Hormonal contraception: main types

Hormonal contraception is a group of methods for preventing pregnancy based on the use of synthetic analogues of the female sex hormones estrogens and progestogens. These substances act on the same hormonal pathways as a woman's own hormones, but in controlled doses and according to a predetermined schedule, resulting in a stable contraceptive effect. Hormonal contraception includes pills, patches, vaginal rings, injections, subcutaneous implants, and hormonal intrauterine systems (IUSs). [1]

Current clinical guidelines consider hormonal contraception to be one of the primary and best-studied methods of regulating fertility. World Health Organization guidelines and national protocols emphasize that most women, in the absence of serious contraindications, can safely use one of the hormonal methods, and the choice depends on age, health, habits, and pregnancy plans. [2]

It's important to understand that hormonal methods vary in composition, route of administration, and duration of action. Combination methods contain both estrogen and progestin, while progestin-only methods contain only progestin. There are daily methods, which require regular use, and long-acting methods, which last for months or years after a single treatment. This creates a wide range of options for individual selection. [3]

In addition to preventing pregnancy, hormonal contraception often offers additional therapeutic benefits. It can reduce heavy and painful periods, improve acne, help with endometriosis and polycystic ovary syndrome, and reduce the risk of certain reproductive system cancers. For many patients, these benefits are just as important as contraception. [4]

At the same time, hormonal medications are not suitable for everyone. Certain conditions, such as severe thrombosis, certain tumors, and severe liver disease, make the use of certain hormonal methods unsafe. Medical acceptability criteria are used to assess suitability, clearly outlining which methods are acceptable for a given condition. Therefore, the choice should always be based on a consultation with a doctor, not solely on reviews or advertising. [5]

Table 1. Main groups of hormonal methods of contraception

Method group	Examples	Features of application
Combined hormonal methods	Tablets, transdermal patch, vaginal ring	Contains estrogen and progestogen
Short-acting, purely progestogen-only methods	Progestogen-only pills, progestogen injections	They do not contain estrogen and require regular intake or injections.
Long-acting methods with hormones	Subcutaneous implant, levonorgestrel intrauterine system	They work from several months to several years
Hormonal emergency contraception	Tablets for use after unprotected contact	Single dose within a limited time interval

[6]

The main types of hormonal contraception

Combined hormonal contraception includes medications that contain both estrogen and progestogen. This group includes combined oral pills, transdermal patches, and vaginal rings. All of these options share a common principle: consistently low doses of hormones that suppress ovulation and alter the lining of the uterus and cervix. Differences primarily relate to the route of delivery and convenience for the individual woman. [7]

Progestogen-only methods include progestogen-only pills, progestogen injections, and subcutaneous implants. These methods lack estrogen, making them particularly valuable for women with contraindications to estrogen use, such as those with migraines with neurological symptoms, a high risk of thrombosis, or during breastfeeding. The side effect profile is somewhat modified: irregular bleeding is more common, but the effect on blood clotting is reduced. [8]

Long-acting methods include subcutaneous progestogen implants and levonorgestrel-releasing intrauterine systems (IUSs). The implant is inserted under the skin of the arm and can provide protection for several years, while the IUS is placed in the uterine cavity and is also long-acting. These methods require no daily effort, are virtually free of user error, and are among the most effective methods of contraception. [9]

Hormonal emergency contraception is considered separately. These are pills containing levonorgestrel or ulipristal, taken for a limited period after unprotected intercourse to reduce the risk of pregnancy. This is not a method for regular use, but rather a backup option in case of emergency situations, such as a broken condom or missed pills. [10]

Finally, there are combined injectable regimens, which are used less frequently, and hormonal methods used for therapeutic purposes in gynecological conditions, where contraception serves both as a preventative measure and as part of therapy. Essentially, these are the same medications, but their prescription may initially be based on the treatment objective, not just the desire to avoid pregnancy. [11]

Table 2. Examples of hormonal methods by type and duration of action

Type of hormonal method	Examples	Estimated duration of action
Combination tablets	Various low-dose and micro-dose regimens	Daily intake is required
Combination patch	Weekly shift	About 1 week per patch
Combination vaginal ring	Ring with a cycle of about 3 weeks	One cycle per ring
Progestogen-only pills	Progestogen-only pills	Daily intake without breaks
Progestogen injections	Depot medroxyprogesterone acetate, norethisterone enanthate	From several weeks to 3 months
Implant and intrauterine system	Subdermal implant, levonorgestrel system	From 3 to 5 years depending on the model

[12]

How does hormonal contraception work?

