I suspect that this is a load of total baloney!
It might have happened in the past - there was something called Twilight Sleep, where women were given a powerful drug that not only provided analgesia during childbirth, it also erased the memory of birth altogether.
It used morphine and scopolamine, but the latter had some pretty horrific side effects, according to this article:
"Scopolamine caused women to lose their inhibitions, and have no conscious awareness of what was happening to them. The small amount of morphine used didn’t prevent pain, but contributed to women becoming uninhibited, and even psychotic. Many women would thrash around, bang their heads on walls, claw at themselves or staff, and scream constantly. They would either be restrained on their beds, by their wrists and ankles, or put into straight jackets.
Often blinded by towels wrapped around their heads to prevent injury, they would be put into ‘labour cribs’ – cot-like beds that prevented them from falling to the floor. They would remain on the beds, bound and screaming, often lying in their own vomit and waste, for as long as it took for labour to end."
This practice was used in the early years of the 20th century, but soon fell out of favour, due to the side effects, and risks to the baby.
I highly doubt that any obstetrician would perform a caesarian unless it was medically necessary.