i was offered this with my recent c-section. at first i was keen (41, 3rd child definitely last), however i changed my mind. reasons were
1- there is a high failure rate (higher than vasectomy)if done during c-section, and if you do get pregnant again, then there is a high chance the pregnancy could be ectopic.
2- i decided that i wanted the section to be about the birth of ds, and nothing else, especially not the end of childbearing, iyswim!
3- i wanted to be clear about what i was recovering from, ie i didn't want to be feeling wierd a month after the birth and wondering whether it was the birth or the sterilisation.
as it was i was very glad that i didn't have it done. i had a more complicated section than had been predicted, because i was allergic to the pain meds, and my bp went very low, so the op was done on a tilt. i don't think they would have the sterilisation, and if they had it would have complicated things imo.
fortunately after seeing me go through this, dh has agreed to have a vasectomy
!
good luck with your decision.