In my large UK-based airline both Cabin Crew and Flight Crew are grounded as soon as they inform the company that they're pregnant.
Some Cabin Crew who live near to our headquarters are given office work but apparently there are too many pregnant crew to give them all work so most stay at home on basic pay during their pregnancies. They're not fired.
Our Flight Crew are given office jobs and basic pay. It seems to be a lottery as to which jobs/projects they're given but the company tries to keep it loosely related to Flight Ops. If they live too far away for a daily commute they're given a laptop and work from home.
Both Cabin Crew and Flight Crew in my company get 90% of their pay for 6 weeks from the day they start their maternity leave. Then it's onto the UK's statutory maternity pay (£117 per week) for up to a year, giving 8 weeks notice to the airline about when they want to return to work.