Respiratory distress and time of cord clamping
Emmanouilides and Moss (1971) carried out a
second experiment to investigate whether respiratory
distress might be associated with clamping of the
umbilical cord before establishment of respiration [1].
The earlier report by Moss et al. (1963) appeared to
provide evidence of this [2], but drew criticism for
errors in randomization [3, 4].
Randomization in the second study was done by
clamping the cord "early" or "late" on alternate days.
As in the first study, "early clamping" was defined as
that performed before the second breath and "late
clamping" as that after the second breath. The
average time of clamping was 15 seconds after birth
in all but 2 instances for the "early clamped" group,
and 46 seconds for the for the "late clamped" group.
Each group was divided into subgroups because
strict adherence to the protocol could not always be
followed due to individual circumstances. Thus four
groups were defined, I (n=55) and IV (n=15) for early
clamping, and II (n=16) and III (n=61) for late
clamping.
Infants in group II breathed so quickly after birth that
full lung expansion (the second breath) took place
before clamping. Infants in group iV had the cord
clamped before the second breath in 7 cases
because it was deemed hazardous to delay
clamping. In 8 cases the cord was allowed to pulsate
for 1 minute or more but finally clamped before the
second breath because of concern over the delay in
onset of respiration. That the cord was pulsating
should indicate that oxygen was being supplied by
the placenta.
Of the 55 infants in group I (with early clamping per
protocol) 11 were described as "depressed." Of the
61 infants in group III (with late clamping per
protocol) only 2 were depressed.
Respiratory distress developed in 40% of the 55
infants with early cord clamping (13 of 22 with
vaginal delivery, 9 of 22 delivered by c-section).
Respiratory distress developed in 11% of the 61
infants with late cord clamping (6 of 47 with vaginal
delivery, 1 of 7 delivered by c-section). The
difference was noted to be statistically significant
(p=0.005).
In 10 of the early-clamped infants, distress persisted
for more than 24 hours and 3 infants died and were
found to have hyaline membrane disease.
Despite the clear findings reported, Emmanouilides
and Moss did not express the strong opinions voiced
in the papers by Moss et al. (1963) and Moss and
Monset-couchard (1967). They noted that their
findings were at variance with those of Yao et al.
(1969), who reported higher mortality in late-
clamped infants [5].
The paper by Emmanouilides and Moss ends with a
statement, now common in such research, the
further well-controlled observations are needed, with
larger numbers of preterm infants and enforced
randomization. What is this religion of
randomization? A different approach need to be
found, perhaps with experimental animals instead of
human infants, to come to a better understanding of
the process by which an infant's lungs take over the
function of respiration.
(in progress)
- Emmanouilides GC, Moss AJ
(1971) Respiratory distress
in the newborn: effect of cord
clamping before and after
onset of respiration.
- Moss AJ et al. (1963)
Respiratory distress
syndrome in the newborn.
- James LS (1966) Onset of
breathing and resuscitation.
- Sinclair JC (1966)
Prevention and treatment of
the respiratory distress
syndrome.
- Yao AC et al. (1969) Placetal
transfusion in the premature
infant with observation on
clinical course and outcome.
- Emmanouilides GC, Moss AJ. Respiratory distress in the newborn: effect of
cord clamping before and after onset of respiration. Biol Neonate. 1971;18
(5):363-8.
- Moss AJ, Duffie ER Jr, Fagan LM. Respiratory distress syndrome in the
newborn. Study on the association of cord clamping and the pathogenesis
of distress. JAMA. 1963 Apr 6;184:48-50.
- James LS. Onset of breathing and resuscitation. Pediatr Clin North Am.
1966 Aug;13(3):621-34.
- Sinclair JC. Prevention and treatment of the respiratory distress syndrome.
Pediatr Clin North Am. 1966 Aug;13(3):711-30.
- Yao AC, Lind J, Tiisala R, Michelsson K. Placetal transfusion in the
premature infant with observation on clinical course and outcome. Acta
Paediatr Scand. 1969 Nov;58(6):561-6.