From the beginning Maxis had included a medical emergency call with the emergency phone calls but had kept it disabled and never made use of it. Even when they rewrote the phone calls for Pets EP they rewrote the medical emergency call without enabling it. This enables the call, first for pregnant sims that are in the last trimester, which is the Maxis default, second for sims with a potentially lethal disease.
Build your own working hospitals with nurses and doctors. Send your sims to the hospital to get cured or to have their babies.