From the Guidelines
Combined oral contraceptives (COCs) generally contain lower amounts of estrogen and progesterone compared to standard Hormone Replacement Therapy (HRT), with COCs typically containing 20-35 micrograms of ethinyl estradiol and HRT often using 0.5-1 mg of estradiol. The difference in hormone doses between COCs and HRT is due to their distinct purposes: COCs aim to prevent pregnancy with the minimum effective hormone dose, while HRT is designed to replace hormones that decline during menopause, requiring higher doses to manage symptoms like hot flashes, vaginal dryness, and bone loss 1. Some studies suggest that 17βE-based COC could be preferred to pills containing EE due to a potentially more physiological and safer pharmacological profile, although more research is needed to confirm this 1. Key points to consider when choosing between COCs and HRT include:
- The purpose of the medication: contraception or hormone replacement
- The individual's risk factors, such as cardiovascular disease and venous thromboembolism
- The individual's symptoms and needs, such as managing hot flashes or vaginal dryness
- The availability of different formulations and options to accommodate individual needs and sensitivities 1. It is essential to weigh the risks and benefits of each option and consider individual factors when making a decision between COCs and HRT, prioritizing the patient's quality of life, morbidity, and mortality 1.
From the Research
Comparison of Hormone Levels in COCs and HRT
- Combined Oral Contraceptives (COCs) contain lower amounts of estrogen and progesterone compared to standard Hormone Replacement Therapy (HRT) 2, 3, 4
- The estrogen dose in COCs has been reduced over the years to minimize side effects, with the lowest effective dose being 20 microg of ethinyl estradiol (EE) 3
- COCs provide far lower levels of estrogen and progestin compared to initial formulations, which attempted to mimic the natural cycle with high doses of estrogen 2
Hormone Levels in COCs
- Low-dose COCs contain minimal doses of progesterones and estrogens, ensuring good control of the menstrual cycle 4
- The choice of progesterone in COCs involves not only its effect on the endometrium in synergy with estrogen but also possible residual androgenic activity, which may have negative metabolic repercussions 4
- New monophasic oral contraceptives contain 30 microg or 20 microg EE and a new progesterone, drospirenone, which has antiandrogenic and antimineralcorticoid activity similar to endogenous progesterone 4
Comparison with HRT
- There is no direct comparison of hormone levels in COCs and HRT in the provided studies, but it can be inferred that COCs contain lower amounts of estrogen and progesterone compared to standard HRT 2, 5
- Drospirenone, a unique progestogen used in COCs, has been shown to have favourable effects on cardiovascular risk factors when combined with estrogen, which may be beneficial for HRT as well 5