Big disadvantage is that it rushes the natural process and *from my experiences and research* you are more prone to a retained placenta (ironically) if you do this. If the body is left to be, the process is that the cord continues to pulsate, all the blood is delivered to the baby, after which, the placenta knows its done its job, as a hormone is released, which makes the placenta detatch from the uterus. Breastfeeding triggers the uterine contractions too.

Yes the synto has its place, if you look like you are starting to haemorrage, it is important to have it. If the placenta doesn't look like budging after about half an hour after the cord has finished pulsating, you should look into having it. It doesn't need to be routinely given in a normal birth however, as the body has its own processes for delivering the placenta. Meddle with this and its just screwing with the natural process and you might run into more problems than you solve.

For most people it might not have any negative effects, but it also might not have any positive effect either.

I hope this has helped you make an informed choice on the matter .