Timing of elective cesarean section
Measurement of cervical length
There is a contradiction in the timing of elective cesarean sections which are traditionally performed at 38 weeks.
Delay beyond 38 weeks will result in many women going into spontaneous labor and consequently an elective procedure will be converted into an emergency one with increased maternal mortality and morbidity.
The risk of respiratory morbidity in the neonate is halved with each completed week of gestation between 37 and 41 weeks.
Measurement of cervical length at 37 weeks is useful in predicting spontaneous onset of labor and delivery at term. This information can be utilized in individualizing the gestation for elective cesarean section:
In women with cervical length of less than 20 mm there is a 95% chance of spontaneous onset of labor before 40 weeks. In such patients elective cesarean section is best carried out at 37–38 weeks to avoid the increased risk of maternal mortality and morbidity from emergency as compared with elective surgery.
In women with cervical length of more than 30 mm there is a 95% chance that spontaneous onset of labor will not occur before 40 weeks. In such patients elective cesarean section could be delayed until 40 weeks to reduce neonatal respiratory morbidity.
Cervical length at 37 weeks