BACKGROUND: High neuraxial block is a rare but serious adverse event in obstetric anesthesia that can ultimately lead to respiratory insufficiency and cardiac arrest. Previous reports on its incidence are limited to populations in the United Kingdom and the United States. Little is known about the incidence and clinical features of high neuraxial block in the Netherlands, where the presence of anesthesiologists in the labor and delivery unit is comparatively lower. We aimed to assess the incidence and clinical features of high neuraxial block in obstetrics and to formulate ways to improve obstetric anesthesia on a national level. METHODS: This nationwide, prospective, population-based cohort study was designed to identify cases of high neuraxial block requiring ventilatory support (with supraglottic airway device or tracheal intubation) or cardiopulmonary resuscitation between November 2019 and May 2022. Cases were prospectively collected using the Netherlands Obstetric Surveillance System (NethOSS) in all hospitals with a maternity unit. Complete case file copies were obtained to determine risk factors and clinical course. RESULTS: During the study period, 5 cases of high neuraxial block requiring tracheal intubation were identified. The estimated incidence of high neuraxial block requiring tracheal intubation was 1 in 29,770 neuraxial procedures in labor (95% confidence interval, 1:12,758–1:91,659). Three of 5 identified cases occurred in the operating room after single-shot spinal anesthesia for Cesarean delivery after epidural analgesia in labor. One case developed in the labor ward due to an inadvertent intrathecal or subdural catheter placed for labor analgesia. The fifth case followed single-shot spinal anesthesia for elective Cesarean delivery. All 5 patients were successfully extubated in the operating room after Cesarean delivery, without the need for intensive care admission. There were no cardiac arrests and no neonatal deaths. CONCLUSIONS: High neuraxial block requiring tracheal intubation is a rare ...