The provision of contraception to adolescents requires specific attention. Adolescents require contraceptive methods which are safe, effective and simple to use. While long-acting reversible contraceptive methods are preferable, they should have a choice and not be forced or mandated especially in situations where this may compromise safety. After counselling they should have the ability to choose any method of contraception. Under the appropriate circumstances, each method of contraception may have a place. This chapter will be devoted to evaluating the most current scientific rationale for the indication for use of each method of contraception in adolescents.
Introduction
Humans become fertile during adolescence. Fecundity has changed very little over thousands of years when corrected for nutritional and environmental factors. A new development is that many people want to avoid pregnancy for a significant period of their early reproductive years. The options for doing this range from complete abstinence from sexual activity to a vast range of contraceptive options from simple mechanical methods to complete cessation of fertility, if deemed necessary, in rare instances. The purpose of this review is to examine all these methods in terms of practicality and efficacy, both theoretical and actual. As individuals differ considerably, the final choice will, however, always be a compromise between what may be best theoretically and the practicality of the choices and desires of the individual.
The World Health Organization (WHO) defines adolescence to be from age 10 to 19 years. For the purpose of contraception, it is probably from 11 or 12 to 19. Adolescents are rarely pubescent and voluntarily sexually active before this age. This review evaluates the methods of contraception in this group. We will not discuss whether or not adolescents, especially at the lower age range, should be sexually active. Those who are should be able to access appropriate services so that they can avoid unwanted pregnancy and the difficulties and complications that it will impose upon both them and often society at large.
Approach to the adolescent requesting contraception
Adolescents have a right to request and receive unbiased contraceptive counselling. They also have the right of choice concerning which contraceptive they wish to use . The role of the contraceptive counsellor is to supply them with the known information of what would be best for those in their situation. They can then choose whether to align themselves with this choice or not. While we can advise the use of a long-acting reversible contraception (LARC) method whenever possible, it is ultimately the adolescent’s choice to use one of these methods . Younger adolescents, in particular, should be encouraged, but never obligated to inform parents or guardians of their decision to use pharmacologically active methods of contraception as it may potentially interfere or interact with other medication which they might require.
This review examines the provision of contraception to adolescents in terms of the latest scientific findings. It does not necessarily conform to the guidelines of any particular statutory body or bodies. These should be independently consulted where necessary. It also does not conform to any specific dictates of conscience. These should also be consulted independently.
Approach to the adolescent requesting contraception
Adolescents have a right to request and receive unbiased contraceptive counselling. They also have the right of choice concerning which contraceptive they wish to use . The role of the contraceptive counsellor is to supply them with the known information of what would be best for those in their situation. They can then choose whether to align themselves with this choice or not. While we can advise the use of a long-acting reversible contraception (LARC) method whenever possible, it is ultimately the adolescent’s choice to use one of these methods . Younger adolescents, in particular, should be encouraged, but never obligated to inform parents or guardians of their decision to use pharmacologically active methods of contraception as it may potentially interfere or interact with other medication which they might require.
This review examines the provision of contraception to adolescents in terms of the latest scientific findings. It does not necessarily conform to the guidelines of any particular statutory body or bodies. These should be independently consulted where necessary. It also does not conform to any specific dictates of conscience. These should also be consulted independently.
Over-the-counter (OTC) and self-determined contraception
Most adolescents seeking contraceptive advice will already have tried one or more of these methods. These may include abstinence, male and female condoms, spermicidal gels and the contraceptive sponge . Some may have attempted to use fertility-based awareness methods, usually by rough calculation rather than by formal plotting of their menstrual cycles, with or without cervical mucus assessment. They may have used over-the-counter (OTC) hormonal methods for emergency contraception (EC). This will be examined further in the section devoted to emergency contraction.
The disadvantages of OTC methods are that they have high failure rates even when used diligently, which may be less likely in adolescents. The biggest problem of OTC methods, however, is that they are short-acting reversible contraceptive (SARC) methods. In recent years, we have come to understand just how important the role of LARC methods is in the prevention of unwanted pregnancies, especially in adolescents . Adolescents are unlikely in most cases to be motivated enough to use OTC rigorously especially if they realise the deficiencies of the methods. Most female adolescents who have decided to have regular sexual relationships will seek help for contraception either alone or with their sexual partners.
