The 36-year-old woman from the nearby Russian republic of Mordovia "was admitted to the clinic for an urgent operation to replace an artificial heart valve, which the patient had been living with for several years," Dr. Vladlen Bazylev told RIA Novosti.
Replacing a heart valve usually involves open-heart surgery, and is considered a high-risk procedure.
Surgeons were preparing to carry out the operation, when the woman went into labor, two and a half months before she was due. The doctors decided to carry out a cesarean section, before replacing the valve.
After more than six hours on the operating table, the woman's condition is satisfactory. Dr. Bazylev said the baby girl is being closely monitored, but is not in any danger.