Asthma may be linked to a slight increase in preterm birth, a study of registry data from Sweden suggests.
The study found a 5.4% rate of preterm birth among 13 261 mothers with asthma, compared to 4.4% in 111,931 non-asthmatic mothers. The risk was particularly increased in women with exacerbations of their asthma during pregnancy. Mothers with asthma may be able to reduce their risk by managing their disease, according to experts.
"Well-managed asthma is far less likely to result in a preterm delivery," said Dr Bertil Forsberg, of Umea University, who led the study. Dr Forsberg and his team presented their results at the European Respiratory Society's annual meeting in Vienna, Austria.
How the study was done
They calculated that the odds ratio for giving birth preterm is 1.27 for women with asthma.
The difference was statistically significant after logistic regression modelling accounting for variables such as education, previous preterm birth, origin, number of births, date of conception and maternal age.
Nearly 2% of the women with asthma visited the hospital to treat asthma symptoms at least once during their pregnancy, and they had a higher rate of preterm birth at 8.4%.
Optimise your asthma control
A possible explanation for the higher rate may be that inflammatory responses associated with severe asthma could affect the placenta, especially in early pregnancy, Dr Fosberg says.
Dr Fosberg also suggests that asthmatic mothers may be more susceptible to air pollution and viral infections.
Dr Meilan Han, who directs the Women's Respiratory Health Program at the University of Michigan and was not involved in the research, said the data strengthen findings from prior studies and are not surprising.
"It is important that asthmatic mothers be aware that their risk for preterm delivery likely is slightly increased," Dr Han said.
"All too often, asthmatic women stop their asthma medication in an effort 'to protect' the baby," Dr Han added. "As this study emphasises, the health of the mother is directly proportional to the health of the baby. While not specifically addressed in this abstract, in general, prenatal complications are reduced when maternal asthma is adequately controlled. Therefore, the important message for women with asthma who are pregnant or are thinking about becoming pregnant is that they must work with their doctor to optimise their asthma control in order to achieve the best possible outcome for their pregnancy."
(Reuters Health, September 2012)
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