The general principle of most hormonal methods is to suppress ovulation. A constant background of estrogen and progestogen, or progestogen alone, alters the functioning of the hypothalamus and pituitary gland, which stop producing the periodic peaks of hormones that trigger ovulation. As a result, the dominant follicle in the ovary does not mature, and the egg is not released into the fallopian tube, making fertilization extremely unlikely. [13]

The second important mechanism is a change in the properties of cervical mucus. Under the influence of progestogen, the mucus in the cervical canal becomes thicker and more viscous, significantly reducing its permeability for sperm. Even if some sperm do pass through, their number and speed will be significantly lower than under natural conditions, further reducing the likelihood of the sperm encountering a viable egg. [14]

Hormonal medications also alter the condition of the endometrium, the inner lining of the uterus. The endometrium becomes thinner and less prepared to receive and implant a fertilized egg. Even if an embryo is formed, the likelihood of its normal implantation in this lining is much lower. This mechanism is particularly pronounced in levonorgestrel-releasing intrauterine systems (IUDs) and, to some extent, in progestogen-only methods. [15]

Long-acting methods, such as implants and intrauterine systems, create a stable level of progestogen directly at the site of action or in the blood. This maintains constant suppression of ovulation or a pronounced effect on the endometrium and cervical mucus without daily dose fluctuations. This stability explains their very high efficacy and low dependence on human factors. [16]

After discontinuing hormonal medications, most of the mechanisms gradually disappear. Hormonal levels return to baseline, the pituitary gland and ovaries resume normal cyclic function, and the endometrium and cervical mucus regain their natural properties. The speed of recovery depends on the method: after pills, it takes weeks, after injections, it can take more than months, and after removal of the implant or system, the effect usually wears off fairly quickly. [17]

Table 3. Key mechanisms of action of hormonal contraception

Mechanism	What methods are particularly used?	Contribution to protection against pregnancy
Ovulation suppression	Combined methods, some gestagen	Excludes the presence of a mature egg
Changes in cervical mucus	All progestogen-only methods	Difficulty in the passage of sperm
Endometrial modification	Levonorgestrel intrauterine system, progestogen-only methods	Decreased probability of embryo implantation
Effect on tubal motility	Combined methods	Further reduction in the likelihood of egg and sperm meeting

[18]

Effectiveness of hormonal contraception

The effectiveness of any method is assessed using the Pearl Index—the number of pregnancies per 100 women over one year of use. For combined and progestogen-only hormonal contraception, with ideal use, the Pearl Index is typically less than 1, meaning pregnancy occurs in fewer than 1 woman in 100 per year. These figures are comparable to those of intrauterine systems and implants, which are considered the benchmark for reliability. [19]

With typical use, when missed pills, late patch or ring changes, and late injections are taken into account, the Pearl Index increases. For oral pills, it is about 7 pregnancies per 100 women per year, for injections it is about 4, while for implants and intrauterine systems it remains less than 1, even under typical conditions, because these methods are largely independent of the woman's actions. [20]

Among hormonal methods, the pill is the most sensitive to missed doses. Even several missed doses in a row, especially at the beginning of a pack or after a hormone-free interval, can significantly increase the risk of ovulation. In response, current recommendations suggest regimens with shortened or no breaks and detailed algorithms for dealing with missed doses to minimize loss of effectiveness. [21]

Injectables, implants, and intrauterine devices (IUDs) are considered long-acting methods that rely little on daily discipline. The main risk of decreased effectiveness is associated with delaying the next injection beyond the recommended interval or with a delay in replacing the device. Therefore, recommendations emphasize the importance of strict monitoring of the next procedure date, but if the timeframe is met, effectiveness is extremely high. [22]

It's important to remember that no hormonal method, including the most effective ones, protects against sexually transmitted infections. Protection against the human immunodeficiency virus and other infections is achieved only by using condoms or abstaining completely from sexual intercourse. Therefore, if you have multiple partners or are unsure of their status, your doctor usually recommends combining a hormonal method with a barrier method. [23]

