Ethinyl estradiol and norgestrel are a combination of drugs used as hormonal contraceptive in women. Ethinyl estradiol is synthetic estrogen analogue and norgestrel is a synthetic progesterone analogue.
Mechanism of action
Ethinyl estradiol and norgestrel cause feed back inhibition of GNRH (Gonadotropin releasing hormone), FSH (follicle stimulating hormone) and LH (leutinizing hormone). Thus the mid cycle LH surge is prevented and ovulation does not occur. Progesterone makes the cervical mucus thick and impenetrable to sperms. The tubal and uterine motility is affected in such a way as to prevent fertilisation. Even if ovulation and fertilization occurs, the endometrium will be out of phase with the fertilization and implantation does not occur. The addition of progesterone ensures that the bleeding will occur after the cycle so that continuous endometrial proliferation and potential for endometrial carcinoma by estrogenic stimulation is prevented.