What goes on in the life of a student and is not related to school should not be the business of the school. It would be, therefore, unethical for Donna to call Melissa's parents and tell them that their daughter is pregnant. That information was told to Donna in confidence and does not have anything to do with the girl's performance at school. Conclusion

In short, it would appear that Donna should avoid telling Melissa's parents of the pregnancy and intended abortion, because it does not relate to school business and Melissa is old enough to get an abortion without parental consent in her state. While it is understandable...

She should keep them to herself and not attempt to impose them on Melissa, who should be allowed to make her own choice.
References

De La Torre, M.A. (2004). Doing Christian ethics from the margins. NY: Orbis Books.

Fagothey, a. (2000). Right and reason. Rockford, IL: Tan Books & Publishers.

Sarat, a. et al. (eds.). 2005. The limits of law. Stanford: Stanford University Press.

Schools barred from telling parents of abortion (2004). Law of the Land. WND. Retrieved from http://www.wnd.com/2004/12/27841/

Stone, C. (2004). Legal and ethical dilemmas in abortion counseling. American School Counselor Association. Retrieved from http://www.schoolcounselor.org/magazine/blogs/january-february-2004/legal-and-ethical-dilemmas-in-abortion-counseling