Posts tagged pregnancy

A researcher at the University of Wisconsin-Milwaukee (UWM) has added to a growing body of evidence that links autism to air pollutants such as those generated by cars and trucks.

Amy Kalkbrenner’s study, published this week online at the journal Epidemiology, showed that pollution’s impact on autism rates in North Carolina is similar to results of pollution-autism studies in California – despite weather and climate differences between the two states.

In addition, the work of Kalkbrenner and her colleagues, building on previous studies, showed that women in the third trimester of pregnancy were more susceptible to the damaging effects of air pollution on their unborn child.

“It adds another piece supporting the hypothesis that environmental chemicals are part of the autism puzzle,” says Kalkbrenner, an assistant professor in UWM’s Joseph J. Zilber School of Public Health. Autism, a spectrum of disorders affecting interpersonal relations and work achievement, now affects some 1 in 68 children in the U.S.

Her research team focused on exposure to coarse and fine particulate matter, known as PM₁₀, which arises in part from traffic-related air pollution. The study evaluated records in the two states, covering pre-conception through the first birthday for 87,000 children in North Carolina and 77,500 in California born in the mid-to-late 1990s. Key regions in each state were selected based on researchers’ ability to simultaneously measure the level of particulate matter present, and know which children had autism in these regions.

Researchers used a new, more exact tool to measure the levels of particulate matter in smaller slices of time, based on pollution at the family’s address during pregnancy. With this method, they were able to compare exposures during specific weeks of pregnancy. The approximately one thousand children who later developed some form of autism spectrum disorders were then compared to all other children.

Kalkbrenner says it was important to look at eastern states because of the differences in climate, seasonal weather patterns and the chemical make-up of the particulate matter that might impact brain development. “Evidence for a link between a chemical exposure and a health impact like autism is stronger when it can be shown in more than one region.” The team found that the concentration of particulate matter was highest among children born in summer months in North Carolina and those born in fall and winter months in California.

Reasons for increased susceptibility in the third trimester of pregnancy are not known at this time. However, Kalkbrenner says this finding is consistent with theories that show links between autism and altered brain network development, specifically synaptic connections that are developing during the final months of pregnancy.

“We’ve now had three solid studies saying the same thing. The evidence is pretty compelling that something is going on with air pollution and autism,” says Kalkbrenner, who adds that further study is needed to determine the neurodevelopmental impacts of specific chemical pollutants during precise developmental windows.

(Source: www5.uwm.edu)

In some women abnormally high levels of a common and pervasive chemical may lead to adverse effects in their offspring. The study, published recently in the Journal of Clinical Endocrinology & Metabolism, is the first of its kind to shed light on the possible harmful side effects of perchlorate in mothers and their children.

Using data from the Controlled Antenatal Thyroid Study (CATS) cohort, researchers at Boston University School of Medicine (BUSM) and Cardiff University studied the effect of perchlorate, an environmental contaminant found in many foods and in some drinking water supplies, and its effects on children born to mothers with above average levels of this substance in their system. They studied 487 mother-child pairs from women with underactive thyroid glands and in the 50 women with the highest levels of perchlorate in their body, their offspring had below average IQ levels when compared to other children.

"The reason people really care about perchlorate is because it is ubiquitous. It’s everywhere," said Elizabeth Pearce, MD, MSc, associate professor of medicine at BUSM. "Prior studies have already shown perchlorate, at low levels, can be found in each and every one of us."

Perchlorate is a compound known to affect the thyroid gland, an organ needed to help regulate hormone levels in humans. According to Pearce previous studies have attempted to implicate this anti-thyroid activity in pregnant mothers as a possible cause of hypothyroidism, or an underactive thyroid gland. Hypothyroidism in newborns and children can lead to an array of unwelcome side effects, including below average intelligence.

(Source: eurekalert.org)

Mozart, Beethoven or even Shakespeare — pregnant mothers have been known to expose their babies to many forms of auditory stimulation. But according to researchers at the University of Florida, all a baby really needs is the music of mom’s voice.

Research published in the most recent issue of the journal Infant Behavior and Development shows that babies in utero begin to respond to the rhythm of a nursery rhyme — showing evidence of learning — by 34 weeks of pregnancy and are capable of remembering a set rhyme until just prior to birth. Nursing researcher Charlene Krueger and her team studied pregnant women who recited a rhyme to their babies three times a day for six weeks, beginning at 28 weeks’ gestational age, which is the start of the third trimester of pregnancy.

