Teamwork and communication gaps are consistently cited as contributors to adverse outcomes in obstetrics. The Critical Care in Obstetrics Course provides an innovative experience by combining brief interactive didactics with the opportunity to practice and implement the knowledge gained with hands-on simulation. Most participants have never worked together, which creates a unique environment to evaluate the importance of teamwork and communication. This study aimed to evaluate the association between teamwork and medical management in high-fidelity critical care simulations. The participants were separated into multidisciplinary teams and taken through simulations, including placental abruption, hypertensive emergency, eclampsia, sepsis, cardiac arrest, venous thromboembolism, diabetic ketoacidosis, and thyroid storm. Facilitators completed a validated checklist assessment for each group's performance in medical care and teamwork. Each element was rated on a scale from 1 to 5, with 1 being unacceptable and 5 being perfect. We evaluated 5 communication measures, including the use of closed-loop communication and orientation of new team members. A Spearman correlation was used to evaluate the relationship between total medical management and total teamwork scores and specific measures of team communication. Receiver operating characteristic curves were created for total teamwork score as a predictor of good or perfect medical management. A total of 354 multidisciplinary teams participated in 1564 high-fidelity simulations. There was a significant correlation between medical management and teamwork and communication scores for all scenarios. The strongest correlation was for the total teamwork score for all simulations (ρ=0.84). Teamwork scores were highly predictive of medical management scores with an area under the curve of at least 0.88 for all simulations, although this was not significant for diabetic ketoacidosis. The quality of teamwork and communication correlated with the quality of clinical performance in newly formed multidisciplinary teams. This demonstrates the importance of teamwork training, with a focus on key communication tools and strategies, among medical providers to optimize the management of complex and emergent obstetrical conditions.