Determining Women's Preferences for Medical Abortion Using Willingness to Pay

The FDA-approved regimen for medical abortion specifies treatment with oral mifepristone followed 48 hours later by oral misoprostol. Women's experiences with this regimen were assessed in the early medical abortion trials that preceded FDA approval. The majority of women who used this regimen rated their experience as satisfactory or very satisfactory after the abortion was completed (Newhall 2000). A weakness of these data is that they were collected from women who likely had an a priori preference for medical abortion as demonstrated by their participation in experimental studies of this method. Other factors affecting women's preferences had little to do with medical abortion per se such as the ability to avoid the involvement of their insurance company by participating in a study or that the method was offered free of charge (Clark S, et al. 2000).

Since the time that these studies were performed, multiple investigations have evaluated alternative regimens of using mifepristone and misoprostol for medical abortion (Creinin MD, 2000). Improving efficacy, reducing side effects, and increasing the flexibility in the timing and route of medication administration have driven the development of these alternative regimens (Newhall EP and Winikoff B, 2000).

As with earlier studies, most trials of new regimens have assessed acceptability or satisfaction post-treatment. In general, overall satisfaction has been reported as high regardless of regimen (Ho PC, 2006). However, when asked about specific aspects of the medical abortion treatment, women's preferences appear to be more nuanced. Route of misoprostol administration is one example. Shannon, et al. (2006) compared mifepristone with oral or vaginal misoprostol and found an overall acceptability of 91%, regardless of route of administration. However, when specifically asked about preference for route, the odds of preferring oral administration greatly exceeded the odds of preferring vaginal (OR = 13.7, 95% CI 6.5-28.7). A preference for oral administration was also demonstrated in a comparative trial by Schaff, et al. (2001), however this preference was driven by the greater amount of pain experienced by the vaginal group.

Further insight into the complexity of acceptability and satisfaction with specific regimens was provided by a pilot study that I performed of mifepristone and buccal misoprostol (4 tablets of misoprostol dissolved between the cheek and gum for 30 minutes). Detailed information regarding acceptability, likes, and dislikes was collected pre- and post-treatment. As with other studies, 91% of women surveyed would choose medical abortion again. However, only 42% found the experience to be a positive one. When asked specifically about the buccal route of administration, 72% disliked some aspect of using misoprostol in this way. Of note, pre-treatment, just under half of the women would have preferred oral administration and 13% buccal. Post-treatment, women were asked which route they would prefer assuming equal efficacy. The majority (70%) listed oral whereas the preference for buccal dropped to 9%. Most women cited dissatisfaction with the experience of using misoprostol buccally either because it was inconvenient, tasted bad, or had a chalky aftertaste.

Questions about preferences usually include an assumption that all factors other than the specific attribute being examined are equal, which may or may not be the case. Careful examination of specific regimens presented as part of comprehensive scenarios joined with use of targeted questions may provide more insight into our lack of understanding of preferences. It is still unclear, for example, what decrement in efficacy, and subsequent need for a surgical procedure, in combination with what degree of expected side effect and expected amount of pain, and which route and timing of administration, women would find acceptable and thus would determine their preferences if all of the options were available to them.