“The mother’s voice is the predominant source of sensory stimulation in the developing fetus,” said Krueger, an associate professor in the UF College of Nursing. “This research highlights just how sophisticated the third trimester fetus really is and suggests that a mother’s voice is involved in the development of early learning and memory capabilities. This could potentially affect how we approach the care and stimulation of the preterm infant.”

Krueger’s team recruited 32 pregnant women during their 28th week of pregnancy, as determined by fetal ultrasound. The participants were between 18 and 39 years of age, spoke English as a primary language and were pregnant with their first baby. Once recruited, the women were randomly assigned to either an experimental or a control group. The mean age of the women in the group was 25. In addition, 68 percent of the women were white, 28 percent were black and 4 percent were of another race or ethnicity.

From 28 to 34 weeks of pregnancy, all mothers in the study recited a passage or nursery rhyme out loud twice a day and then came in for testing at 28, 32, 33 and 34 weeks’ gestation. To determine whether the fetus could remember the pattern of speech at 34 weeks of age, all mothers were asked to stop speaking the passage. Then the fetuses were tested again at 36 and 38 weeks’ gestational age.

During testing, researchers used a fetal heart monitor, similar to what is used during traditional labor and delivery, to record heart rate and determine any changes. Researchers interpret a small heart rate deceleration in the fetus as an indicator of learning or familiarity with a stimulus.

At testing, the fetuses in the experimental group were played a recording of the same rhyme their mother had been reciting at home but spoken by a female stranger. Those in the control group heard a different rhyme also spoken by a stranger. This was to help determine if the fetus was responding simply to its mother’s voice or to a familiar pattern of speech, which is a more difficult task, Krueger said.

The researchers found that the fetus’ heart rate began to respond to the familiar rhyme recited by a stranger’s voice by 34 weeks of gestational age — once the mother had spoken the rhyme out loud at home for six weeks. They continued to respond with a small cardiac deceleration for as long as four weeks after the mother had stopped saying the rhyme until about 38 weeks. At 38 weeks, there was a statistically significant difference between the two groups in responding to the strangers’ recited rhymes — the experimental group who heard the original rhyme responded with a deeper and more sustained cardiac deceleration, whereas the control group who heard a new rhyme responded with a cardiac acceleration.

Further research is needed to more fully understand how ongoing development affects learning and memory, Krueger said. Her aim is to recognize how this type of research can influence care in preterm infants and their long-term outcomes.

“This study helped us understand more about how early a fetus could learn a passage of speech and whether the passage could be remembered weeks later even without daily exposure to it,” Krueger said. “This could have implications to those preterm infants who are born before 37 weeks of age and the impact an intervention such as their mother’s voice may have on influencing better outcomes in this high-risk population.”

(Source: news.ufl.edu)

Pregnant women who lived in close proximity to fields and farms where chemical pesticides were applied experienced a two-thirds increased risk of having a child with autism spectrum disorder or other developmental delay, a study by researchers with the UC Davis MIND Institute has found. The associations were stronger when the exposures occurred during the second and third trimesters of the women’s pregnancies.

The large, multisite California-based study examined associations between specific classes of pesticides, including organophosphates, pyrethroids and carbamates, applied during the study participants’ pregnancies and later diagnoses of autism and developmental delay in their offspring. It is published online today in Environmental Health Perspectives.

“This study validates the results of earlier research that has reported associations between having a child with autism and prenatal exposure to agricultural chemicals in California,” said lead study author Janie F. Shelton, a UC Davis graduate student who now consults with the United Nations. “While we still must investigate whether certain sub-groups are more vulnerable to exposures to these compounds than others, the message is very clear: Women who are pregnant should take special care to avoid contact with agricultural chemicals whenever possible.”

California is the top agricultural producing state in the nation, grossing $38 billion in revenue from farm crops in 2010. Statewide, approximately 200 million pounds of active pesticides are applied each year, most of it in the Central Valley, north to the Sacramento Valley and south to the Imperial Valley on the California-Mexico border. While pesticides are critical for the modern agriculture industry, certain commonly used pesticides are neurotoxic and may pose threats to brain development during gestation, potentially resulting in developmental delay or autism.

The study was conducted by examining commercial pesticide application using the California Pesticide Use Report and linking the data to the residential addresses of approximately 1,000 participants in the Northern California-based Childhood Risk of Autism from Genetics and the Environment (CHARGE) Study. The study includes families with children between 2 and 5 diagnosed with autism or developmental delay or with typical development. It is led by principal investigator Irva Hertz-Picciotto, a MIND Institute researcher and professor and vice chair of the Department of Public Health Sciences at UC Davis. The majority of study participants live in the Sacramento Valley, Central Valley and the greater San Francisco Bay Area.

