Oral contraceptives: a reassessment.Obstet Gynecol Surv. 1989 Sep; 44(9):662-8.OG
Cardiovascular risks attributable to oral contraceptive use may now be subdivided into those that appear to be secondary to the estrogen component, i.e., venous thrombosis, pulmonary embolism, and those linked to the progestin component, i.e., small vessel disease including myocardial infarction and cerebrovascular accident. It appears that venous risk is attributable to subtle changes in clotting factors, while arterial risk may be secondary to changes in glucose and lipid metabolism. In order to determine which women are at greatest risk from oral contraceptive use, Spellacy et al. has developed a risk scoring form that aids in the screening process. After excluding women with an absolute contraindication to pill use, women at greatest risk for cardiovascular disease related to oral contraceptive use are those with a family history of hyperlipidemia, gestational or overt diabetics, hypertensives, and smokers over the age of 35. The gradual reduction by manufacturers of the steroid content of oral contraceptives appears to have lessened the incidence of adverse effects. Our current knowledge of risk factors permits the clinician to reduce exposure to oral contraceptive-related mortality by as much as 86 per cent. As we continue to search for ways to reduce risk among oral contraceptive users, it is important to note that more than 25 per cent of women are still taking formulations containing 50 micrograms of estrogen. It becomes the responsibility of the practicing physician to "step-down" these patients to lower-dose preparations such as the multiphasics. Such preparations also represent optimal therapy for first-time pill users.