 In some parts of the body, its action is estrogenic (e.g., bones), in other parts of the body, its action is antiestrogenic (e.g., uterus, breasts).It causes an asynchrony in the menstrual cycle between ovulation and the development of the uterine lining, although its exact mode of action is not well defined.In clinical trials, it caused ovulation to occur later than it normally would in some women, but did not affect ovulation in the majority of women, while causing the lining of the uterus to build more slowly.