban environments are also likely to be working multiple jobs, and to be living in poverty. These stressors, on top of raising children, can test the limits of a new mother’s coping skills.

“People say poor mothers suffer from depression. Why is this a surprise? If you’re trying to be a good mother, it is very hard if you are poor and if you are isolated without having a sense of helplessness,” says Caplan.

Changes in the family dynamic also play a role; women are more likely to live further away from home than they have in the past, which means they are forced to manage without help from family members. While social networks may be more extensive thanks to social media, those connections still can’t replace the support and reassurance provided by the physical presence of a friend or loved one — especially for a new mother. “There are mommy blogs and social media, but there is no substitute for having someone right there who can break down our isolation and tell you you’re doing fine and your kids are okay,” says Caplan.

While hormones as well as possible genetic markers have also been connected to postpartum depression, Caplan believes that classifying the condition as a mental or physiological problem could take the focus away from social changes that could be made to support mothers. As the study results suggest, isolation and lack of social support can intensify feelings of discouragement, being overwhelmed, and loneliness that any new mother naturally experiences.

“We have completely unreasonable expectations for mothers,” says Caplan. “We live in a mother-blaming society where mothers get blamed for almost anything that goes wrong with their child. Mothers can feel isolated or scared to death. There are social changes that need to be made. These women do not need to be treated for alleged mental illness.” The study authors say better daycare options and more supportive services for women who have recently given birth could alleviate some of the burden that mothers feel. And as the results show, these services are needed not just in sparsely populated areas but in densely packed urban ones as well, since it’s possible to feel lonely even when you’re surrounded by people.

Chocolate craving comes from total sensory pleasure

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August 7th, 2013

By Philippa Roxby Health reporter, BBC News

A chocolate lover’s dream? Overflowing molten chocolate

For most of us, chocolate is a guilty pleasure. We crave it because it tastes wonderful and sweet – although we know we should really be stretching for the fruit bowl.

The British are particularly fond of chocolate. Research shows that, on average, Britons enjoy about 11kg (24lb) of chocolate a year, making the UK one of the biggest consumers of chocolate in the world. Only the Swiss and Germans eat more.

But a recent study suggests that chocolate cravings are not a modern phenomenon. In fact, chocoholism may date back to the 18th Century and beyond.

Cacao beans, which are the basic component of chocolate, were roasted, ground and drunk with water by the Mayans from around 2,000 years ago.

In the 14th Century, the Aztecs concocted chocolate drinks with flavourings and used the beans to treat a number of common ailments.

Then in the late 1700s in Mexico, a young doctor started seeing chocolate as harmful, rather than medicinal. He blamed an increase in hysteria among women and nuns in several cities on their excessive consumption of chocolate.

Was this actually an extreme form of chocolate craving?

According to a paper presented at the International Congress on the History of Science, Technology and Medicine at the University of Manchester this weekend, cacao was very popular at the time and could be served hot or cold for medicinal or pleasure purposes.

Nuns were particularly privileged, says author Dr Mauricio Sanchez Menchero, and they “were able to have as much chocolate as they wished for regardless of costs”.

Even a sharp rise in the price of chocolate did not affect consumption levels in convents, he says.

So when new laws were brought in which forced nuns to do away with personal servants and make their own food and drinks, their intake of cacao was “greatly diminished” and they were afflicted by hysterical attacks.

Dr Jose Bartolache was convinced that the cacao plant played a major role in ill health, although very tight clothes and going to bed late were other supposed causes.

The bitter, dark chocolate eaten by the nuns is nothing like the sugary, flavoured milk chocolate which is popular today – but the reaction is understandable.

Many people would claim to crave chocolate and enjoy the feeling that eating it induces.

The key to this may be a chemical called anandamide, which is similar to the compounds released when cannabis is taken.

It is released in small quantities when we eat chocolate and it creates a relaxing feeling.

Prof Philip K. Wilson, joint author of Chocolate as Medicine – A Quest over the Centuries with Jeffrey Hurst, says what lies behind the aphrodisiac qualities of chocolate is still to be answered.

“It’s difficult to tease apart which chemicals may be contributing to which psychological functions. There are over 500 chemicals in consumer chocolate products, so there’s a lifetime of chemical analysis still to be done,” says Prof Wilson.

His hunch is that the “almost seductive” texture of chocolate is as important as its ingredients.

Dr Barry Smith, director of the Centre for the Study of the Senses at Birkbeck University of London, agrees.

He says the combination of the smoothness and creaminess of chocolate in the mouth, the sweetness of the taste – boosted by vanilla flavouring – and the smell of it before it even hits the taste buds make chocolate-eating a hugely pleasurable experience.

And this contrasts with other foods.

“Cheese might smell stinky but it can taste great. Brewed coffee always smells fantastic but it’s not the same taste when you drink it – and that’s disappointing.

“But with chocolate, the pleasure of anticipation and the reward in eating it match up. The aroma and the taste are the same.

“And that matters because there are two sorts of pleasure involved,” says Dr Smith.

He recommends taking time to savour a piece of chocolate, then comparing that experience with eating it quickly.

“When you start eating it, turn it around in your mouth to get the melting quality which strokes the tongue.

“Receptors in the tongue then respond to this stroking and it’s a different feeling from touch.

“That’s why we love a velvety wine or double cream – it’s the feeling on our tongues.”

Both men and women can experience the pleasure of chocolate but women’s superior sense of smell means that they may be more likely to enjoy the ride.

And yet not all countries and cultures show cravings for chocolate.

