Fig. 3

a Oxytocin levels in physiological labour. Means from samples collected 5 times from 17 women over the duration of first stage. Note that peaks are not observed because samples were collected at long intervals. Adapted from Fuchs 1983 [23]. b Oxytocin levels with synthetic oxytocin infusion. Means from samples collected 5 times from 15 women induced with synthetic oxytocin. Samples were collected, as indicated by arrows, before infusion begun at 1-3 mU/min, and at the end of each infusion period (before the next increase). Adapted from Fuchs 1983 [23]