Maternity leave and long term sick

Hello,

I am currently 25 weeks pregnant with a high risk twin pregnancy. I am down to begin maternity leave just before 36 weeks. I have had to have a number of days off both in the first and second trimester for pregnancy related illness and back pain. None of these periods of absence required a sick note.

I am currently off work with sciatica pain and pain in my ribs, I'm finding it incredibly difficult to do basic things like get out of bed and stand in the kitchen etc. I think I will most likely need to be signed off from Monday.

I'm worried about the length of time I may need to take off and wondered whether anyone has any experience of this?

I am still quite far away from starting my maternity leave and due to financial reasons, I do not want to start early.

Can I be penalised or meet any of the trigger points for absence whilst off with pregnancy related illness?

Any advice or experiences would be greatly appreciated.

Thank you