Table 4. Estimated effectiveness of various contraceptive methods

Method	Ideal use (pregnancies per 100 women per year)	Typical use (pregnancies per 100 women per year)
implant	Less than 1	Less than 1
Intrauterine hormonal system	Less than 1	Less than 1
Progestogen injections	Less than 1	About 4
Combination tablets	Less than 1	About 7
Progestogen-only pills	Less than 1	About 7
Condom	About 2	About 13

[24]

Benefits and additional effects of hormonal methods

The main advantage of hormonal contraception is its high reversible effectiveness when used correctly. Women gain the ability to plan their pregnancies and control the interval between births, which has a positive impact on the health of both mother and child. Access to reliable contraception reduces the number of unwanted pregnancies and associated complications, including unsafe abortions. [25]

The second major benefit relates to menstrual cycle control. Combination pills make menstrual bleeding more predictable, less heavy, and less painful. This reduces the risk of iron deficiency anemia, improves quality of life, and facilitates daily activities, school, and work. Levonorgestrel methods in the womb are particularly effective for very heavy periods. [26]

Hormonal contraception often improves the condition of the skin and hair. Some progestogens have an antiandrogenic effect, reduce sebaceous gland activity, and help with acne and seborrhea. These properties are used in the treatment of acne in adolescents and young women when contraception is also needed. Skin improvement may be a significant reason for choosing certain regimens. [27]

Long-term use of combined hormonal contraceptives has been shown to reduce the risk of endometrial and ovarian cancer, with the protective effect persisting for many years after discontinuation. There is also evidence of a reduced risk of certain benign ovarian and endometrial tumors. These effects are attributed to a reduction in the number of ovulatory cycles and the protective effect of progestogen on the uterine lining. [28]

Hormonal contraception is widely used in the treatment of endometriosis, polycystic ovary syndrome, and a number of other gynecological conditions. These medications help control pain, reduce abnormal endometrial growth, and protect the uterine lining from chronic exposure to unbalanced estrogens. In these situations, the choice of method should consider both the contraceptive and therapeutic goals. [29]

Table 5. Main additional effects of hormonal methods

Direction	Possible effect
Cycle control	Regularity, reduced blood loss, reduced pain
Hematological health	Reducing the risk of iron deficiency anemia
Skin and hair	Improvement of acne and seborrhea by choosing the right gestagens
Cancer risks	Reducing the risk of endometrial and ovarian cancer with long-term use
Treatment of gynecological diseases	Support for endometriosis and polycystic ovary syndrome

[30]

Risks and safety of hormonal contraception

The most discussed risk of combined hormonal contraception is the increased risk of venous thrombosis. Estrogen affects the blood clotting system, increasing the concentration of certain factors and reducing the activity of natural anticoagulants. Consequently, the relative risk of venous thromboembolism increases compared to women not using hormonal contraception, although the absolute risk remains low in young non-smokers. [31]

The risk of thrombosis varies from person to person: it increases with age, obesity, smoking, hereditary thrombophilia, major surgery, and certain chronic diseases. Therefore, all modern medical eligibility criteria analyze these factors separately and, if the overall risk is high, recommend switching to estrogen-free methods, such as progestogen-only medications or intrauterine systems. [32]

Progestogen-only methods do not have an estrogenic effect and are generally considered safer in terms of thrombosis, although some injectable forms have been discussed as having a slightly increased risk in already vulnerable women. Their side effect profile most often includes irregular bleeding, possible moderate weight gain, and mood changes, but serious complications are rare. [33]

The possible impact of long-term hormonal contraception on the risk of breast and cervical cancer is also discussed. Current data indicate a slight increase in the relative risk of breast cancer with current use, which gradually decreases after discontinuation, while the risk of endometrial and ovarian cancer is significantly reduced. Therefore, the recommendations emphasize the need for individual consideration of cancer history. [34]

Common but less serious side effects include headache, nausea, breast tenderness, intermenstrual bleeding, and sometimes slight weight fluctuations. These symptoms typically appear during the first few months of adaptation and either subside over time or require a change in the specific medication or dosage. Current clinical guidelines recommend not immediately discontinuing the method due to mild symptoms, but discussing them with a doctor and evaluating alternatives. [35]

