C-section babies, asthma linked
2008-12-02 10:27
London - Babies born by Caesarean
section are more likely to develop asthma than children
delivered naturally, Swiss researchers said on Tuesday.
There has been conflicting evidence on the link between
asthma and C-sections but the researchers said the number of
children involved in their study and a long monitoring period
strengthened their results.
The findings also underscore the potential risks of
elective C-sections as more women in Western countries choose
to avoid a natural birth, the researchers said in the medical
journal, Thorax.
"The increased rate of Caesarean section is partly due to
maternal demand without medical reason," Caroline Roduit of
Kinderspital Zurich medical institution and colleagues wrote.
"In this situation the mother should be informed of the
risk of asthma for her child, especially when the parents have
a history of allergy or asthma."
Asthma, which affects more than 300 million people
worldwide, is the most common paediatric chronic illness.
Symptoms include wheezing, shortness of breath, coughing and
chest tightness.
Babies born by C-section are not exposed to their mother's
bacteria when they pass through the birth canal - something
that helps prime the immune system and could explain the
increased risk, the researchers said.
The Swiss findings are based on nearly 3 000 children whose
respiratory health was monitored until age eight. By this time,
about 12%, or 362 children, had been diagnosed with
asthma for which a doctor had prescribed inhaled steroids.
About 9% of the children were born by C-section but
these babies were nearly 80% more likely to develop
asthma compared to those born vaginally, the researchers said.
The association was even stronger for the 9% of the
children with two allergic parents who were already more
predisposed to the respiratory condition, they wrote.
The findings follow a Norwegian study in July suggesting
babies born by C-section have a moderately increased asthma
risk. Other studies have found no link between C-sections and a
child's long-term health, including asthma.