Virtual Medical Centre

Contraception (Birth Control)

• What are contraceptives?
• Who uses contraceptives?
• Prevalence of contraceptive use
• Benefits of contraceptive use
• Limitations and side effects of contraceptive use
  • Limitations
  • Side effects
  • Health risks
• Important considerations in choosing a contraceptive method
  • General considerations
  • Medical history and examination
  • Considerations for adolescent women
  • Considerations for women who have recently given birth
  • Considerations for women nearing menopause
• How do contraceptives work?
  • Hormonal contraceptive methods
  • Barrier methods

What are contraceptives?

Contraceptives, also commonly referred to as family planning or birth control methods, are a range of devices, procedures and medications which assist women to prevent pregnancy. The way they prevent pregnancy differs, but most methods are either hormone or barrier dependent.

Contraceptive methods which are hormone dependent may either:

1. Alter the body's hormones so that an egg cannot be fertilised. Contraceptives that do this are commonly known as hormonal contraceptive methods; or
2. Monitor the changes to hormone levels which naturally occur throughout the menstrual cycle, and avoid sex during periods when it is possible to become pregnant. These known as fertility awareness methods.

Barrier methods on the other hand rely on a physical barrier, which prevents the male's sperm and the female egg coming into contact during sexual intercourse, and in doing so, prevents fertilisation.

Hormonal contraceptives are typically long term methods which provide protection at all times whilst they are being taken, regardless of whether the user is sexually active.

Emergency contraceptives are also hormonal contraceptives which can be taken immediately (within five days) after unprotected sexual intercourse to prevent pregnancy occurring.

Barrier methods are inserted or applied just prior to sexual intercourse. They must be applied before each act of intercourse to protect against pregnancy.

Who uses contraceptives?

Hormonal contraceptives are used by fertile women (i.e. women who experience menstrual cycles, typically aged 15-49) who wish to prevent pregnancy. They are typically used by women who are regularly sexually active, and therefore require ongoing protection from pregnancy.

Barrier methods of contraception are also used by women of reproductive age who wish to prevent pregnancy. However, they are particularly appropriate for women who also need to protect themselves from STIs (i.e. women who have partners of unknown STI status).

Prevalence of contraceptive use

In Australia, more than 70% of all adult women and 95% of fertile women use a method of contraception. Oral contraceptive pills, used by 33.6% of women who use contraception, are the most commonly used method, followed by female sterilisation (22.5%), condoms (21.4%) and vasectomy (19.3%). Around 19% of Australian women who have ever had sex have used an emergency contraceptive, and 53% of emergency contraceptive users have used this method only once.

Benefits of contraceptive use

Contraceptives allow women to control their fertility and thus decide when and if they bear children. Enabling women to control their fertility and particularly to adequately space births (i.e. have a break from pregnancy for at least two years after childbirth) has numerous health benefits for women and their infants.

Women are better positioned to participate in social life, find employment and attain education when they are using contraceptives and do not risk falling pregnant. As these activities generally increase women's status in society, contraceptives indirectly promote the rights and status of women.

Women who become pregnant very quickly after childbirth have worse pregnancy outcomes (e.g. they are more likely to suffer from a serious medical condition or to die during pregnancy). Their babies are also more likely to have poor health outcomes (e.g. to be born at a low birth weight). The World Health Organisation estimates that globally, 100,000 maternal deaths could be averted every year, if all women who did not want any more children were able to avoid pregnancy. These deaths occur for the most part in developing countries where contraceptive coverage is low.

There are a number of non-reproductive health benefits associated with the use of some contraceptive methods. Combined (i.e. oestrogen and progesterone) hormonal methods are associated with a decreased risk of ovarian and endometrial cancers. Progesterone only injections also protect against these cancers and also against uterine fibroids. Contraceptive implants and female sterilisation have been shown to reduce the risk of pelvic inflammatory disease.

Enabling women to avoid pregnancy prevents the psychological health effects of unwanted pregnancy and reduces the demand for abortion. In Australia, 22.6% of women who have ever been pregnant have terminated at least one pregnancy, indicating a significant proportion of Australian women have at some stage in their life dealt with emotional stress related to unwanted pregnancy.

The ability to control their fertility also allows women to better control other aspects of their life, for example to decide when and for what reasons they get married. Since contraceptives became widely available in the 1970s, women's fertility and marriage patterns have changed considerably in Australia. Women now marry and have children later in life and on average, have less children. These demographic changes are likely to have lessened the emotional and economic burden of child-rearing, as families now typically have longer to accumulate financial resources prior to childbirth. Smaller family sizes also mean that parents have more time and resources to dedicate per child.

Limitations and side effects associated with contraceptive use

Limitations

Contraceptives must be accessed and then used consistently and correctly to effectively protect against pregnancy. Even in countries like Australia where contraceptives are inexpensive and widely available, around 5% of women who do not wish to become pregnant are not using contraceptives. Some 22.6% of women in Australia who have ever been pregnant, have terminated at least one pregnancy and many of these pregnancies may have been prevented in the first place if the women were using effective contraceptive methods.

