Ellen, I have not seen a formal study but at the hospital I work in I haven't noticed a relationship with pitocin and late onset of milk, I would be more suspicious of the epidural. On a personal note, I was augmented with Pitocin with both of my children the first one for 8 hours and the 2nd for 1.5 hours. I had demerol with the first and an epidural withe the 2nd (i only had the epidural for 1.5hours and my milk came in with bothe children 2 days post-partum. Caren Goldstein RNC IBCLC