Table 6. Main risks of hormonal contraception and factors that increase them

Risk	What methods are particularly related?	Factors that increase the likelihood
Venous thrombosis	Combined methods	Age over 35 years, obesity, smoking, thrombophilia
Arterial events	Combined methods	Hypertension, diabetes with complications, migraine with neurological symptoms
Irregular bleeding	Purely progestogen methods	The first months of use
Minor weight gain	Purely progestogen injections	Individual predisposition, lifestyle changes
Mood changes and headaches	Any hormonal methods	Individual sensitivity

[36]

Medical acceptability and choice of method

To systematically evaluate which method is appropriate for whom, the World Health Organization and national societies have developed criteria for medical acceptability. These criteria categorize health conditions into categories from 1 to 4, where 1 means no restrictions and 4 means unacceptable risk with a given method. Such tables exist for all hormonal and non-hormonal methods, helping to standardize decisions and reduce the risk of error. [37]

For a healthy, non-smoking woman without serious chronic illnesses, most hormonal methods, including combination methods, are considered "no restrictions" or "with minimal restrictions." In this case, the choice depends primarily on preferences regarding the method of administration, frequency of administration, desired duration of action, and tolerance to potential side effects. [38]

In the presence of serious cardiovascular disease, severe hypertension, a history of thrombosis, active breast cancer, or severe liver disease, combination methods are typically considered in categories where the benefit does not outweigh the risk or where the risk is unacceptable. In such cases, preference is often given to progestogen-only methods or non-hormonal options, such as copper-containing intrauterine devices and barrier methods. [39]

Particular attention is paid to the postpartum period and breastfeeding, when the risk of thrombosis is particularly high and the effect of estrogen on lactation is undesirable. In these circumstances, recommendations generally allow the use of progestogen-only methods shortly after birth, while combined options are postponed until later, when the risk of complications decreases. [40]

The decision to prescribe a specific hormonal method should always be made taking into account the health risk of a possible pregnancy. For some women with severe medical conditions, an unwanted pregnancy carries the greatest risk, so even methods with certain limitations may be considered acceptable if alternatives are unavailable or significantly less reliable. [41]

Table 7. Example of application of medical acceptability categories

State	Combined methods	Purely progestogen methods	Intrauterine system with hormone
A healthy woman without risk factors	Category 1	Category 1	Category 1
Obesity without other serious factors	Category 2	Category 1	Category 1
History of venous thrombosis	Category 3 or 4	From category 2 to 3 depending on the details	Category 2 or 3
Severe hypertension	Category 3 or 4	Category 2 or 3	Category 2
Active breast cancer	Category 4	Category 4	Category 4

[42]

Special groups: adolescents, postpartum period, HIV infection

In adolescents, hormonal contraception often combines contraceptive benefits with acne treatment and cycle normalization. Age alone is not a contraindication, but it is important to pay special attention to education, regimen discussion, and possible changes in menstrual cycles. Guidelines emphasize that in adolescents, thrombosis factors and the impact on bone mineral density should be carefully considered when choosing long-term regimens. [43]

In the postpartum period, especially during breastfeeding, preference is usually given to progestogen-only methods and intrauterine systems. They do not contain estrogen, which can reduce milk production, and have a more favorable thrombosis risk profile compared to combined regimens. Medical acceptability criteria detail the time after birth at which each method is acceptable for breastfeeding and non-breastfeeding women. [44]

In obese women, hormonal methods remain an option, but the underlying cardiovascular risk increases, especially when combined with smoking and hypertension. In this group, combination therapies often move from the unrestricted category to the cautious or even contraindicated category, while estrogen-free methods and intrauterine systems often maintain higher acceptability. [45]

When treating HIV infection and taking antiretroviral drugs, it is important to consider potential drug interactions. Most current guidelines allow the use of many hormonal methods for HIV treatment; however, when certain treatment regimens are prescribed concurrently, hormonal levels may change. In such cases, careful selection of the method or preference for intrauterine systems and implants, which are less dependent on drug metabolism in the liver, is recommended. [46]

