This is a retrospective case-control study to calculate the incidence of varicella zoster (VZ) in pregnancy, to know why the incidence is high and to suggest a strategy to prevent the disease. Twenty-one pregnant women with VZ were compared to two control groups. The first control group ( n =30) had normal pregnancy and no VZ. The second control group ( n =27) had VZ and no pregnancy. Assir region has a total population of 150 000 (Abha area). The incidence of VZ in pregnancy in Asir region during the study period was 0·23%, which is high if compared to other studies. In comparison to controls, cases had a significant increase in fever episodes, hospital admission, viral pneumonia and hospital stay. P values were <0·0001, <0·0001, <0·05 and <0·01, respectively.Also, VZ in pregnancy negatively affected the perinatal outcome as evidenced by a significant increase in congenital malformation and neonatal admission to NICU ( P <0·0001 and <0·002, respectively). The high incidence of VZ during pregnancy can be explained by the social behaviour of the population under study. In a conservative society unmarried women rarely mix and contact with viral infections is minimal. After marriage and during pregnancy the social exposure of the non-immune to cases becomes more frequent. Also, contact with cases was greatly enhanced by the social mixing in modern facilities such as schools, shopping centres and health facilities. Recently an effective VZ vaccine has been introduced successfully. It will be prudent to include the vaccine in the expanded program of immunisation already adopted by our health authorities. This will be cost-effective and many cases can be averted.