We describe five cases of Q fever in pregnant women that were diagnosed during the last 3 years in the town of Martigues in Southern France. Analysis of our cases and the 18 other published cases shows that Q fever is a significant cause of morbidity and mortality in pregnancy. The disease may present as an acute or chronic infection and can be reactivated during subsequent pregnancies, as is seen with other mammals. In Martigues, Q fever is present in at least one per 540 pregnancies and constitutes the most significant public health problem related to intrauterine infections.