This is a summary of a recent systematic review (Bank et al., 2023) that examined whether there is sufficient evidence to support the commonly held belief that optimal neonatal outcomes are achieved when the decision-to-incision time for emergent cesarean birth is less than 30 minutes.

Background

Beginning with the second edition of Guidelines for Perinatal Care (American Academy of Pediatrics [AAP] & American College of Obstetricians and Gynecologists [ACOG], 1988), there was consensus that hospitals should have the capacity to initiate a cesarean birth within 30 minutes of the decision to do so. In 2017, acknowledging that there was insufficient evidence to support the standard, AAP and ACOG (2017) amended the recommendation to allow for consideration of maternal and fetal benefits and risks and local circumstances. Despite this change, the 30-minute decision-to-incision threshold has remained an accepted legal and quality standard.

Findings

Findings from the review emphasized that many neonatal outcomes are caused by factors occurring throughout the perinatal period rather than events during labor, and that neonatal outcomes may differ when accounting for reversible and irreversible causes of fetal compromise. Studies have typically not reported on the reversibility of the fetal stressor(s) or strategies implemented for intrauterine resuscitation. For irreversible events such as uterine rupture or cord prolapse, adverse neonatal outcomes may begin to occur at 10 to 15 minutes (Bank et al., 2023). Emergency cesarean birth has been associated with adverse maternal outcomes such as bladder and bowel injury; wound infection; and higher odds of blood transfusion, broad ligament hematoma, and uterine artery ligation. General anesthesia, which is often used for emergency cesarean birth, has been associated with postpartum hemorrhage and adverse maternal mental health outcomes. For both neonatal and maternal outcomes, the review found insufficient evidence to support a set decision-to-incision standard (Bank et al., 2023).

Recommendations

Instead of applying a 30-minute decision-to-incision threshold to all situations, Bank et al. (2023) recommend categorizing unplanned cesarean births into a 4-tier classification (Class I-IV) based on urgency and level of maternal and fetal risk. This approach was recently implemented in the United Kingdom (National Institute for Health and Care Excellence, 2021). Class I includes scenarios where there is an immediate threat to the mother's or fetus's life requiring prompt delivery. Examples are persistent fetal bradycardia, umbilical cord prolapse, complete placental abruption, and actual or impending maternal cardiac arrest. Birth should occur as quickly as possible while attending to maternal safety. Class II includes scenarios where there is concern for maternal or fetal well-being but where the timing of cesarean birth may be delayed. This allows for conservative management with intrauterine resuscitation, while assembling additional personnel, preparing for potential blood replacement products, and initiating regional anesthesia. Examples are a nonbradycardic category III fetal heart tracing, worsening preeclampsia remote from birth, or concerning maternal or fetal situations which are not immediately life threatening. Class III includes scenarios where there is no immediate maternal or fetal threat, but birth is recommended. For example, arrest of labor without maternal or fetal concern. Class IV includes a cesarean birth that can be planned based on the patient's and healthcare team's schedule. Examples include elective cesarean birth, malpresentation, stable placenta previa, or a patient with a prior cesarean who is not in labor.

Conclusion

Nurses and other perinatal leaders are urged to read the full review available at https://www.ajog.org/article/S0002-9378(22)00461-6/fulltext. Based on available evidence, the long-held "30 minute rule" needs to involve a more flexible clinical decision process for determining timing of cesarean birth when there are concerns about fetal and maternal well-being.

References