The role of the health-care provider in guiding the adolescent to a choice of contraceptive method with which they are comfortable and which is in her best interests is discussed in the following sections of this review.
Short-acting reversible contraception
- i)
Oral hormonal contraception
This is the typical birth control method for adolescents in developed countries . Around 20% of Western adolescents use oral contraceptive pill (OCP), which represents about 40% of all adolescents who use any form of contraception . These figures vary in different countries. Advertisements for the OCP usually depict older adolescent women. For the last few decades, the OCP has been the accepted method of contraception choice for health-care providers and clinics in affluent high-literacy countries. This was strengthened by the ease of supply, the perceived safety and the later realisation that previously mandated tests, for example, cervical cytology smears, tests for sexually transmitted infections and metabolic tests, while desirable, were not a real necessity. The alternatives of intrauterine devices (IUDs) which were considered too risky, barrier methods considered to be clumsy and less effective and injectable progestogenic contraceptives also considered to be somewhat risky, were thus deemed to be less advantageous, and OCPs were to be preferred, if only by default. In recent years, the pendulum has swung away from OCPs primarily because they have not had sufficient impact in reducing unwanted pregnancy in this specific group .
The OCP is a good choice for the motivated adolescent if there are no contraindications present. The question of which one to choose has become somewhat easier recently . After their introduction in the early 1960s it became clear that those oral contraceptive pills with a higher dose of oestrogen, mestranol initially and then ethinyl estradiol (EE 2 ), were associated with a higher risk of venous thromboembolism (VTE). This was solved by reducing the dose of EE 2 from 50 μg, and in some cases lowering it further, to 15 μg. A number of different types of synthetic progestogen were used initially and for a while they were deemed to be fairly similar after allowing for potency ( Tables 1 and 2 ) .
| First generation | Second generation | Third generation | |
|---|---|---|---|
| Pregnanes | Estranes | Gonanes | Gonanes |
| Chlormadinone acetate | Norethindrone | dl -norgestrel | Desogestrel |
| Cyproterone acetate | Norethindrone acetate | Levonorgestrel | Norgestimate |
| Megestrol acetate | Ethynodiol diacetate | Gestodene | |
| Lynestrenol | |||
| Norethynodrel | |||
| 19 Nor-progesterones a | Gonanes a | Estranes a | Spironolactone derivative |
|---|---|---|---|
| Promegestone | Norelgestromine | Dienogest (non-ethylated) | Drospirenone |
| Trimegesterone | Etonogestrel | ||
| Nesterone | |||
| Demegesterone | |||
| Nomegestrol acetate |
By 1995 it had become apparent that some of the so-called third-generation progestogens, that is, gestodene and desogestrel were more likely to be associated with VTE as compared to the earlier types . The earlier formulations were presented in monophasic and multiphasic formulations, without any evidence of real benefit for the multiphasic formulations. More recently, further evidence has emerged that the ‘third’- and ‘fourth’- generation progestogens and cyproterone acetate, a pregnane ( Table 1 ), are in some studies associated with a higher relative risk of producing venous and possibly arterial thrombosis but there is some disagreement on this .
A good choice of OCP will usually be a second-generation OCP with levonorgestrel (LNG) and EE 2 . The old 30 μg EE 2 /150 μg LNG which was introduced in 1973 is a common starting point. Where necessary the older first-generation estranes may also be an option ( Table 1 ). The argument that third- and later-generation OCPs only increase the very small risk of thrombosis by a factor of two and that pregnancy carries a far higher risk for VTE is not relevant . There is currently insufficient information on those OCPs containing fourth-generation progestogens whose oestrogen components are estradiol or estradiol valerate.
