Does the blessing of Asher Yatzar (normally said upon using the bathroom) apply in other situations. For example in passing a kidney or gallstone? A woman who's water breaks or passes her mucus plug? Would it be said after childbirth if a woman moves her bowels during labor, which is very common? Are there any other situations where this blessing should be said?
The G'mara in B'rachos 60b says that the situation in which one says this blessing is upon leaving the bathroom. Although the text of the blessing mentions many natural/biological phenomena that God effects, the applicable context appears to be limited to that one. In fact, Dr. Beni Gezundheit (in Section ד Part 2 of this article) cites late sources that limit the situations warranting the blessing only to certain instances of "leaving the bathroom" - either those which provide some relief from discomfort or those which themselves are not a cause for discomfort.
It would appear that we do not apply this blessing outside of going to the bathroom. For instance the blessing is not recited after sneezing, vomiting or birthing a baby. The lack of obligation to say asher yatzar for those much more common occurrences would indicate that none should be necessary for rarer situations. Regarding a women who moved her bowels during labor, I believe that if someone has an accident, due to being inebriated or because of some medical condition, they do not recite the blessing as they are not cognizant of the benefit they received - similarly if one was about to be force-fed (chalilah) there would be no obligation to bless beforehand.
Clearly this is all my own thinking, please consult a Rabbi for practical advice
The halacha is brought in the Shulchan Aruch Orach Chaim Siman 4 that even if you do not go to the bathroom you must still say asher yatzar in the morning. The Bach explains that the reason (or one of the reasons [I did not see the Bach inside]) is because while sleeping one passes gas.