Can some explain capability for work to me please?

Hi 😊

I'm probably going to sound really stupid, I'm just confused as I don't have any experience with this.

I've been working full time at my current job for 2 and a half years, up until February when I was signed off by my GP due to high risk pregnancy complications. I'm still employed with my company. Unable to work from home as it's a physical job. Employers have been unable to make any adjustments to my role or hours.

UC asked me to fill out a Capability For Work assessment form due to this complication. I've sent it back all filled in and now I'm waiting to find out when I have an appointment to discuss it further.

I'm 26 weeks pregnant and I'll be going on maternity leave within the next 2 months.

Can their decision override my GPs? Is it necessary when this is only a temporary medical issue and will resolve once I've had the baby?