NEW YORK (Reuters Life!) - Preterm birth, and even early term birth, may put babies at higher risk for needing asthma medication during childhood and adolescence, according to a Swedish study.
"Every week in the womb is important for the fetus in order to reduce the risk of childhood asthma," said Hartmut Vogt from Linkoping University in Sweden, who worked on the study, published in "Pediatrics."
"The induction of delivery before term, e.g. by cesarean section, should be avoided whenever possible," he told Reuters Health by email.
Vogt and his colleagues used data from national health and prescription registries to examine the potential effect of gestational age on the need for inhaled corticosteroids (ICS), as a symbol of asthma, in children aged 6 to 19 years.
In 2006, 4.9 percent of boys and 3.8 percent of girls had filled prescriptions for corticosteroids, whose use declined with increasing age in boys but increased slightly for females born at term.
A pregnancy is considered "at term" after 37 complete weeks.
The likelihood of using the drugs was higher in all categories of gestational age below 39 weeks compared with term infants, and it increased with the degree of immaturity. This was true of both boys and girls.
Although cesarean delivery and hospitalization for respiratory syncytial virus (RSV) contributed to the increased rate of corticosteroid use, the association between gestational age and steroid use persisted even after adjusting for these factors.
"We were quite surprised when we found that even children born in week 37-38 had a slightly increased risk of asthma medication when compared with children born at term," Vogt said.
"On the other hand, it seems quite reasonable to believe that the gradual development of the lungs might influence the risk for asthma in a similar way."
Vogt added that the effects of an early birth appeared to be relieved by increasing age, indicating perhaps that asthma symptoms related to early preterm birth wane in older children.
A different Swedish study earlier this year found a relationship between very premature birth -- between weeks 23 and 27 -- and asthma in young adulthood, but no increased risk for babies with at least 27 weeks of gestation. SOURCE: bit.ly/mOPskW
Reporting by Will Boggs at Reuters Health; editing by Elaine Lies