The goal of the study was to investigate the possible link between being born by Caesarean section and later development of asthma.
Summarised results from the study:
Compared to children born in the natural way (i.e. spontaneously and vaginally), children born by Caesarean section had an approximately 50 % increased risk of developing asthma.
Children born vaginally, but with assistance from vacuum or forceps, had a 20 % increased risk of asthma.
For children born between 1988 and 1998, planned Caesarean section was associated with an approximately 40 % increased risk of asthma while emergency Caesarean section was associated with a 60 % increased risk.
Why do Caesarean sections give an increased risk of asthma?
"The first is that babies who are born by Caesarean section are not exposed to their mothers’ bacteria during birth, which is detrimental for development of the immune system. The other is that babies born by Caesarean section have more breathing problems after birth because they are less exposed to stress hormones and compression of the chest, since these mechanisms contribute to emptying the lungs of amniotic fluid. Maybe this can negatively affect lung function in the long term
United States Sees Steep Rise In 'No Indicated Risk' Caesareans
The United States has seen a steep rise in caesareans to women with no reported medical risk, according to research published today on bmj.com
Results showed that caesarean rates increased by 67% among these mothers. First-time mothers aged 34 and over were the most likely to have a 'no indicated risk' caesarean, with almost 1 in 5 giving birth by caesarean in 2001.
Caesarean births also rose steeply for 'no indicated risk' mothers under 30, increasing by 58% between 1991 and 2001. For first-time mothers over 40, the odds of having a 'no indicated risk' caesarean were over 5 times that for mothers aged 20-24.
Undergoing caesareans where there is no reported medical indication raises serious questions, say the authors, not least for younger mothers who plan to have further children. More research is needed on whether the risks associated with surgery outweigh the benefits in these circumstances, they conclude.
