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in a Danish birth cohort study.
The reason behind the correlation is unclear. Maternal infections, rather than antibiotics, “could explain the observed association,” said study author Cecilie Skaarup Uldbjerg, a researcher in the department of public health at Aarhus University in Denmark.
Still, the “results are in keeping with the hypothesis that effects of antibiotics impact the maternally derived microbiome in vaginally born children and that this may increase the odds of childhood asthma,” Ms. Uldbjerg and coauthors wrote in their study, which was published online Feb. 9 in Archives of Disease in Childhood . “However, this observational study did not address underlying mechanisms, and this interpretation, while plausible, remains speculative.”
Antibiotic use in pregnancy likely to continue
Patrick Duff, MD, who was not involved in the research, does not expect the findings will alter clinical practice.
The association was relatively weak, and the study does not account for factors such as antibiotic exposure during early childhood or tobacco smoke in the house, said Dr. Duff, professor of maternal-fetal medicine at University of Florida, Gainesville.
“Although I agree that we should not use antibiotics indiscriminately during pregnancy, we definitely need to treat certain infections,” Dr. Duff said. “Thus we cannot avoid some degree of antibiotic exposure.”
Although prior research has indicated that antibiotic use in pregnancy may increase the risk of asthma in children, results have been inconsistent.
To study whether antibiotic exposure during pregnancy is associated with childhood asthma and whether the timing of antibiotic exposure or mode of delivery influence the relationship, the investigators analyzed data from more than 32,000 children in the Danish National Birth Cohort, which was established in 1996.
Children of mothers who took and did not take antibiotics compared
In all, 17% of the children were born to mothers who used antibiotics during pregnancy. Compared with mothers who did not take antibiotics, those who did reported more maternal asthma, smoking during pregnancy, and having overweight or obesity. In addition, they were less likely to have been in their first pregnancy.
During follow-up at age 11 years, 4,238 children (13%) had asthma, including 12.7% of those whose mothers had not been exposed to antibiotics, and 14.6% of those whose mothers had used antibiotics during pregnancy.
In adjusted analyses, children born to mothers who received antibiotics were more likely to have asthma (OR, 1.14).
Antibiotic exposure in the second to third trimester, but not in the first trimester, was associated with asthma. The association was observed in vaginally born children, but not in children born by cesarean section.
The study is limited by its reliance on maternal reporting for data about antibiotics and asthma diagnoses, the authors noted. Mothers completed telephone interviews twice during pregnancy and once at 6 months postpartum. They completed online questionnaires to provide follow-up information at 11 years.
Mode of delivery may matter
The researchers said their analysis indicates that mode of delivery may modify the association between antibiotic exposure during pregnancy and childhood asthma.
Fourteen percent of the children in the study were delivered by cesarean section. Further research may clarify the relationship between antibiotics in pregnancy, mode of delivery, and asthma risk, another doctor who was not involved the study added.
“I do not think that the evidence indicates that mode of delivery clearly has an impact,” said Santina J. G. Wheat, MD, MPH, associate professor of family and community medicine at Northwestern University in Chicago, “as the number of cesarean deliveries was not large enough to fully support such a statement.
“It will be interesting to see if an association holds in future studies with increased cesarean deliveries,” Dr. Wheat said.
How and why antibiotics were used may be other important factors to investigate, Dr. Duff suggested.
“The authors did not provide any specific information about which antibiotics were used by the mothers, duration of use, and indication for use. Those are very important confounders,” Dr. Duff said. “Perhaps the key exposure is to a particular maternal infection rather than to the antibiotic per se.”
The Danish National Birth Cohort was established with a grant from the Danish National Research Foundation and support from regional committees and other organizations. Its biobank has been supported by the Novo Nordisk Foundation and the Lundbeck Foundation, and follow-up of mothers and children has been supported by the Danish Medical Research Council, the Lundbeck Foundation, Innovation Fund Denmark, the Nordea Foundation, Aarhus Ideas, a University of Copenhagen strategic grant, and the Danish Council for Independent Research. The study was partially funded by the Health Research Fund of Central Denmark Region, which supported one of the authors. Other authors were supported by the DHB Foundation and the Australian National Health and Medical Research Council. One author is affiliated with Murdoch Children’s Research Institute in Australia, where the Victorian Government’s Operational Infrastructure Support Program supports research.
The authors had no competing interests. Dr. Wheat serves on the editorial advisory board of Family Practice News. Dr. Duff had no relevant financial disclosures.
in a Danish birth cohort study.
