Look to physiology and nature
Hansen et al (1) provide further evidence that caesarean section is not without risk to the baby, especially when it is carried out electively before 39 weeks. There are probably a number of reasons why a baby at 37 weeks is more susceptible to respiratory problems after caesarean section than after vaginal delivery. Caesarean delivery will never be physiological and immediate cord clamping is common practice with this form of delivery. Immediate clamping of the cord prevents the normal redistribution of blood in the feto-placental vascular space after delivery. Hypovolaemia of the newborn baby is common. As long ago as 1950, long before antenatal steroids, surfactant or even neonatal ventilation were available, Landau et al (2) working in the USA recognised that respiratory problems after caesarean delivery could be largely prevented by avoiding immediate cord clamping. They used a technique to allow the placental circulation to remain intact till long after delivery. I quote from their paper “Since instituting this technique our results with our cesarean babies have been much better than formerly. For this reason we have not felt justified in running a control series.” How unfortunate that they did not realise the scepticism of their fellow obstetricians and pediatricians would be without a control series, and how many babies’ lives might have been saved if this report had been properly followed up. They go on to say “ in eighty-seven sections done since instituting this technique of placental suspension and drainage, there have been no instances of the previously described syndrome.” ("cyanosis, respiratory distress with dyspnea, air hunger, and costal retraction with weak pulse".)
Although the use of antenatal steroids for elective caesarean section before 39 weeks reduced the risk of admission with RDS in the study by Stutchfield et al (3), overall admissions to special care were not actually significantly reduced, (4) with the result that morbidity, cost, and separation of mother and baby were not affected.
I have called for a trial of physiological management of the cord at elective cesarean section. (5) Based on the evidence of Landau, and more recently Dunn (6), there appears to be the opportunity to prevent respiratory problems after cesarean section without the risks of antenatal steroids. The Cochrane review of delayed cord clamping and a number of studies since have shown the benefit of delayed cord clamping in preterm babies. Indeed there may be an adjunctive effect of antenatal steroids and delayed cord clamping when delivery is necessary well before 39 weeks. Judging by Landau’s results it would not take a very large trial to show benefit.
David J R Hutchon
1. A K Hansen, Wisbourg K, Uldbjerg, T B HenriksenRisk of respiratory morbidity in term infants delivered by elective caesarean section: cohort study BMJ 2007:335
2. Landau D B, Goodrich H B, Franka WF, Burns FR. Journal of Pediatrics (1950) 36:421-426
3. Stutchfield P, Whitaker R, Russell I. Antenatal Betamethasone and incidence of neonatal respiratory distress after elective caesarean section: Pragmatic randomized trial.BMJ 2005:331
4. Stutchfield P R Admissions to Special Care Baby Unit in the Antenatal Steroids for Term Elective Caesarean Section Trial (2005)
5. Hutchon D J R. A trial of physiological delivery at Caesarean (2005)
6. Dunn P M. Reservations about the methods of assessing at birth the predictive value of intrapartum fetal monitoring including premature interruption of the feto-placental circulation. (1986) In Fetal Physiology Measurements. Report of the 2nd International Conference, Oxford, 2-4 April 1984. Ed. P Rolfe. Publ Butterworths, London pp 130-137
Competing interests: No competing interests