There are also limitations regarding the effectiveness of various contraceptive methods, and no method is 100% effective. For example, male condoms are thought to be effective in protecting against unwanted pregnancy in 97% of cases and the effectiveness of hormonal contraceptive methods is much higher.

One of the key limitations of most contraceptive methods (male and female condoms being the exception), is their failure to protect against STIs. Individuals who have sex with partners of unknown STI-status (i.e. partners whom they have not been for an STI check with) should use condoms for STI prevention. Condoms can be used either alone or in combination with another contraceptive method.

Side effects

There are some, typically minor, side effects associated with some forms of contraceptives, and particularly with hormonal methods. These include:

• Breast tenderness;
• Nausea;
• Acne;
• Headaches;
• Dizziness;
• Irregular menstrual bleeding;
• Abdominal bloating or pain;
• Mood changes;
• Reduced libido.

The side effects of each method are detailed more fully on pages dedicated to each method- see below for further information.

Health risks

There are also some health risks associated with various forms of contraceptives. Combined oral contraceptives are associated with very or extremely rare cases of:

• Blood clots;
• Heart attack;
• Stroke.

Intrauterine contraceptive devices (IUDs) are associated with rare cases of pelvic inflammatory disease [LINK to URL: Pelvic Inflammatory Disease] and may also increase the risk of anaemia in women who already have low blood haemoglobin.

Contraceptive methods (with the exception of sterilisation) do not affect fertility irreversibly. With most methods, fertility returns immediately after contraceptive use has stopped.

Important considerations in choosing a contraceptive method

General considerations

The aim of using contraceptives is to prevent pregnancy. Pregnancy prevention is most likely if a contraceptive method which suits the individual's lifestyle, sexual behaviours and other characteristics is chosen.

There are many different contraceptive methods available and choosing the most suitable method may be confusing. The most appropriate contraceptive method will depend on characteristics of the woman wishing to prevent pregnancy, for example her age, parity, future fertility desires and health. The woman's lifestyle is also a determining factor, and other factors, for example the patient's geographic location and financial situation may also play a role.

When choosing a contraceptive method it is useful to speak to your doctor about contraceptive options. Many contraceptives also require a prescription. A doctor can offer advice on which method/s are suitable and about the benefits and limitations of each available method. Many women will have heard about and/or be interested in using a particular method, and women who have a method in mind should let their doctor know that they would prefer this method. Unless there is a medical reason not to, a doctor will usually prescribe a woman's preferred method.

Women assessing contraceptive options should bear in mind that the best contraceptive method is not necessarily the one which is the most effective in theory. In order to prevent a pregnancy in the real world, contraceptive methods must be used both correctly and consistently. For example, although combined hormonal contraceptives are the most effective means of preventing pregnancy, they are also more likely than other methods to cause side effects. Globally, side effects are the most common reason women stop using contraceptives. In Australia, some 23% of fertile women who do not wish to become pregnant and do not use contraceptives, cite side effects as their reason for non-use. Thus, for women who experience side effects, combined hormonal contraceptives may be an inappropriate method, despite their high level of effectiveness.

A woman must fully consider her ability to use the contraceptive method correctly and consistently. Women who are forgetful or have erratic schedules (e.g. shift workers) may find it difficult to comply with contraceptive regimes which require daily action (i.e. oral contraceptive pills), particularly if that action has to be taken at the same time each day (e.g. the progesterone-only oral contraceptive must be taken at the same time +/- 3 hours). Women who wish to hide their contraceptive use from partners may be better able to use a method which requires less frequent administration than oral contraceptive (e.g. an injection, implant or intrauterine device (IUD)).

Similar to women in steady relationships, women who have casual sexual partners need contraceptive protection. However women who have sex with casual or multiple partners also have an increased risk of contracting STIs. The need to protect against STIs is thus an important consideration in terms of contraceptive choice for these women, who should use male or female condoms to protect against STIs, either alone or in conjunction with another contraceptive method. Women who are concerned about their ability to enforce condom use at every act of sexual intercourse (e.g. commercial sex workers, young women with limited skills in negotiating contraceptive use) should use another contraceptive method (e.g. oral contraceptive pills) in addition to condoms.

Medical history and examination

When a woman visits a doctor for a contraceptive prescription, the doctor will usually begin by asking questions about the woman's general health. This allows the doctor to assess whether the woman has any health issues which may make using some types of contraceptives dangerous. The doctor is likely to ask about:

• Cardiovascular risk factors;
• Other medications being taken;
• Allergies;
• Health problems, including:
  • Migraines (contraindication for hormonal methods);
  • Gonorrhoea (contraindication for IUD);
  • Chlamydia (contraindication for IUD);
  • Acquired immune deficiency syndrome without antiretroviral treatment (contraindication for IUD).

The woman's height, weight and blood pressure are often also checked, as these may influence the choice of contraceptive method, or the period for which it is effective (e.g. implantable contraceptives are effective for a shortened period of time in women who weigh > 70 kg, compared to women who weigh < 70 kg).