Twenty-one chemical compounds were identified in the organophosphate class, including chlorpyrifos, acephate and diazinon. The second most commonly applied class of pesticides was pyrethroids, one quarter of which was esfenvalerate, followed by lambda-cyhalothrin permethrin, cypermethrin and tau-fluvalinate. Eighty percent of the carbamates were methomyl and carbaryl.

For the study, researchers used questionnaires to obtain study participants’ residential addresses during the pre-conception and pregnancy periods. The addresses then were overlaid on maps with the locations of agricultural chemical application sites based on the pesticide-use reports to determine residential proximity. The study also examined which participants were exposed to which agricultural chemicals.

“We mapped where our study participants’ lived during pregnancy and around the time of birth. In California, pesticide applicators must report what they’re applying, where they’re applying it, dates when the applications were made and how much was applied,” Hertz-Picciotto said. “What we saw were several classes of pesticides more commonly applied near residences of mothers whose children developed autism or had delayed cognitive or other skills.”

The researchers found that during the study period approximately one-third of CHARGE Study participants lived in close proximity – within 1.25 to 1.75 kilometers – of commercial pesticide application sites. Some associations were greater among mothers living closer to application sites and lower as residential proximity to the application sites decreased, the researchers found.

Organophosphates applied over the course of pregnancy were associated with an elevated risk of autism spectrum disorder, particularly for chlorpyrifos applications in the second trimester. Pyrethroids were moderately associated with autism spectrum disorder immediately prior to conception and in the third trimester. Carbamates applied during pregnancy were associated with developmental delay.

Exposures to insecticides for those living near agricultural areas may be problematic, especially during gestation, because the developing fetal brain may be more vulnerable than it is in adults. Because these pesticides are neurotoxic, in utero exposures during early development may distort the complex processes of structural development and neuronal signaling, producing alterations to the excitation and inhibition mechanisms that govern mood, learning, social interactions and behavior.

“In that early developmental gestational period, the brain is developing synapses, the spaces between neurons, where electrical impulses are turned into neurotransmitting chemicals that leap from one neuron to another to pass messages along. The formation of these junctions is really important and may well be where these pesticides are operating and affecting neurotransmission,” Hertz-Picciotto said.

Research from the CHARGE Study has emphasized the importance of maternal nutrition during pregnancy, particularly the use of prenatal vitamins to reduce the risk of having a child with autism. While it’s impossible to entirely eliminate risks due to environmental exposures, Hertz-Picciotto said that finding ways to reduce exposures to chemical pesticides, particularly for the very young, is important.

“We need to open up a dialogue about how this can be done, at both a societal and individual level,” she said. “If it were my family, I wouldn’t want to live close to where heavy pesticides are being applied.”

(Source: ucdmc.ucdavis.edu)

When a woman experiences a stressful event early in pregnancy, the risk of her child developing autism spectrum disorders or schizophrenia increases. Yet how maternal stress is transmitted to the brain of the developing fetus, leading to these problems in neurodevelopment, is poorly understood. 

New findings by University of Pennsylvania School of Veterinary Medicine scientists suggest that an enzyme found in the placenta is likely playing an important role. This enzyme, O-linked-N-acetylglucosamine transferase, or OGT, translates maternal stress into a reprogramming signal for the brain before birth.

(Image caption: Mice with reduced OGT in their placenta were shorter and leaner than their normal counterparts.)

“By manipulating this one gene, we were able to recapitulate many aspects of early prenatal stress,” said Tracy L. Bale, senior author on the paper and a professor in the Department of Animal Biology at Penn Vet. “OGT seems to be serving a role as the ‘canary in the coal mine,’ offering a readout of mom’s stress to change the baby’s developing brain.”

Bale also holds an appointment in the Department of Psychiatry in Penn’s Perelman School of Medicine. Her co-author is postdoctoral researcher Christopher L. Howerton. The paper was published online in PNAS this week.

OGT is known to play a role in gene expression through chromatin remodeling, a process that makes some genes more or less available to be converted into proteins. In a study published last year in PNAS, Bale’s lab found that placentas from male mice pups had lower levels of OGT than those from female pups, and placentas from mothers that had been exposed to stress early in gestation had lower overall levels of OGT than placentas from the mothers’ unstressed counterparts.

