You should speak with your travel company or airline. Normally, you can’t fly if you’re more than 32 weeks pregnant at the time of your return flight, do not book your flight before checking the airline’s policy.
The fact that the disruption is being caused by an exceptional circumstance doesn’t affect the basic obligations of airlines and travel companies, However, it means that you aren’t entitled to additional compensation.
The UK government requires airlines to collect API for passengers before travel on routes to and from the UK. Some foreign governments also require API. Airlines will only provide each country’s authorities with the relevant information.