October 5th, 2009 
Expectant mothers who eschew asthma treatment during pregnancy heighten the risk transmitting the condition to their offspring, according to one of the largest studies of its kind published in the European Respiratory Journal.
A research team from the Université de Montréal, the Hôpital du Sacré-Cœur de Montréal and Sainte-Justine University Hospital Research Center found that 32.6 percent of children born to mothers who neglected to treat their asthma during pregnancy developed the respiratory illness themselves.
“Uncontrolled maternal asthma during pregnancy could trigger a transient yet important reaction in the fetus that affects lung development and could subsequently increase the likelihood of a baby developing asthma in later childhood,” warns lead author Dr. Lucie Blais, a professor at the Université de Montréal’s Faculty of Pharmacy and researcher at the Hôpital du Sacré-Cœur de Montréal.
As part of the study, the research team examined a decade of health records for 8,226 children – from birth to 10 years of age – born to asthmatic mothers. Parents of these children were also mailed questionnaires requesting additional facts concerning familial medical history, lifestyle habits and environment.
“We found that failing to control maternal asthma during pregnancy clearly has an impact on asthma in offspring – a consequence that is independent of other contributing factors,” says Dr. Blais. “It is of great importance for physicians to adequately treat asthmatic mothers during pregnancy, not only for the favourable outcome of pregnancy but also for the benefit of the child.”
Related
- Smoking pregnant increases baby’s asthma risk: study
Smoking during pregancy increases the risk of a baby developing asthma up to sixfold, said a Swedish study published at the European Respiratory Society’s annual congress on Monday.
The study by Professeur Anders Bjerg of the Sunderby central hospital in Norrbotten and his specialists showed that smoking leads to babies being born underweight, a fact that has an impact on the development of asthma.
The Swedish doctors studied asthma in about 3,400 children between 1996 and 2008.
The study found that babies of smoking mothers had an average weight of 211 grammes (7.44 ounces) less than those of mothers who do not smoke.
Nearly a quarter (24.3 percent) of smoking mothers’ babies weighed less than 2.5 kilogrammes at birth against 4.1 percent for those of non-smoking women.
In underweight children of women who smoked throughout their pregnancy the asthma risk was at 23.5 percent, against 7.7 percent in children of non-smoking mothers who were born with an average weight.
- Study Links High Stress During Pregnancy To Children’s Asthma Risk
Massachusetts researchers say stress experienced by mothers during pregnancy increases the risk their children will develop asthma.
The researchers, with Brigham and Women’s Hospital and Harvard University in Boston, looked at the differences in immune function markers in umbilical cord blood between babies born to mothers in high-stress situations and those with lower stress.
They said in a statement that they found noticeable differences in patterns that could be linked to asthma later in the children’s lives.
The researchers said their study is the first to show that increased stress in urban environments could account for the high prevalence of asthma among African-American children.
Animal studies have already suggested that a mother’s stress during pregnancy can impact children’s immune system.
The study is published in the American Thoracic Society’s American Journal of Respiratory and Critical Care Medicine.
- Childhood asthma in premature babies linked to pregnancy bug
A common complication during pregnancy may predispose children born prematurely to asthma, a large study reports today.
The condition, chorioamnionitis, is inflammation of the fetal membranes and amniotic fluid from a bacterial infection. It is thought to be linked to more than half of all preterm births, before 37 weeks’ gestation, scientists write in today’s Archives of Pediatric and Adolescent Medicine.
The infection may have ascended to the uterus from the mother’s genital tract or traveled through her bloodstream from a more remote site, such as her gums or upper respiratory tract, says lead author Darios Getahun, a scientist at Kaiser Permanente Southern California’s Department of Research and Evaluation in Pasadena.
In animals, chorioamnionitis has been shown to cause lung and brain damage in offspring, Getahun says. Scientists also have found lung scarring in infants who died after pregnancies complicated by the condition.
Getahun and his co-authors analyzed electronic health records for all singleton children born at Kaiser’s Southern California hospitals in 1991 to 2007, a total of 397,852. Of those, 28,869 were preterm.
Among children born full-term, chorioamnionitis wasn’t linked to an increased risk of being diagnosed with asthma by age 8. But among those born prematurely, the condition was associated with double the risk of childhood asthma in blacks, a 70% increase in Hispanics and a 66% increase in whites. The researchers observed these differences even after accounting for other possible risk factors such as whether the mother smoked or had asthma herself. Only in Asian/Pacific Islanders preemies did chorioamnionitis not seem to make a difference in childhood asthma risk.
Getahun speculates that chorioamnionitis wasn’t related to asthma risk in full-term children because their mothers might not have had it as long as those born prematurely. But, he adds, his team didn’t have information about how early in their pregnancy women were diagnosed.
Diagnosing the condition is tricky, Getahun says, because symptoms — fever in the mother, tenderness or pain in the uterus, foul-smelling amniotic fluid — aren’t definitive, and some women never exhibit symptoms. Getahun’s team is now trying to find a marker in the mother’s blood that would signify her symptoms are because of chorioamnionitis.
A study of 1,096 children published in 2008 found a higher risk of wheezing by age 2 in preemies whose mothers had had chorioamnionitis.
- Use of Acetaminophen in Pregnancy Associated With Increased Asthma Symptoms in Children
Children who were exposed to acetaminophen prenatally were more likely to have asthma symptoms at age five in a study of 300 African-American and Dominican Republic children living in New York City. Building on prior research showing an association between both prenatal and postnatal acetaminophen and asthma, this is the first study to demonstrate a direct link between asthma and an ability to detoxify foreign substances in the body. The findings were published this week in the journal Thorax.
The study, conducted by the Columbia Center for Children’s Environmental Health at Columbia University’s Mailman School of Public Health, found that the relationship was stronger in children with a variant of a gene, glutathione S transferase, involved in detoxification of foreign substances. The variant is common among African-American and Hispanic populations. The results suggest that less efficient detoxification is a mechanism in the association between acetaminophen and asthma.
The researchers assessed the use of analgesics during pregnancy and found that 34 percent of mothers reported acetaminophen use during pregnancy, and 27 percent of children had wheeze, an asthma-related symptom. The children whose mothers had taken acetaminophen were more likely to wheeze, visit the emergency room for respiratory problems, and develop allergy symptoms, compared to those children whose mothers did not take acetaminophen. The risk increased with increasing number of days of prenatal acetaminophen use. The children in this study live in neighborhoods of New York City that have been the hardest hit by the asthma epidemic: Northern Manhattan and the South Bronx.
Acetaminophen use among children in the U.S. has increased substantially since the early 1980s and has become increasingly common among women during pregnancy so that most women in the U.S. take acetaminophen during pregnancy. This increase coincided with a doubling of the prevalence of asthma among children in the country between 1980 and 1995.
“These findings might provide an explanation for some of the increased asthma risk in minority communities and suggest caution in the use of acetaminophen in pregnancy,” says Matthew S. Perzanowski, PhD, assistant professor of Environmental Health Sciences at the Mailman School of Public Health.
Reasons for prenatal acetaminophen use vary, but in this study population the observed associations with headaches suggest pain management as likely; however, other host factors that caused mothers to take acetaminophen and also cause asthma may explain their association. While infection is one such potential confounder, the Mailman School researchers found no association between the reported use of antibiotics and acetaminophen, and adjustment for antibiotic use during pregnancy did not affect the results.
According to the researchers, the prevalence of current wheeze diminished as the children aged, from 40 percent at age one year to 25 percent, 17 percent and 27 percent at ages two, three, and five, respectively. However, the association between prenatal acetaminophen exposure and current wheeze strengthened as the children aged.
The Columbia Center for Children’s Environmental Health study adjusted relative risks for sex, race/ethnicity, birth order, maternal asthma, maternal hardship, exposure to environmental tobacco smoke, antibiotic use and postnatal acetaminophen use.
In a similar study conducted in the UK, the frequency of acetaminophen use during pregnancy and the magnitude of association in the UK study were similar to that in New York City.
- Pregnancy in Winter Months Increases Risk of Newborn Neurological Problems
Sunlight is important for our health. In these days when people are afraid of skin cancer and smother on sunscreen, Vitamin D absorption has been reduced. Vitamin D is also vital to infant development, and new research suggests that mothers who are pregnant during winter months have an increased risk of delivering babies with neurological issues. Of particular concern is the increase in babies with multiple sclerosis (MS) born in April.
According to research published in the European Journal of Neurology, lack of vitamin D in pregnancy “predisposes” individuals to MS. The Telegraph reports:
Vitamin D, which is largely gained through sunlight and food, is known to regulate a gene that can predispose individuals to MS. If the gene is passed on to the unborn child, without being regulated by a sufficient amount of vitamin D, it could “hard wire” them to develop the disease in later life…
Professor George Ebers, from Oxford University’s department of clinical neurology at the John Radcliffe Hospital, said: “The difference [in developing MS in Scotland] between being born in April versus November is an astounding 50per cent. This is real, there’s no doubt of a seasonal link. There are different theories, but I think the April excess of births could be linked to a sunlight deficiency.
Should parents living in climates that lack winter sun try to conceive at times to avoid winter pregnancies? Researchers believe this may be prudent if there is a family history of neurological disorders, such as MS, but most women can simply take a vitamin D supplement.
Vitamin D has also been shown to be important in preventing the flu.
