When should perimortem cesarean section be performed if return of spontaneous circulation is not achieved?

The timing of a perimortem cesarean section is critical, especially in cases of maternal cardiac arrest where fetal resuscitative efforts are also needed. Research indicates that if spontaneous circulation does not return within four minutes after the mother’s cardiac arrest, the chances of fetal survival diminish significantly. Performing a cesarean section by this timeframe (around four minutes) can maximize the likelihood of fetal viability and decrease the risks associated with prolonged maternal cardiac arrest.

This urgency arises from the notion that the fetus, particularly after 20 weeks of gestation, is at risk for hypoxia due to a lack of maternal circulation. After four minutes, not only does fetal survival decrease, but prolonged hypoxia can also lead to serious neurological impairment or death for the fetus. Therefore, when resuscitative efforts on the mother fail within this critical window, the surgical intervention can help alleviate pressure on the placenta and umbilical cord, potentially improving outcomes for the fetus.

In contexts where timing exceeds four minutes, the benefits of performing a cesarean section significantly decrease, which is why the other suggested times are less favorable in this acute emergency scenario.