gynecology and obstetrics
Oral Contraceptives
Introduction
Oral contraceptives (OCs) are steroid hormones that inhibit the release of gonadotropin-releasing hormone (GnRH) by the hypothalamus, thus inhibiting the release of the pituitary hormones that stimulate ovulation. OCs also affect the lining of the uterus, decreasing the likelihood of implantation of an embryo, and cause the cervical mucus to thicken, making it impervious to sperm. If used consistently and correctly, OCs are an effective form of contraception. OCs may be started at any age from menarche until menopause. OCs may be a combination of the hormoneestrogenand aprogestinor aprogestinalone. 