Babies born by caesarean are
nearly three times more likely to die in the
first month than those born naturally, US
research shows.
The findings, based on over
5.7 million births, are particularly important
given the growing trend of women opting for
caesareans, say the authors.
More than one in five of
all British babies are now born by caesarean.
The Birth journal study included
women with no obvious medical risks who had
elected to have a caesarean.
Higher risk
Even after adjusting the
results for social and medical differences
among the women, babies born by caesarean
were still at more than twice the risk of
dying in the first month of life.
From 1998 to 2001, the death
rate among those delivered by caesarean was
1.77 per 1,000 live births compared to 0.62
for vaginal deliveries.
Generally, neonatal deaths
are rare for low-risk women, in the order
of one death per 1,000 live births, according
to the lead researcher Dr Marian MacDorman
of the Centers for Disease Control and Prevention.
However, the study only include
babies that were born alive, which the researchers
said would change the results.
Had stillbirths been included,
the risk of vaginal deliveries would have
been closer to that of caesarean deliveries.
Also, the deliveries in the
study ranged from 37 weeks' gestation to full-term
or 41 weeks.
In the UK, planned caesarean
sections are performed after 39 weeks' gestation
because it is known that deliveries earlier
than this carry a higher risk to the baby.
And the risks of both types
of delivery are still extremely small.
Explanation
The researchers suggest that
the process of labour helps prepare the baby
for life outside of the womb.
As well as squeezing fluid
out of the lungs, it may promote the release
of hormones that encourage healthy lung function.
Dr MacDormac said: "Labour
is an important part of the birthing process
because it gets infants ready to breathe air
and function outside the womb."
Professor James Walker, consultant
obstetrician at St James's University Hospital
in Leeds and spokesman for the Royal College
of Obstetricians and Gynaecologists, said
women should not be alarmed by the findings
but should be informed.
"The absolute risk is still
very small.
"But it should open people
up to the fact that there are risks and benefits
of everything. This is a relatively small
risk but it is there and people need to know
that."
Belinda Phipps of the National
Childbirth Trust said: "I think that the study
does need to be taken pretty seriously."
She said that earlier studies
had already hinted that babies born by caesarean
are more likely to experience breathing problems.