The reason behind the correlation is unclear. Maternal infections, rather than antibiotics, “could explain the observed association,” said study author Cecilie Skaarup Uldbjerg, a researcher in the department of public health at Aarhus University in Denmark.
Still, the “results are in keeping with the hypothesis that effects of antibiotics impact the maternally derived microbiome in vaginally born children and that this may increase the odds of childhood asthma,” Ms. Uldbjerg and coauthors wrote in their study, which was published online Feb. 9 in Archives of Disease in Childhood . “However, this observational study did not address underlying mechanisms, and this interpretation, while plausible, remains speculative.”
Antibiotic use in pregnancy likely to continue
Patrick Duff, MD, who was not involved in the research, does not expect the findings will alter clinical practice.
The association was relatively weak, and the study does not account for factors such as antibiotic exposure during early childhood or tobacco smoke in the house, said Dr. Duff, professor of maternal-fetal medicine at University of Florida, Gainesville.
“Although I agree that we should not use antibiotics indiscriminately during pregnancy, we definitely need to treat certain infections,” Dr. Duff said. “Thus we cannot avoid some degree of antibiotic exposure.”
Although prior research has indicated that antibiotic use in pregnancy may increase the risk of asthma in children, results have been inconsistent.
To study whether antibiotic exposure during pregnancy is associated with childhood asthma and whether the timing of antibiotic exposure or mode of delivery influence the relationship, the investigators analyzed data from more than 32,000 children in the Danish National Birth Cohort, which was established in 1996.
Children of mothers who took and did not take antibiotics compared
In all, 17% of the children were born to mothers who used antibiotics during pregnancy. Compared with mothers who did not take antibiotics, those who did reported more maternal asthma, smoking during pregnancy, and having overweight or obesity. In addition, they were less likely to have been in their first pregnancy.
During follow-up at age 11 years, 4,238 children (13%) had asthma, including 12.7% of those whose mothers had not been exposed to antibiotics, and 14.6% of those whose mothers had used antibiotics during pregnancy.
In adjusted analyses, children born to mothers who received antibiotics were more likely to have asthma (OR, 1.14).
Antibiotic exposure in the second to third trimester, but not in the first trimester, was associated with asthma. The association was observed in vaginally born children, but not in children born by cesarean section.
The study is limited by its reliance on maternal reporting for data about antibiotics and asthma diagnoses, the authors noted. Mothers completed telephone interviews twice during pregnancy and once at 6 months postpartum. They completed online questionnaires to provide follow-up information at 11 years.
Mode of delivery may matter
The researchers said their analysis indicates that mode of delivery may modify the association between antibiotic exposure during pregnancy and childhood asthma.
Fourteen percent of the children in the study were delivered by cesarean section. Further research may clarify the relationship between antibiotics in pregnancy, mode of delivery, and asthma risk, another doctor who was not involved the study added.
“I do not think that the evidence indicates that mode of delivery clearly has an impact,” said Santina J. G. Wheat, MD, MPH, associate professor of family and community medicine at Northwestern University in Chicago, “as the number of cesarean deliveries was not large enough to fully support such a statement.
“It will be interesting to see if an association holds in future studies with increased cesarean deliveries,” Dr. Wheat said.
How and why antibiotics were used may be other important factors to investigate, Dr. Duff suggested.
“The authors did not provide any specific information about which antibiotics were used by the mothers, duration of use, and indication for use. Those are very important confounders,” Dr. Duff said. “Perhaps the key exposure is to a particular maternal infection rather than to the antibiotic per se.”
The Danish National Birth Cohort was established with a grant from the Danish National Research Foundation and support from regional committees and other organizations. Its biobank has been supported by the Novo Nordisk Foundation and the Lundbeck Foundation, and follow-up of mothers and children has been supported by the Danish Medical Research Council, the Lundbeck Foundation, Innovation Fund Denmark, the Nordea Foundation, Aarhus Ideas, a University of Copenhagen strategic grant, and the Danish Council for Independent Research. The study was partially funded by the Health Research Fund of Central Denmark Region, which supported one of the authors. Other authors were supported by the DHB Foundation and the Australian National Health and Medical Research Council. One author is affiliated with Murdoch Children’s Research Institute in Australia, where the Victorian Government’s Operational Infrastructure Support Program supports research.
The authors had no competing interests. Dr. Wheat serves on the editorial advisory board of Family Practice News. Dr. Duff had no relevant financial disclosures.
in a Danish birth cohort study.
