I had a 4.5 hour 1st labour, and my placenta took just under 20 minutes to deliver. I had a jab (can't remember being consulted about that) and it was amidst loads of uncomfortable tugging by the midwife. ('Till I told her to 'LEAVE IT!'
I'm having a homebirth this time, and I've spoken with my midwife about it, and we're going to go with breastfeeding rather than a jab this time. I breastfed last time, and she doesn't feel the procedures they used to remove the placenta were warranted in my case, but more down to the hospitals policy.