“People think that the placenta only serves to promote blood flow between a mom and her baby, but that’s really not all it’s doing,” Bale said. “It’s a very dynamic endocrine tissue and it’s sex-specific, and we’ve shown that tampering with it can dramatically affect a baby’s developing brain.”

To elucidate how reduced levels of OGT might be transmitting signals through the placenta to a fetus, Bale and Howerton bred mice that partially or fully lacked OGT in the placenta. They then compared these transgenic mice to animals that had been subjected to mild stressors during early gestation, such as predator odor, unfamiliar objects or unusual noises, during the first week of their pregnancies.

The researchers performed a genome-wide search for genes that were affected by the altered levels of OGT and were also affected by exposure to early prenatal stress using a specific activational histone mark and found a broad swath of common gene expression patterns.

They chose to focus on one particular differentially regulated gene called Hsd17b3, which encodes an enzyme that converts androstenedione, a steroid hormone, to testosterone. The researchers found this gene to be particularly interesting in part because neurodevelopmental disorders such as autism and schizophrenia have strong gender biases, where they either predominantly affect males or present earlier in males.

Placentas associated with male mice pups born to stressed mothers had reduced levels of the enzyme Hsd17b3, and, as a result, had higher levels of androstenedione and lower levels of testosterone than normal mice.

“This could mean that, with early prenatal stress, males have less masculinization,” Bale said. “This is important because autism tends to be thought of as the brain in a hypermasculinized state, and schizophrenia is thought of as a hypomasculinized state. It makes sense that there is something about this process of testosterone synthesis that is being disrupted.”

Furthermore, the mice born to mothers with disrupted OGT looked like the offspring of stressed mothers in other ways. Although they were born at a normal weight, their growth slowed at weaning. Their body weight as adults was 10-20 percent lower than control mice.

Because of the key role that that the hypothalamus plays in controlling growth and many other critical survival functions, the Penn Vet researchers then screened the mouse genome for genes with differential expression in the hypothalamus, comparing normal mice, mice with reduced OGT and mice born to stressed mothers.

They identified several gene sets related to the structure and function of mitochrondria, the powerhouses of cells that are responsible for producing energy. And indeed, when compared by an enzymatic assay that examines mitochondria biogenesis, both the mice born to stressed mothers and mice born to mothers with reduced OGT had dramatically reduced mitochondrial function in their hypothalamus compared to normal mice. These studies were done in collaboration with Narayan Avadhani’s lab at Penn Vet.

Such reduced function could explain why the growth patterns of mice appeared similar until weaning, at which point energy demands go up.

“If you have a really bad furnace you might be okay if temperatures are mild,” Bale said. “But, if it’s very cold, it can’t meet demand. It could be the same for these mice. If you’re in a litter close to your siblings and mom, you don’t need to produce a lot of heat, but once you wean you have an extra demand for producing heat. They’re just not keeping up.”

Bale points out that mitochondrial dysfunction in the brain has been reported in both schizophrenia and autism patients.

In future work, Bale hopes to identify a suite of maternal plasma stress biomarkers that could signal an increased risk of neurodevelopmental disease for the baby.

“With that kind of a signature, we’d have a way to detect at-risk pregnancies and think about ways to intervene much earlier than waiting to look at the term placenta,” she said.

Fetuses are more likely to show left-handed movements in the womb when their mothers are stressed, according to new research.

Researchers at Durham and Lancaster universities say their findings are an indicator that maternal stress could have a temporary effect on unborn babies, adding that their research highlights the importance of reducing stress during pregnancy.

However, the researchers emphasised that their study was not evidence that maternal stress led to fixed left-handedness in infants after birth. They said that some people might be genetically predisposed to being left-handed and that there are examples where right and left-handedness can switch throughout a person’s life.

Using 4d ultrasound scans, the researchers observed 57 scans of 15 healthy fetuses, recording 342 facial touches.

The fetuses were scanned at four different stages between 24 and 36 weeks of pregnancy. Researchers also asked the mothers of these babies how much stress they had experienced in the four weeks between each of the scans.

The researchers found that the more stress mothers reported, the more frequently fetuses touched their faces with their left hands. They added that a significant number of touches by the fetuses of stressed mothers were done with their left, rather than right hands - therefore fetal touches of their own faces, indicated a left-handed tendency.

As right-handedness is more common in the general population, the researchers had expected to see more of a bias towards right-handed movements in the fetuses as they grew older. The high percentage of left-handed behaviour, observed only when mothers reported being stressed, led them to conclude that maternal stress has an effect on the lateral behaviour of the babies they scanned.

