Bon, artificial oxytocin (syntocinon) use in labour can increase the risk of PPH. This is from Sarah Buckley's article on the natural approach to third stage of labour, in the birth section:

"Other western practices that may contribute to PPH include the use of oxytocin for induction and augmentation (speeding up labour)28 29 episiotomy or perineal trauma, forceps delivery, caesarean and previous caesarean (because of placental problems- see Hemminki30).

Gilbert notes that PPH rates in her UK hospital more than doubled from 5% in 1969-70 to 11% in 1983-5, and concludes, 'The changes in labour ward practice over the last 20 years have resulted in the re-emergence of PPH as a significant problem.'31 In particular, she links an increased risk of bleeding with induction using oxytocin, forceps delivery, long first and second stages (but not prolonged pushing) and the use of epidurals, which increase the chance of forceps and of a long second stage."