Fever on day 4 after chemo?

Kkmay

Hi

My mom had her first AC last Sunday. She had minimum side effects expect for a mild fever (38 °C) on day 4 post treatment. We went to the hospital they have checked her white blood cells, and they are within average (higher than the typical cancer patient). The docter told us not to take any antibiotics unless the fever persists for more than two days. My question: could this be just a side effect of chemo? Or Could itbe a sign of infection? Any ideas?