She has assisted at over 1,000 births and is currently teaching in the nurse-midwifery program at the University of Minnesota. Much of how people react to medications depends on how much of the drug is metabolized, where it is metabolized, the contents of the stomach, the time of day it is taken, etc.
Some women lose weight on birth control pills, some gain and, of course, some stay the same.
Approximately as many women lose weight as gain weight while taking oral contraceptives. In some women, however, weight gain is definitely caused by oral contraceptives. Rarely, pills can cause a gain of 10 to 20 pounds or more. This pattern of weight gain occurs in the month or so after initiating pills. Estrogen-induced weight gain increases subcutaneous fat, particularly in the hips, thighs and breasts, typically occurring after several months on pills.