Vaginal prostaglandins for labor induction

To begin with, a vaginal examination will be performed. This is to assess the state of the cervix and to determine whether the prostaglandins will be required and at what dosage. This will be followed by administration of the gel or pessary. This is followed by fetal monitoring for anything up to one hour, longer if necessary.

The fetal monitoring is essential because sometimes the uterus responds abnormally to the stimulus of the prostaglandins and causes fetal distress. Monitoring is therefore an essential precaution. Fetal distress is, however, a rare complication.

Most women will need one or two administrations, given four to six hours apart. In a few instances, more administrations of the gel or pessary may be required because of poor cervical response to the prostaglandins.

Rarely, no response occurs and the cervix remains obstinately unchanged. That will be a failed induction.

After achieving a favorable cervix...

After the prostaglandin course has achieved its aim, that is getting the cervix soft, thin and stretchy; the next step will be to perform an amniotomy or ‘breaking the waters’.

Once the waters are broken, uterine contractions are expected to follow. Some practitioners will start the oxytocin (Pitocin) infusion straight away after breaking the waters, while others advocate giving some time (one or two hours) to allow the uterus to start contracting spontaneously before considering the infusion.

Sometimes the waters will break following administration of the prostaglandins. Following instillation of the pessary or gel, changes take place to the cervix. As a direct result of this, probably combined with low-grade uterine activity, rupture of membranes may occur.

Labor following administration of prostaglandins

Sometimes, after the gel or pessary has been placed in the vagina, ostensibly to prime the cervix; labor ensues. This is because the prostaglandins do have effect on the uterine muscles as well. This means labor is established and will be managed like any other labor.

Lack of cervical response to prostaglandins

Failure of the cervix to respond to the prostaglandins presents a difficult situation. The attending obstetrician has to weigh up the options. One will be to try and go ahead with amniotomy (rupturing the membranes) and an oxytocin infusion. Such a strategy has a high chance of failure, especially if the cervix is in a very unfavorable state. It simply won't open.

The second option is to postpone the procedure for a few days and try again later. This is only possible where there is no concern for the baby's well-being by the continued stay in the womb.

The third option is to abandon the failed induction and deliver by cesarean section.

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