How about this...

Natalia overcome with the circumstances of her life, decided to leave Springfield to be alone and think. After some time of reflection, she decides that she and Olivia truly do belong together and that they can overcome anything. Natalia finds some who can take her back to Springfield. While driving back to be reunited with Olivia she is involved in a car crash and seriously injured. Her I.D./purse is not immediately recovered from the accident site so the hospital/doctors have no way of knowing who she is and cannot contact anyone about her accident. This is also why Olivia has not heard from or been contacted by Natalia. Tragically the baby Natalia was carrying does not survive the car accident. The police continuing their investigation of the accident finally recover Natalia