The findings are published in the journal Laterality: Asymmetries of Body, Brain and Cognition.

Lead author Dr Nadja Reissland, in Durham University’s Department of Psychology, said: “Our research suggests that stressed mothers have fetuses who touch their face relatively more with their left hand.

“This suggests maternal stress could be having on effect on the child’s behaviour in the womb and highlights the importance of reducing maternal stress in pregnancy.

“Such measures may include increased emphasis on stopping stressful work early, the inclusion of relaxation classes in pre-natal care and involvement of the whole family in the pre-natal period.

“While we observed a higher degree of left-handed behaviour in the fetuses of stressed mothers than had been expected, we are not saying that maternal stress leads to a child becoming left-handed after birth, as there could be a number of reasons for this.

“The research does suggest, however, that a fetus can detect when a mother is stressed and that it responds to this stress.”

Professor Brian Francis, of Lancaster University, emphasised that the study also showed that overall preference for left or right hand varied considerably from scan to scan within each fetus, though fetuses showed more left-hand movements when mothers reported that they had experienced stress. He said: “Overall, there was no consistent handedness preference being shown by the fetuses, with most fetuses switching in preference at least once over the four scans.”

The researchers added that while mothers were asked to report their stress levels in the four weeks between scans, in practice some might have reported the stress they were experiencing at the time of being surveyed.

Previous research has shown that maternal stress in pregnancy leads to increased levels of cortisol – a hormone produced in response to stress - in mothers that could lead to an altered preference for left-sided or right-sided behaviour in fetuses.

The current study did not assess the stress levels of fetuses and Dr Reissland said that future research could examine cortisol levels in fetuses to further determine the effect of stress on lateral behaviour.

Dr Reissland added that further research was also needed to look at whether or not maternal prenatal stress had longer-term effects on the development of infants and children after birth.

(Source: dur.ac.uk)

A seven-year study of women who take antipsychotic medication while pregnant, proves it can affect babies.

The observational study, published in the journal PLOS ONE, reveals that whilst most women gave birth to healthy babies, the use of mood stabilisers or higher doses of antipsychotics during pregnancy increased the need for special care after birth with 43 per cent of babies placed in a Special Care Nursery (SCN) or a Neonatal Intensive Care Unit (NICU), almost three times the national rate in Australia.

As well as an increased likelihood of the need for intensive care, the world-first study by experts from the Monash Alfred Psychiatry Research Centre (MAPrc) and Monash University, shows antipsychotic drugs affects babies in other ways; 18 per cent were born prematurely, 37 per cent showed signs of respiratory distress and 15 per cent developed withdrawal symptoms.

Principal investigator, Professor Jayashri Kulkarni, Director of MAPrc, said the study highlights the need for clearer health guidelines when antipsychotic drugs are taken during pregnancy.

“There’s been little research on antipsychotic medication during pregnancy and if it affects babies. The lack of data has made it very difficult for clinicians to say anything conclusively on how safe it is for babies,” Professor Kulkarni said.

“This new research confirms that most babies are born healthy, but many experience neonatal problems such as respiratory distress.”

With no existing data to draw on, MAPrc established the world-first National Register of Antipsychotic Medications in Pregnancy (NRAMP) in 2005. Women who were pregnant and taking antipsychotic medication were recruited from around Australia through clinical networks in each state and territory. In all 147 women were interviewed every six weeks during pregnancy and then followed until their babies were one year old.

Antipsychotic drugs are currently used to treat a range of psychiatric disorders including schizophrenia, major depression and bipolar disorder. About 20 per cent of Australian women experience depression in their lifetime, compared to 10 per cent of men. In Australia 25 per cent of women experience postnatal depression and 20 per cent experience severe menopausal depression.

Women have much higher rates of anxiety disorders and there are equal percentages of men and women with schizophrenia (2 per cent) and bipolar disorder (about 3 per cent).

Professor Kulkarni said the emergence of new antipsychotic drugs means that many women with a well controlled psychiatric disorder are able to contemplate having babies, but there have always been concerns about the effect of treatment on their offspring.

“The potentially harmful effects of taking an antipsychotic drug in pregnancy have to be balanced against the harm of untreated psychotic illness. The good news is we now know there are no clear associations with specific congenital abnormalities and these drugs,” Professor Kulkarni said.

“However clinicians should be particularly mindful of neonatal problems such as respiratory distress, so it’s critical that Neonatal Intensive Care Units, or Special Care Nurseries are available for these babies.”

(Source: monash.edu)