The reason behind the correlation is unclear. Maternal infections, rather than antibiotics, “could explain the observed association,” said study author Cecilie Skaarup Uldbjerg, a researcher in the department of public health at Aarhus University in Denmark.
Still, the “results are in keeping with the hypothesis that effects of antibiotics impact the maternally derived microbiome in vaginally born children and that this may increase the odds of childhood asthma,” Ms. Uldbjerg and coauthors wrote in their study, which was published online Feb. 9 in Archives of Disease in Childhood . “However, this observational study did not address underlying mechanisms, and this interpretation, while plausible, remains speculative.”
Antibiotic use in pregnancy likely to continue
Patrick Duff, MD, who was not involved in the research, does not expect the findings will alter clinical practice.
The association was relatively weak, and the study does not account for factors such as antibiotic exposure during early childhood or tobacco smoke in the house, said Dr. Duff, professor of maternal-fetal medicine at University of Florida, Gainesville.
“Although I agree that we should not use antibiotics indiscriminately during pregnancy, we definitely need to treat certain infections,” Dr. Duff said. “Thus we cannot avoid some degree of antibiotic exposure.”
Although prior research has indicated that antibiotic use in pregnancy may increase the risk of asthma in children, results have been inconsistent.
To study whether antibiotic exposure during pregnancy is associated with childhood asthma and whether the timing of antibiotic exposure or mode of delivery influence the relationship, the investigators analyzed data from more than 32,000 children in the Danish National Birth Cohort, which was established in 1996.
Children of mothers who took and did not take antibiotics compared
In all, 17% of the children were born to mothers who used antibiotics during pregnancy. Compared with mothers who did not take antibiotics, those who did reported more maternal asthma, smoking during pregnancy, and having overweight or obesity. In addition, they were less likely to have been in their first pregnancy.
During follow-up at age 11 years, 4,238 children (13%) had asthma, including 12.7% of those whose mothers had not been exposed to antibiotics, and 14.6% of those whose mothers had used antibiotics during pregnancy.
In adjusted analyses, children born to mothers who received antibiotics were more likely to have asthma (OR, 1.14).
Antibiotic exposure in the second to third trimester, but not in the first trimester, was associated with asthma. The association was observed in vaginally born children, but not in children born by cesarean section.
The study is limited by its reliance on maternal reporting for data about antibiotics and asthma diagnoses, the authors noted. Mothers completed telephone interviews twice during pregnancy and once at 6 months postpartum. They completed online questionnaires to provide follow-up information at 11 years.
Mode of delivery may matter
The researchers said their analysis indicates that mode of delivery may modify the association between antibiotic exposure during pregnancy and childhood asthma.
Fourteen percent of the children in the study were delivered by cesarean section. Further research may clarify the relationship between antibiotics in pregnancy, mode of delivery, and asthma risk, another doctor who was not involved the study added.
“I do not think that the evidence indicates that mode of delivery clearly has an impact,” said Santina J. G. Wheat, MD, MPH, associate professor of family and community medicine at Northwestern University in Chicago, “as the number of cesarean deliveries was not large enough to fully support such a statement.
“It will be interesting to see if an association holds in future studies with increased cesarean deliveries,” Dr. Wheat said.
How and why antibiotics were used may be other important factors to investigate, Dr. Duff suggested.
“The authors did not provide any specific information about which antibiotics were used by the mothers, duration of use, and indication for use. Those are very important confounders,” Dr. Duff said. “Perhaps the key exposure is to a particular maternal infection rather than to the antibiotic per se.”
The Danish National Birth Cohort was established with a grant from the Danish National Research Foundation and support from regional committees and other organizations. Its biobank has been supported by the Novo Nordisk Foundation and the Lundbeck Foundation, and follow-up of mothers and children has been supported by the Danish Medical Research Council, the Lundbeck Foundation, Innovation Fund Denmark, the Nordea Foundation, Aarhus Ideas, a University of Copenhagen strategic grant, and the Danish Council for Independent Research. The study was partially funded by the Health Research Fund of Central Denmark Region, which supported one of the authors. Other authors were supported by the DHB Foundation and the Australian National Health and Medical Research Council. One author is affiliated with Murdoch Children’s Research Institute in Australia, where the Victorian Government’s Operational Infrastructure Support Program supports research.
The authors had no competing interests. Dr. Wheat serves on the editorial advisory board of Family Practice News. Dr. Duff had no relevant financial disclosures.
FROM ARCHIVES OF DISEASE IN CHILDHOOD