The Pros and Cons of Oral Contraceptives

Dr. Dharmakanta Kumbhakar

Although oral contraceptives have been in use for more than 30 years, and despite the innumerable analysis of their effects, experts continue to disagree about their safety and adverse effects. These drugs nearly always contain synthetic estradiol and variable amounts of a progestin (combined contraceptives), but a few preparations contain only progestins. Currently prescribed oral contraceptives contain smaller amounts of estrogens (<50 microgram per day) and are clearly associated with fewer side effects than their earlier formulation.

Apart from the family planning benefits of oral contraceptive use, the other beneficial effects are relief of dysmenorrhoea, premenstrual tension, endometriosis, acne, hirsutism, protection against benign breast disorder, including fibrocystic disease and fibroadenoma, ovarian cyst, iron deficiency anemia and lesser chance of ectopic pregnancy and pelvic inflammatory disease.

The minor unwanted effects of oral contraceptive use are nausea, vomiting, headache, migraine, depression, change of mood disorder, sleep disturbance, break through bleeding, diminished libido, leucorrhoea, breast tenderness, breast fullness, leg cramp, weight gain and hypomenorrhoea or amenorrhoea.

The issue of breast cancer risk is controversial. Despite the disagreements, the prevailing opinion is that there is a slight increase in breast cancer when combined oral contraceptives are used by women younger than 45 years, particularly nulliparous women younger than 25 years. For women older than 45 years, the risk, if any, is negligible.

Oral contraceptives carry some increased risk of cervical cancer, which is co-related with duration of use. More recent studies suggest that the increased risk may be more strongly co-related with life style than with the drug. Oral contraceptive probably exert a protective effect against endometrial cancer. Oral contraceptives protect against ovarian cancer: the longer they are used, the greater the protection and this protection persist sometime after use stops.

The oral contraceptives used in the past (>50 micro gram estrogen) were clearly associated with an increased risk of venous thrombosis and pulmonary thromboembolism because of increased hepatic synthesis of coagulation factors and reduced levels of antithrombin III. Data with the newer (second-generation) formulations (<50 micro gram estrogens) suggest that the overall risk is much less, especially in women younger than 35 years who don’t smoke and don’t have other predisposing influences such as diabetes. More recently, third-generation oral contraceptives, which combine low dose estrogens with synthetic progestins, affect LDL and HDL levels to a lesser extent than natural progestins do and hence the risk of acute myocardial infarction is reduced. However, unexpectedly, the third-generation oral contraceptives confer a higher risk of venous thrombosis than do second-generation oral contraceptives. Furthermore, there is an even greater risk of venous thrombosis in users who are carriers of a mutation of factor V. The carrier rate of the factor V mutation is fairly high (2% to 15%) in whites.

Even the newer low-estrogen formulations of oral contraceptives cause a slight increase in blood pressure. The effect is more marked in older women with a family history of hypertension.

Estrogens and progestins have opposing effects on high-density lipoprotein (HDL) and low-density lipoprotein (LDL) levels. Estrogen tends to elevate the level of HDL and reduces the level of LDL. This lipid profile is protective against the development of atherosclerosis. Progestins, on the other hand, tend to lower HDL and elevate LDL which counters the estrogen effect. The overall effect on the levels of these lipoproteins seems to depend on the preparations used, particularly the dose of progestin in the formulation. There is considerable uncertainty regarding the risk of atherosclerosis and myocardial infarction in users of oral contraceptives. The risk depends on the estrogen content of the formulation, the age of the women and the presence or absence of other risk factors for atherosclerosis, especially smoking. Recent evidence states that non-smoking, healthy women younger than 45 years who use the newer low-estrogen formulation do not incur an increased risk of ischemic heart disease. Conversely, young women smokers who use the pills are ten times more likely to suffer myocardial infarction than users who do not smoke.

There is a well-defined association between the use of oral contraceptives and the rare benign tumor hepatic adenoma, especially in older women who have used oral contraceptives for prolonged periods.

Obviously, the pros and cons of oral contraceptives use must be viewed in the context of their wide applicability and acceptance as a form of contraception that protects against unwanted pregnancies.