Her operation date was fixed for Tuesday, the same day she began to have breathing difficulties.
She told doctors that in case she died during childbirth, she and her family were ready to donate her corneas to help visually-impaired people regain their sight.
Her story has received wide media coverage and moved thousands of people online. Many people have donated cash, baby clothes and other supplies for the mother and child.
"We have raised more than 10,000 yuan for Lyu and her baby and will visit them at the hospital after she recovers from the operation," said Ma Bin, administrator of an online group for ALS patients.
There are currently about 200,000 ALS patients in China. Since treatment is expensive and not covered by most social welfare programs, many are forced to forego care.
ALS strikes one to three people in every 100,000. Patients progressively lose muscle strength, eventually becoming paralyzed and unable to speak, move, swallow or breathe. British scientist Stephen Hawking is one of the most well-known ALS patients.