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Target rates for caesareans may be too low

But planned caesarean delivery associated with increase in children’s asthma risk by age 5

Louise Prime

Wednesday, 02 December 2015

The World Health Organization’s recommendation that caesarean delivery rates should not exceed 10 to 15 per 100 live births may be too low a target, according to the latest international research* published today in JAMA. In a separate study** also reported in JAMA today, researchers in Aberdeen found that planned caesareans might slightly increase children’s risk of asthma compared with vaginal birth.

Because caesarean delivery – although lifesaving in obstructed labour and other obstetrical emergencies – has risks to both mothers and neonates, WHO has set a recommended target of no more than 10 to 15 per 100 live births to optimise maternal and neonatal outcomes. This was based on previous analyses of its risks and benefits, that had inconsistent results.

US researchers have conducted a new study that looked at data on caesarean rates in 194 WHO member states between 2005 and 2012. They found that overall, the optimal caesarean rate to minimise maternal and neonatal mortality was 19 per 100 live births; and that the estimated current rate is 19.4 per 100. At country level, higher caesarean delivery rates did not correlate with maternal or neonatal mortality.

Looking only at those 76 countries with the best quality information on caesarean delivery rates, the study authors found that rates greater than 6.9 to 20.1 per 100 live births were inversely correlated with the maternal mortality ratio; and rates of 12.6 to 24.0 were inversely correlated with neonatal mortality.
They concluded: “Previously recommended national target rates for caesarean deliveries may be too low.”

Authors of an accompanying editorial*** pointed out that in reality there cannot be one single optimal caesarean rate because of differences between hospitals and healthcare systems, and they argued that whether rates are high or low matters less than delivering “optimal maternal and neonatal care after consideration of all relevant patient and health system information”.

In the second study, researchers led from the University of Aberdeen analysed data on 321,287 term first-born offspring born in Scotland between 1993 and 2007, and followed up until February 2015. They compared outcomes between children born by planned caesarean delivery (3.8%), those born by unscheduled caesarean (17%) and those delivered vaginally (79%).

They found that those born by planned caesarean were at no significantly risk than those born by unscheduled caesarean of several adverse outcomes, including asthma requiring hospital admission, salbutamol inhaler prescription at age 5 years, obesity at age 5 years, inflammatory bowel disease, cancer, or death; but, they were at increased risk of type 1 diabetes (0.66% vs 0.44%).

However, when compared with children born vaginally, those born by planned caesarean had a greater risk of asthma requiring hospital admission (3.73% vs 3.41%), salbutamol inhaler prescription at age 5 years (10.3% vs 9.6%), and death (0.40% vs 0.32%) – but there were no significant differences in these two groups’ risk of obesity at age 5 years, inflammatory bowel disease, type 1 diabetes, or cancer.

They study authors suggested that avoidance of vaginal delivery could be a contributor to rising global rates of asthma, although they acknowledged that the absolute increase in risk was low on an individual level. They said: “Health professionals and women considering planned caesarean delivery should be made aware of this. However, the magnitude of risk is such that in the presence of a medical indication for caesarean delivery, the apparent risk to offspring health is unlikely to justify a plan for vaginal birth.”

* Molina G, Weiser TG, Lipsitz SR et al. Relationship between cesarean delivery rate and maternal and neonatal mortality. JAMA. 2015;314(21):2263-2270. doi:10.1001/jama.2015.15553.

** Black M, Bhattacharya S, Philip S et al. Planned cesarean delivery at term and adverse outcomes in childhood health. JAMA. 2015;314(21):2271-2279. doi:10.1001/jama.2015.16176.

*** D’Alton ME, Hehir MP. Cesarean delivery rates: revisiting a 3-decades-old dogma. JAMA. 2015;314(21):2238-2240. doi:10.1001/jama.2015.15948.

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