Abstract
Although only 1.3% of abortions in the United States are between 20 and 24 weeks’ gestation, these procedures are associated with elevated risks of morbidity and mortality. Adequate cervical preparation before dilation and evacuation (D&E) at 20–24 weeks’ gestation reduces procedural risk. For this gestational range, at least one day of cervical preparation with osmotic dilators is recommended before D&E. The use of overnight osmotic dilators alone is sufficient for most D&Es at 20–24 weeks’ gestation. Dilapan-S® dilators require a shorter time to achieve maximum dilation, may be more effective than laminaria and may increase the likelihood of success on the first D&E attempt. The use of adjunctive mifepristone administered one-day pre-operatively at the time of osmotic dilator placement, should be considered because evidence demonstrates that it makes D&E subjectively easier at 20–24 weeks without increasing side effects. While older studies suggest that two-days of serial osmotic dilators provide greater dilation than one day of dilators, adjunctive mifepristone may be comparable to a second day of dilators. Adjunctive misoprostol administered on the day of D&E does not appear to affect initial cervical dilation and procedure time and compared with mifepristone is associated with more side effects, such as pain and nausea. Using overnight mifepristone and same-day misoprostol without osmotic dilators at 20–24 weeks’ gestation lengthens D&E procedure time and appears to increase immediate complications, at least among less experienced providers. Some evidence shows the feasibility of same-day cervical preparation before D&E at 20–24 weeks using Dilapan-S® with adjunctive misoprostol or serial repeat dosing of misoprostol, but same-day preparation should be limited to providers with significant experience with these regimens. The Society of Family Planning recommends preoperative cervical preparation before D&E at 20–24 weeks’ gestation. Further studies are needed to clarify the best means of preparing the cervix in order to minimize abortion complications and improve outcomes in this gestational range