Susan Torres was found to have a cancerous growth in her head that caused pressure on her brain and loss of consciousness on May 7.
Her husband Jason Torres decided to continue life support to save the 5-month-old fetus.
However, there is a possible complication all are watching, The Washington Post reported Friday. The kind of cancer Susan Torres has can be transferred to the fetus through the placenta, her husband said.
"I don't think it would be unethical to stop (life support) now. But given the chance to save the life of the child, we've got to give it a try," he said.
The Post said there were 11 known similar cases since the 1970s and most were successful in prolonging the pregnancies until the fetus could live outside the womb.