something that actually happens quite often is that women forgot about a large part of the childbirth experience, so although they recall it as having been terrible they can't actually remember the exact event from moment to moment. from an evolutionary standpoint, this occurs so that women will want to keep having kids because if they could remember in excruciating detail how horrible it was the first time it occurred, they probably wouldn't want to ever get pregnant again.
fun fact! one of my housemates saw her mom give birth to her sister because her mom thought it would be the sort of thing that was wonderful and educational for her (her parents are really excellent though, just weird sometimes). i think she was maybe 7 or 8 years old at the time. so of course she saw the whole thing including her mom crying and screaming at the nurses and the whole thing with the baby and was essentially reduced to a trembling ball in the corner. the doctors tried to comfort her by saying this was something kids weren't really supposed to ever see and she was very brave.
so, her mom forgot most of the experience and only vaguely recalls it as having been painful, but of course my housemate has the whole thing stamped in her memory in detail and now, like me, has a massive phobia of having kids as a result of this experience. at least i'm not alone.