24-hour Mifepristone and Buccal Versus Mifepristone and Vaginal Misoprostol for Cervical Preparation for D&E

Standard of care for cervical preparation prior to second trimester surgical abortion has traditionally been a pelvic exam with speculum, a paracervical block with lidocaine, and placement of a number of osmotic dilators through the cervical canal. Dilators obtain maximal expansion within 4-6 hours and patients experience cramping with this process. This cervical preparation allows for a faster procedure for the patient (limiting time for anesthesia) and an easier procedure for the provider (decreasing necessity for further dilation, decreasing risk of cervical laceration, and decreasing blood loss). Following cervical preparation, trained providers use instruments to remove the pregnancy per standard of care. Several studies have examined the use of medication (mifepristone and/or misoprostol) to dilate the cervix as an alternative to osmotic dilators . Patients prefer medication to dilators as medication is associated with less discomfort. Medications alone can achieve adequate cervical preparation but the optimal timing and routes of these medications has not been sufficiently evaluated.

The addition of mifepristone, a progesterone antagonist, to a misoprostol regimen has been shown to significantly decrease the medication-to-abortion interval in second-trimester induction terminations. Vaginal administration has demonstrated improved dilation as compared to buccal administration but it is known that patients prefer buccal administration. A comparison of mifepristone and vaginal versus mifepristone and buccal misoprostol has not been studied prior to second-trimester surgical abortion.

A review of cervical preparation for second-trimester D\&E did not recommend mifepristone and misoprostol for cervical priming due to high rates of pre-procedural expulsions. However, the primary basis for this conclusion is a trial in which the 48-hour interval between the medications accounts for the high out-of-facility expulsion risk. A retrospective cohort of over 200 women between 14 and 19 6/7 weeks gestation showed no difference in difficulty of cervical dilation for patients receiving mifepristone 24-48 hours misoprostol as compared to osmotic dilators prior to surgical abortion. Two out of facility expulsions occurred in the mifepristone-misoprostol arms but the timing of medication to expulsion interval is not reported.

More recent studies have limited the timing of mifepristone to 24 hours or less prior to procedure. Mifepristone only has been shown to provide adequate cervical dilation as compared to osmotic dilators to 16 weeks gestation with noninferiority design to detect a 3-minute difference in procedure time. A 24-hour interval between 200mg mifepristone and 400mcg buccal misoprostol has been shown as non-inferior to osmotic dilators for total procedure time for 15-18 week surgical abortions. Mifepristone and one-set of osmotic dilators was found to be non-inferior for total procedure time as compared to two sets of osmotic dilators for surgical abortion 19-23 6/7 weeks gestation.

The addition of mifepristone has benefit as a cervical priming agent as an adjunct or alternative to osmotic dilators for surgical abortion, but it is not known whether the addition of vaginal versus buccal misoprostol changes cervical dilation and thus procedure time outcomes.