For perimenopausal women, hormonal methods can serve a dual purpose: contraception and partial correction of menopausal symptoms. At this age, the primary focus is on assessing cardiovascular risks and thrombosis. Combined regimens may be acceptable in some patients, but progestogen-only options and intrauterine systems are often considered, particularly when controlling heavy menstrual flow. [47]

Table 8. Preferred hormonal methods in individual groups

A group of women	Frequently considered methods
Teenagers	Low-dose combination tablets, implants
Breastfeeding after childbirth	Progestogen-only pills, injections, and intrauterine systems with hormones
Women with obesity	Purely progestogen-only methods, intrauterine systems
Women with HIV infection	Intrauterine systems, implants, some progestogen-only methods
Perimenopause	Purely progestogen-only methods, intrauterine system, sometimes combined regimens in low-risk settings

[48]

How to discuss hormonal method choice with your doctor

Before starting hormonal contraception, it's important to thoroughly discuss your health with your doctor. You should mention all chronic illnesses, including previous thrombosis, stroke, heart attack, migraine with neurological symptoms, surgeries, medications, and a family history of early thrombosis and cancer. This allows for the application of medical eligibility criteria and the immediate exclusion of potentially dangerous conditions. [49]

Personal preference also plays a significant role. Some women find it easier to take pills every day, others prefer an implant or intrauterine system and not have to worry about it for several years, and still others prefer a patch or ring. A doctor helps balance preferences with medical restrictions and explains how the regimen affects effectiveness and the frequency of side effects. [50]

The immediate life plan is also important. If pregnancy is possible within 1-2 years, methods that delay fertility restoration after discontinuation, such as some injectable regimens, may be less convenient. Conversely, if there are no plans to become pregnant in the coming years, it makes sense to consider long-acting options that minimize the risk of forgetfulness and ensure consistent effectiveness. [51]

It's helpful to discuss in advance which side effects are expected and which should prompt immediate attention. Irregular spotting during the first months of progestogen-only regimens is often normal, while sudden severe chest or leg pain, shortness of breath, or severe neurological symptoms require urgent attention. A clear understanding of these limits reduces anxiety and increases safety. [52]

Finally, it's important to remember the combination of hormonal contraception and protection against infections. Doctors typically recommend condoms for anyone who isn't in a stable, mutually monogamous relationship with a verified partner. This combination is called double protection, as it simultaneously prevents pregnancy and reduces the risk of sexually transmitted infections. [53]

Frequently asked questions about hormonal contraception

Does long-term use of hormonal contraception lead to infertility?
Most data show that in women without underlying fertility problems, ovulation and fertility return within weeks or months after discontinuing the method. The exception is some injectable regimens, where the delay in recovery may be longer, but this is temporary. If pregnancy does not occur within a year of discontinuing the method despite regular sexual activity, the problem is most often related to other factors, not the previous contraception used. [54]

Is weight gain inevitable while taking hormonal contraceptives?
Current research does not confirm significant weight gain in all women using hormonal contraception. Minor weight changes are more often associated with fluid retention, changes in appetite, and lifestyle. If weight gain is noticeable and persistent, a doctor may suggest switching methods or simultaneously working on diet and physical activity. [55]

Should I take "breaks" if contraception is well tolerated?
In healthy women without risk factors, there is no evidence that taking breaks from hormonal contraception improves health or reduces risks. On the contrary, such breaks increase the likelihood of unwanted pregnancy. Current protocols allow for long-term, uninterrupted use, provided regular monitoring and the absence of new contraindications. [56]

Is it possible to start hormonal contraception immediately, without waiting for your next period?
A number of recommendations describe a "quick-start" approach, whereby the method is started on any day when there is sufficient certainty that you are not currently pregnant. In this case, barrier contraception is temporarily added for a few days and a pregnancy test is performed if necessary. This approach facilitates access to methods and reduces the risk of "lost" cycles. [57]

Does hormonal contraception protect against sexually transmitted infections?
No. Neither pills, patches, implants, nor intrauterine systems prevent sexually transmitted infections. To protect against HIV and other infections, condoms should be used every time you have sex, especially with different partners. Therefore, when discussing hormonal contraception, your doctor will always raise the issue of double protection. [58]