Benefits and risks of oral contraceptive use
Williams, R.S.
Postgraduate Medicine 92(7): 155-7 161-2 168-71
1992
ISSN/ISBN: 0032-5481 PMID: 1437913 DOI: 10.1080/00325481.1992.11701539Document Number: 324127
The effectiveness of monophasic and multiphasic oral contraceptives (OCs) depends on their ability to suppress ovulation, change endometrial growth and ovum receptivity, and reduce cervical mucus receptivity to sperm. They are all more than 99% effective, but, depending on the type and dose of hormone components, they have different side effects. The estrogen component (ethinyl estradiol) of most new OCs is between 30 and 35 mcg, which reduces the risk of estrogen side effects, especially thromboembolism and hypertension. The Food and Drug Administration does not recommend use of an OC with an estrogen component for lactating mothers, while the American College of Obstetrics and Gynecology and the American Academy of Pediatrics believe it is fine. Estrogen may protect against coronary artery disease, yet the estrogen component of today's OCs is so low that the progestin component may cancels this beneficial effect. It also prevents breakthrough bleeding. The most frequently used progestins in OCs are norethindrone and norgestrel. They prevent ovum implantation, sperm penetration through the cervical mucus, and ovulation. Progestins, especially norgestrel, increase the risk of coronary artery disease. Other side effects include acne and weight gain. Progestin benefits are reduced menstrual blood loss, pain during menstruation, premenstrual tension, and endometrial cancer risk. The ideal estrogen-progestin balance depends on the individual, but the estrogen component should be between 30 and 35 mcg, and the progestin component should be the lowest possible dose to reduce metabolic side effects. If an OC user with a well stabilized cycle who takes another recently prescribed drug experiences unexpected breakthrough bleeding or spotting, this change may indicate a drug interaction. Absolute and/or possible contraindications of OC use are smoking after age 35, history of breast or endometrial cancer, liver disease or impaired liver function, cardiovascular risk factors, and diabetes mellitus.