The 1950 edition of William's Obstetrics provides the following comment:
"Clamping or ligating the umbilical cord should be deferred
until its pulsations wane or, at least, for one or two minutes."
"There has been a tendency of late, for a number of reasons, to
ignore this precept. In the first place the widespread use of
analgesic drugs in labor has resulted in a number of infants
whose respiratory efforts are sluggish at birth and whom the
obstetrician wishes to turn over immediately to an assistant for
aspiration of mucus, and if necessary, resuscitation. This
readily leads to the habit of clamping all cords promptly."
Eastman HJ (1950) Williams Obstetrics, Tenth Edition, pp 397-398