To assess obstetric anesthesia in the United States, and to determine why more anesthesia personnel are not involved in this subspecialty, a questionnaire was sent to the heads of obstetric and anesthesia services in 1,200 hospitals. Both obstetric and anesthesia respondents agreed on several characteristics of obstetric anesthesia that inhibit more participation by anesthesia personnel. Among others, they identified that: the unpredictability of labor and delivery makes scheduling difficult; obstetricians tend to dictate type and timing of anesthesia; the risk of malpractice claims is increased for obstetric anesthesia; and, finally, larger obstetric services would make it more practical to provide anesthesia services. Regarding availability of personnel and procedures, obstetric units with less than 500 deliveries per year were considerably more under-staffed than the larger units in most areas studied. When general anesthesia was used for cesarean section in these units, it was provided by, or given under the direction of, an anesthesiologist only 44% of the time, whereas in the hospitals with more than 1,500 deliveries per year, an anesthesiologist was present 86% of the time. Likewise, in the small units, personnel classified as "others" were responsible for newborn resuscitation in 24% and 43% of instances after cesarean section and vaginal delivery, respectively. In the hospitals with more than 1,500 deliveries, comparable figures were 4% and 2%, respectively.