It is standard procedure in some hospitals to administer a strong sedative/IV Narcotic once the baby is out. This can really knock a mom out for hours, and she will have hazy/no memory of the surgery itself, and potentially not be mentally *present* to meet the baby in recovery. Since the "putting everything back together" part is the long part of the surgery, having you sedated is easier on the surgeon & staff.
I have had some clients specifically request no sedative after the baby is out, and gotten that agreed to, and some were simply ignored and drugged anyway.
Every hospital's protocols are different, so you may need to talk to the anesthesia dept directly to get the scoop on yours.