To determine the characteristics of maternal varicella at our institution, we reviewed all cases of primary varicella in pregnancy. Using a perinatal database that summarizes all obstetric admissions, we reviewed the medical records of women with varicella infections during pregnancy. Over a 5 1/2-year period, 31 pregnancies were affected by varicella infection among 11,753 deliveries. The mean age of those patients was 19.6 years, significantly different from our overall population of 25.3 years (P < .05). The racial composition of 35% Hispanic, 35% white, and 29% African American was different from that of our general population of 55% white, 38% African American, and 6% Hispanic (P = .023). The mean gestational age of the eruption of vesicles was 25 weeks. Of the 31 women, 7 had preterm labor within a week of their varicella, 3 delivered prematurely, and 3 infants had a birth weight of less than 2,700 grams. Respiratory symptoms developed in 6 women, and pneumonia developed in 4, 2 of whom required ventilatory support, 1 for 5 days, the other for 49 days. Eight women received acyclovir during gestation, and none suffered sequelae. In all, 6 infants had lesions and anomalies noted at birth, 5 possibly associated with varicella. Varicella infection is associated with a greater-than-expected level of both maternal and fetal morbidity. The fetal disease may occur due to maternal infection at any gestation and is most likely a spectrum of complications. The maternal disease appears to be worse in the latter half of pregnancy. Programs of prevention through vaccination must account for a possibly decreased level of immunity in different populations.