Pelvic examinations are not typically necessary, unless indicated by the method (e.g. pelvic examination is necessary to select a correctly fitting diaphragm). Screening for cervical cancer (i.e. a pap smear) is not a prerequisite for contraceptive prescription as it has no bearing on the effectiveness of contraceptive methods.

Considerations for adolescent women

While only around 5% of babies born in Australia are born to adolescent mothers, statistics show that one quarter of all adolescent women become pregnant unintentionally. Around half of these pregnancies are terminated.

Adolescent women are at a particularly high risk of becoming pregnant when they do not want to be, as they may be under-educated about contraception and pregnancy, or scared to access contraceptives. Their lifestyle and restrictions may make it more difficult to use some contraceptive methods. 

Young women assessing their contraceptive options should consider the following points:

• Young women are often more sensitive to the side effects of hormonal contraceptives than older women. When taking hormonal contraceptives for the first time, young women should be prepared to experience some side effects (which typically diminish over time). Women who expect side effects are better prepared for them and less likely to stop using contraceptives when they experience them;
• Young women may find it more difficult to take contraceptive pills on a daily basis (e.g. because they are scared that their parents will find the pills). Contraceptive methods which can be taken without others knowing, (e.g. injectables) may therefore be more acceptable for at least some adolescent women;
• Young women, and particularly those who are not married, are more likely than their older counterparts to have multiple sexual partners. This increases their risk of STIs and using contraceptive methods which also protect against STIs (male and female condoms), or dual methods of contraception (e.g. oral contraceptive pill and condoms) is particularly important for young women with multiple sexual partners;
• Young women may have less control over when they have sex and whether they can access contraception. Young women may therefore have a greater need for emergency contraceptives. However, research amongst Australian university students revealed poor knowledge of emergency contraception. Many students were unaware that emergency contraceptive pills are available over the counter, and that they could be used for days after unprotected intercourse, not only the morning after. Young women who are using contraceptive methods which may occasionally fail (e.g. condom) should be aware of a place where they can access emergency contraceptive pills and may wish to discuss the benefits and limitations of this method with a doctor;
• Young women are more likely to develop complications during pregnancy than their older counterparts, as their bodies are still growing. Preventing pregnancy in young women is thus extremely important as it is also likely to prevent high-risk pregnancies which result in complications.

Considerations for women who have recently given birth

Preventing pregnancy in the two years after the birth of the most recent child is particularly important, as women who become pregnant too soon after giving birth have poorer pregnancy outcomes, and their infants have poorer health outcomes. When choosing a contraceptive method, these women should take the following into account:

• The oestrogen in combined oral contraceptives impairs lactation. Therefore oestrogen-based methods are not recommended for breastfeeding women as they may negatively affect the health of the feeding baby;
• Progesterone only contraceptives do not affect breast milk production;
• While there is no evidence that progesterone affects the development of a breastfed infant, its affects on the infant's brain development have not been adequately studied;
• Progesterone only methods are usually not recommended within six weeks of childbirth for women who are breastfeeding;
• Women that gave birth childbirth six weeks or longer ago can safely use progesterone only methods, even if they are breastfeeding;
• Exclusive and regular breastfeeding provides a degree of contraceptive protection in the first six months after childbirth. However, women who wish to increase the reliability of their contraceptive protection should use an additional method.

Considerations for women nearing menopause

As a woman approaches menopause, her menstrual cycle typically becomes irregular and may disappear for months at a time. This usually occurs between 45-55 years of age, and some 50% of women will be infertile due to menopause by age 50, and 96% by age 55. A woman is considered post-menopausal and infertile when she has not experienced a menstrual cycle for 12 consecutive months.

Until a woman is confirmed as post-menopausal, it is important that she continue to use contraceptives if she wishes to prevent pregnancy. As women approaching menopause typically do not want any more children and pregnancy at this stage of life comes with a high risk of complications, preventing pregnancy amongst this group is extremely important. The following points should be considered by women approaching menopause:

• Permanent methods of contraception (e.g. male or female sterilisation) may be particularly suitable for women who do not wish to have any more children;
• Older women are more likely to have conditions of the reproductive system which contraindicate sterilisation;
• For women over 35 years of age who smoke or experience migraine headaches, hormonal methods are often unsuitable;
• Emergency contraceptives can be used safely by older women, even older women for whom long term hormonal methods are unsuitable;
• Fertility awareness methods are unsuitable for women approaching menopause as their menstrual cycle is irregular.

How do contraceptives work?

Hormonal contraceptive methods

Hormonal contraceptives work to prevent pregnancy by changing the hormonal environment of the woman's body so that ovulation and therefore conception cannot occur. Ovulation occurs during the menstrual cycle, in response to changing hormone levels. Oestrogen and progesterone both play an important role. By taking hormonal contraceptives, a woman artificially changes her body's natural hormone levels, in such a way that the hormonal balance necessary to trigger ovulation does not arise.

Barrier methods

Barrier methods work by providing a barrier which prevents the mixing of sexual fluids during intercourse. As the male partner's sperm never come into contact with the female partner's oocyte, pregnancy is prevented.