complications
n. countablen. extra problems that make a situation more difficult to deal with. In medicine, it means a new medical problem that happens while you are already sick or having surgery.
n. circumstances that complicate or confuse a situation, making it more difficult to resolve. In a medical context, it refers to secondary diseases or conditions that develop during the course of an existing illness or treatment.
The surgery was successful and there were no complications.
The project was supposed to be simple, but several technical complications delayed the launch by three months.
While the initial infection was mild, the patient developed respiratory complications that required a prolonged stay in the intensive care unit for specialized monitoring.
Almost always used in the plural form when referring to general difficulties or medical side effects.