- ii)
Non-oral hormonal contraception
- a)
Vaginal ring
- a)
The Nuvaring ® is a silastic ring containing 11.7 mg etonogestrel ( Table 2 ) and 2.7 mg EE 2 . The daily release rate is 120 μg/day etonogestrel and 15 μg/day EE 2 . It is kept in the vagina for 3 weeks out of every 4 and is a reasonable alternative to the OCP. It is well tolerated. As etonogestrel is the active metabolite of desogestrel, there is some concern regarding its possible effects on venous thromboembolism .
Two studies from the USA found that the risk is no more than LNG-containing OCPs . One study from Denmark found that it has the same risk as the third-generation progestins such as desogestrel and gestodene and also drospirenone .
It should be reserved for those who have difficulties swallowing or complying with OCPs.
- b)
The Transdermal Contraceptive Patch
- b)
The Ortho-Evra ® patch is a matrix transdermal system which contains 6 mg norelgestromin and 0.75 mg of EE 2 . Norelgestromin ® is a metabolite of norgestimate ( Table 2 ). The advantage of the patch and the vaginal ring is that, unlike oral preparations, the active hormones do not undergo first pass metabolism in the liver. This is a theoretical benefit but there are no other specific advantages. The patch is changed weekly for 3 weeks and omitted for 1 week. Like the NuvaRing, its main benefit is among those adolescents who have difficulty with pill compliance. It has also been implicated in venous thromboembolism but whether it is significantly more risky than EE 2 /LNG oral combinations is not known . It showed the same degree of thromboembolism as norgestimate-containing pills in one study and twice as much as norgestimate-containing pills in another . The choice between the patch and the ring is therefore largely one of convenience.
LARC methods
A LARC is a method that requires administration less than once per cycle or month. LARC methods combine reversibility with high effectiveness as they do not depend a great deal on compliance or correct use . While this is a benefit to almost all contraceptive users it is very important in adolescents . Adolescents are more likely to forget and wrongly use SARC contraceptive methods. This is borne out by the dramatic reduction in teenage pregnancy rates seen when LARC methods were introduced as in the CHOICE program in St Louis, USA .
- a)
Injectable contraceptives
Injectable hormonal contraceptive is more reliable than SARC. The user does not have to remember to administer it on a daily basis but it is reliably effective for a term of months rather than years. The are two progestogenic injectables available. These are the more widely used Depot-medroxy progesterone acetate (DMPA) and nor-ethisterone enanthate (NET-En). Although they are often classified together, they are significantly different.
- 1)
Depot-medroxy progesterone acetate
- 1)
Although injectable contraceptives are classified as a LARC-method, it does not have the equivalant good continuation rates than other LARCs. DMPA was initially perceived to be free of thrombotic side effects and does not interfere with breast-feeding . This made it ideal for use in developing countries with rapidly expanding populations. The problem of osteoporosis and the possibility that it predisposes the user to infection with human immunodeficient virus (HIV) have led to some doubt about its large-scale use . The outcome of large-scale trials are awaited before we will know just how significant this risk is. While the 3-monthly injection routine for DMPA 150 mg is convenient, its use in adolescent women who may not have an adequate calcium-enriched diet and may be exposed to HIV especially in communities where condom use is minimal is worrying, especially if other methods are available. All contraceptive users should be encouraged to use dual protection.
- 2)
NET-En
- 2)
NET-En is an ester of the first-generation estrane progestin norethisterone (norethindrone) in oily suspension. NET-En is an estrane and as such has an approximately 5% transformation into oestrogen . This may protect the user from osteoporosis and exposes her to a very small theoretical risk of thrombosis. In addition, its effect on lipids is similar to that of other 19 nor-testosterone derivatives including the gonanes ( Table 1 ).
- b)
The intrauterine device
The IUD has had a long and turbulent history as a birth control method since its introduction by Richter and Grafenberg in the early 1900s . In the early 1960s, IUDs were manufactured of thermoplastics (polyethylene and polypropylene) and became widely available. The most prominent was the Lippies Loop ® . The problem with the earlier IUDs was that the dimensions were based on anatomical models of the uterus reported by Dickinson . These resulted in the manufacture of IUDs which were often too large even for the multiparous uterine cavity but definitely too large for the adolescent nulliparous uterine cavity .
One of the major advantages is that continuation rates are very good. