March 1st, 2010 
Mothers who smoke during pregnancy put their children at greater risk of developing psychotic symptoms as teenagers, British scientists said on Thursday.
Researchers from four British universities studied 6,356 12-year-olds and interviewed them for psychotic-like symptoms such as hallucinations or delusions. Around 19 percent had mothers who smoked during pregnancy.
Just over 11 percent, or 734 of the total group, had suspected or definite symptoms of psychosis.
Many previous studies have shown cigarettes can harm the fetuses of mothers who smoke while pregnant. The risks include causing babies to be born smaller and increasing the risk of sudden infant death syndrome or heart defects.
Stanley Zammit, a psychiatrist at Cardiff University’s School of Medicine who led the study, said the more the mothers smoked, the more likely their children were to have psychotic symptoms.
“We can estimate that about 20 percent of adolescents in this cohort would not have developed psychotic symptoms if their mothers had not smoked,” he said.
Despite countless studies flagging up the risks to babies, it is estimated that between 15 and 20 percent of women in Britain smoke during pregnancy.
The researchers also found drinking during pregnancy was associated with increased psychotic symptoms, but only in children whose mothers had drunk more than 21 units of alcohol a week in early pregnancy.
The reasons for the link between maternal smoking and psychotic symptoms are not clear, but Zammit and colleagues suggested that exposure to tobacco in the womb might affect a child’s impulsivity, attention or cognition.
Only a few mothers in the study, which was published in the British Journal of Psychiatry, said they had smoked cannabis during pregnancy, and this was not found to have any significant link with psychotic symptoms.
Related
- Smoking in pregnancy risks psychotic children
Mothers who smoke during pregnancy put their children at greater risk of developing psychotic symptoms as teenagers, British scientists said on Thursday.
Researchers from four British universities studied 6,356 12-year-olds and interviewed them for psychotic-like symptoms such as hallucinations or delusions. Around 19 percent had mothers who smoked during pregnancy.
Just over 11 percent, or 734 of the total group, had suspected or definite symptoms of psychosis.
Many previous studies have shown cigarettes can harm the fetuses of mothers who smoke while pregnant. The risks include causing babies to be born smaller and increasing the risk of sudden infant death syndrome or heart defects.
Stanley Zammit, a psychiatrist at Cardiff University’s School of Medicine who led the study, said the more the mothers smoked, the more likely their children were to have psychotic symptoms.
“We can estimate that about 20 percent of adolescents in this cohort would not have developed psychotic symptoms if their mothers had not smoked,” he said.
Despite countless studies flagging up the risks to babies, it is estimated that between 15 and 20 percent of women in Britain smoke during pregnancy.
The researchers also found drinking during pregnancy was associated with increased psychotic symptoms, but only in children whose mothers had drunk more than 21 units of alcohol a week in early pregnancy.
The reasons for the link between maternal smoking and psychotic symptoms are not clear, but Zammit and colleagues suggested that exposure to tobacco in the womb might affect a child’s impulsivity, attention or cognition.
Only a few mothers in the study, which was published in the British Journal of Psychiatry, said they had smoked cannabis during pregnancy, and this was not found to have any significant link with psychotic symptoms.
- Smoking During Pregnancy Linked to Behavioral Problems in Children
New research set to be published in the Journal of Epidemiology and Community Health suggests that mothers who smoke while pregnant are essentially toying with the brain chemistry of their future children.
“There are 4000 toxic substances in cigarette smoke, and many of these will pass into the brain of the fetus, and it is possible that they could have an effect on how the brain chemistry works,” said Professor Alan Maryon-Davis, president of the Faculty of Public Health, to the BBC.
The research involved more than 14,000 pairs of mothers and their children, all participants in the Millennium Cohort Study, a study that focused on children born in the U.K. between 2000 and 2001.
First, mothers were put into categories based upon the amount of cigarettes they smoked during pregnancy. Then, using a validated questionnaire called Strengths and Difficulties, mothers were asked to grade their children’s level of hyperactivity, type of temperament, frequency of fights, and ease of distraction. Taking into account factors that might influence the results, including socioeconomic status, mother’s age, and level of education, the researchers began analyzing the data.
It was found that nearly one in ten women smoked heavily during pregnancy, 12.5 percent smoked lightly during pregnancy, and 12.4 percent said they stopped smoking while pregnant.
Boys of mothers who smoked heavily while pregnant were almost twice as likely to have behavioral problems, while boys of mothers who smoked lightly while pregnant had an 80 percent increased likelihood of having an attention deficit disorder.
Researchers found a significant increase in likelihood that those girls of mothers who smoked lightly or heavily had conduct issues.
“Smoking during pregnancy may damage the developing structure and function of the fetal brain, which has already been shown to be the case in animals”, said the authors.
“The fetal development of boys may also be more sensitive to this kind of chemical assault, which might explain why boys are more likely to have behavioral problems than girls.”
- 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.
- 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.
- Pot smoking during pregnancy may stunt fetal growth
Women who smoke marijuana during pregnancy may impair their baby’s growth and development in the womb, a new study suggests.
Poor fetal growth and reduced head circumference at birth are linked to an increased risk of problems with thinking, memory and behavior in childhood. Cigarette smoking during pregnancy is known to impair fetal growth, but studies on the potential effects of marijuana have been inconclusive.
For the new study, researchers in the Netherlands followed more than 7,000 pregnant women, 3 percent of whom acknowledged smoking marijuana at least during early pregnancy. They found that babies born to marijuana users tended to weigh less and have smaller heads than other infants.
What’s more, the study found, the longer a woman had used marijuana during pregnancy, the stronger the impact on birth size – suggesting that the drug itself was to blame.
And while most marijuana users in the study also smoked cigarettes, the drug appeared to have effects over and above those of tobacco. In fact, marijuana showed stronger effects on birth size than tobacco, the investigators report in the Journal of the American Academy of Child and Adolescent Psychiatry.
The findings suggest that marijuana use, even restricted to early pregnancy, may have irreversible effects on fetal growth, write the researchers, led by Hannan El Marroun of Erasmus University Medical Center in Rotterdam.
The study included almost 7,500 pregnant women who were surveyed on their use of alcohol, tobacco and drugs, and had ultrasounds to chart fetal growth during the first, second and third trimesters.
Overall, 214 women said they had used marijuana before and during early pregnancy; 81 percent quit after learning they were pregnant, but 41 women continued to smoke marijuana throughout pregnancy.
The researchers found that, on average, marijuana users gave birth to smaller babies, particularly those who had used throughout pregnancy.
Women who had smoked only during early pregnancy had babies who were 156 grams — about 5.5 ounces — lighter than infants born to women who had not used the drug. Women who had continued to smoke past early pregnancy had babies who were 277 grams, or nearly 10 ounces, smaller.
Based on ultrasound, marijuana use only in early pregnancy impaired fetal growth by about 11 grams per week, while use throughout pregnancy slowed fetal growth by roughly 14 grams per week. That compared with a deficit of 4 grams per week with tobacco use, the researchers found.
Similar patterns were seen when the researchers looked at fetal head circumference.
According to El Marroun’s team, mothers’ marijuana use could stunt fetal growth for several reasons. Like tobacco smoking, it may deprive the fetus of oxygen. It is also possible that the byproducts of marijuana directly affect the developing nervous and hormonal systems of the fetus.
Finally, the researchers note, pregnant women who use marijuana may have other factors in their lives – such as a less-than-healthy diet or chronic stress — that could contribute to poor fetal growth.
