Bnckground. The aim of this study was to determine plasma levels of ox
ytocin in women immediately after delivery. Methods. Oxytocin was meas
ured in 18 healthy women at 15 minute intervals after normal vaginal d
eliveries with healthy infants. The mothers had their infants put skin
-to-skin on their chests immediately after birth, The infants stayed t
here up to two hours post partum. Results. There were significant elev
ations of oxytocin 15, 30 and 45 minutes after delivery (p=0.007, 0.02
and 0.02 respectively) when compared with average pre partum levels s
ampled approximately 7-15 minutes before partus. This elevation of oxy
tocin coincided with the expulsion of placenta. In most women this fir
st elevation was followed by repeated elevations of oxytocin. Oxytocin
levels returned to pre partum levels at 60 minutes post partum. Concl
usions. Oxytocin is known to play a role in maternal bonding in animal
s. Earlier studies indicate that there is a sensitive period for bondi
ng the first hour after giving birth even in women. Our study demonstr
ates a coincidence of this putative 'sensitive period' and high levels
of oxytocin.