There is a theory that because chocolate is perceived as “bad food” – because of its sugar and fat content – we try to avoid eating it, and this leads us to crave it, because it is forbidden.

However in recent years, chocolate’s press has improved to the extent that it is now known to have some health benefits.

The type of polyphenols present in cacao beans, known as flavanoids, are antioxidants and there is some evidence that this action may help protect our hearts – but only as part of a healthy and balanced diet.

As for whether chocolate can actually improve our mood, there is limited evidence according to neuroscientists.

But millions of women (and nuns) can’t be wrong, can they?

Pregnancy length ‘varies naturally by up to five weeks’

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August 7th, 2013

The length of pregnancy can vary naturally by as much as five weeks, research suggests.

The study of 125 women is the first to calculate gestation by pinpointing the exact time of conception.

It found age, time to implantation and their own weight as babies were also linked to pregnancy length.

An expert said the findings, in the journal Human Reproduction, challenged whether a “due date” for women was helpful.

Due dates can be calculated from working out 280 days after the start of the woman’s last menstrual period, or more accurately by ultrasound.

Yet only 4% of women deliver when predicted and only 70% within 10 days of their estimated due date.

Researchers ‘surprised’

The research team at the US National Institute of Environmental Health Sciences measured hormone concentrations in daily urine samples taken from women trying to conceive naturally to determine exactly when ovulation and implantation of the fertilised egg had occurred.

They found that the average length from ovulation to birth was 268 days, just over 38 weeks.

Once they had excluded six premature births, they found that gestation varied naturally by as much as 37 days.

Dr Anne Marie Jukic said: “We were a bit surprised by this finding. We know that length of gestation varies among women, but some part of that variation has always been attributed to errors in the assignment of gestational age.

“Our measure of length of gestation does not include these sources of error, and yet there is still five weeks of variability. It’s fascinating.”

The study also showed that embryos that took longer to implant also took longer from implantation to delivery.

Older women were more likely to have longer pregnancies and there was also a link between gestation and a mother’s weight when she was born.

The researchers also found that length of previous or subsequent pregnancies was related to the length of the one being studied, suggesting a consistency about when women deliver.

But they said it was too early to make any clinical recommendations.

“I think the best that can be said is that natural variability may be greater than we have previously thought and, if that is true, clinicians may want to keep that in mind when trying to decide whether to intervene on a pregnancy,” said Dr Jukic.

Dr Virginia Beckett, spokesperson for the Royal College of Obstetricians and Gynaecologists, said very little was known about the exact mechanisms that determine when labour begins.

“This is a very interesting piece of work and knowing when is the right time to deliver is a huge issue.”

She added it supports the suggestion that giving someone a “due date” may not be a great idea and can make women feel anxious when they go over.

“It would be better to say, ‘You will be delivered by this time’ to take the pressure off.”

Hotter World Means Hotter Tempers, More Violence

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August 5th, 2013

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Climate change may be one of the factors contributing to violence within and among societies, according to the latest study.

Whether it’s a drought in India, a heat wave in the U.S. or an extreme change in rainfall in Africa, Asia or South America, the outcomes tend to be the same: more wars, more murder, more riots and more domestic violence.

The intimate connection between climate and human interaction has long been documented, and could have contributed to the downfall of Chinese and Mayan empires, say the study’s authors. Reporting in the journal Science,  lead author Solomon Hsiang, assistant professor of public policy at the University of California in Berkeley. and his colleagues analyzed 60 studies of climate change and human conflict at several levels, from domestic violence to the collapse of entire civilizations. “All around the world across different societies in the modern world as well as throughout history, we find that human conflict seems to be linked to changes in climate,” says Hsiang.

Rising temperatures have the greatest effect on human conflict; the equivalent of a five degree Fahrenheit increase in an average U.S. county over a month, for example, could raise the odds of personal violence such as assault, murder and domestic violence by 4%, and the risk of civil war, riots or ethnic violence by 14%.

Rainfall and drought can also contribute to conflict; the researchers found spikes in domestic violence in India, as well as higher murder rates in the U.S. and in Tanzania and civil wars in tropical regions tied to relatively small changes in rain or temperature.

The findings reinforce previous studies that linked climate change to human affairs, and raise concerns about the potential impact that changing environmental conditions will have on the stability of societies in coming decades. Most climate change estimates predict a rise of two to four standard deviations in temperature, rainfall or drought by 2050, which suggests a 30% greater risk of intergroup conflicts, says Hsiang.

“It’s a very, very impressive review of the literature,” says Dr. Mark Shapiro, chief of acute care surgery at Duke University Medical Center, who has published research on the link between heat and assaults, but was not associated with the latest study.

Heat could provide fertile ground for interpersonal violence by bringing people into closer contact indoors to seek relief. Assault, rape— even the number of baseball pitchers who retaliate against batters by hitting them with pitches — all rise with temperature, studies show. Even noise can become a more anger-inducing irritant, according to Dutch researchers.

On a population level, climate change may have more indirect effects on social stability; as crops fail due to drought or flood, for instance, migration may provoke conflicts as communities compete for more limited resources.

However, Shapiro says it’s not clear that rising global temperatures will necessary lead to ever-escalating conflict. His own work found a direct, linear relationship between assault and temperature, but other studies suggested there may be a threshold at which violence starts to decline.

Still, says Hsiang, his data show that man is historically ill-equipped to cope with changing climate, and may continue to fall prey to the influence that higher temperatures and more rainfall can have on the stability of both personal and society relationships. “We need to understand why climate changes cause conflict so we can help societies to adapt to these events and avoid the violence,” he said in a statement.