A 33-year-old pregnant woman developed skin rash at the 40 weeks' gestation. She was diagnosed as primary varicella zoster infection. Upon hospitalization, she was administered acyclovir and also a tocolytic agent (ritodorine hydrochloride) to postpone labor. The patient delivered a female baby 7 days after she developed skin lesions. Serological tests conducted after delivery showed that the mother was positive for IgG and IgM against varicella zoster. The baby was observed in a neonatal intensive care unit and found to be free of varicella zoster symptoms.