I know of two women who deliberately got pregnant, whilst their partner thought that they were on contraception. One faked she was on the pill claiming she never ever wanted children. Another said she medically couldn't have children.
Both cases were because they wanted a baby, and someone to pay their bills, they weren't in relationships, and approaching 40. Figured they'd just get pregnant, act surprised, and the man would stay out of obligation. They aren't even shy about admitting it. The one who faked being on the pill, is now a single mother, from birth. The one who faked she couldn't have children is a single mother, father left when child was 3 months. Both trash talk the father's for leaving them the child.
Both genuinely think they've been really clever, now getting their child support and child related benefits every month. Neither work. Children are school age.
Neither seems to give a shiny shit about the implications for the child. But it was never about the child, from day 1. Both thought a baby would mean they would become a kept woman, and if not, they'd have enough child support and benefits to live on anyway. I only know of this because both are close to member of my family, and I've had some interaction with them, and her directly. I think there are far more women like this than we think. It's awful.
My best friend, until she was 37, literally hated the idea of children. So did her partner. However she suddenly became broody. He still didn't want any. They split. She's now got a beautiful 2yr old with her new partner. That's what a decent woman does. Not stay with her original partner, lying that she hates the idea, having secretly come off the pill. Then the whole fake offence and "well you had sex with me, so you knew there was a chance." Yes you lied that there was a 1% chance, knowing it was a 30% chance. They wouldn't have been having sex at all if the women was telling the real truth about the zero contraception.