Maternal collapse: Challenging the four-minute rule

• Half of maternal/fetal pairs who are delivered by Cesarean birth within 25 min survive without injury.
• The injury free survival rate for both has a roughly linear decrease as the time interval from arrest to birth increases.
• Very few babies could be delivered within 1 min of the Cesarean section incision.This information suggests that the current cardio-pulmonary resuscitation guideline in pregnancy, known as the four-minute rule, needs to be changed. Injury free survival for both mother and baby decreases steadily from the moment of cardiac arrest until cesarean birth. Furthermore, in actual practice, the baby usually cannot be delivered within 1 min of the start of surgery. Once a decision for delivery has been made, Cesarean birth should be initiated promptly without waiting for 4 min. In practice, the recommendation to proceed to cesarean birth without delay is also likely to result in less confusion than the current “Four-Minute rule.”

IntroductionThe current approach to, cardiopulmonary resuscitation of pregnant women in the third trimester has been to adhere to the “four-minute rule”: If pulses have not returned within 4 min of the start of resuscitation, perform a cesarean birth so that birth occurs in the next minute. This investigation sought to re-examine the evidence for the four-minute rule.MethodsA literature review focused on perimortem cesarean birth was performed using the same key words that were used in formulating the “four-minute rule.” Maternal and neonatal injury free survival rates as a function of arrest to birth intervals were determined, as well as actual incision to birth intervals.ResultsBoth maternal and neonatal injury free survival rates diminished steadily as the time interval from maternal arrest to birth increased. There was no evidence for any specific survival threshold at 4 min. Skin incision to birth intervals of 1 min occurred in only 10% of women.ConclusionOnce a decision to deliver is made, care providers should proceed directly to Cesarean birth during maternal cardiac arrest in the third trimester rather than waiting for 4 min for restoration of the maternal pulse. Birth within 1 min from the start of the incision is uncommon in these circumstances.

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