Elevation of oxytocin levels early post partum in women

BACKGROUND: The aim of this study was to determine plasma levels of oxytocin in women immediately after delivery. METHODS: Oxytocin was measured in 18 healthy women at 15 minute intervals after normal vaginal deliveries with healthy infants. The mothers had their infants put skin-to-skin on their chests immediately after birth. The infants stayed there up to two hours post partum. RESULTS: There were significant elevations 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 sampled approximately 7-15 minutes before partus. This elevation of oxytocin coincided with the expulsion of placenta. In most women this first elevation was followed by repeated elevations of oxytocin. Oxytocin levels returned to pre partum levels at 60 minutes post partum. CONCLUSIONS: Oxytocin is known to play a role in maternal bonding in animals. Earlier studies indicate that there is a sensitive period for bonding the first hour after giving birth even in women. Our study demonstrates a coincidence of this putative 'sensitive period' and high levels of oxytocin.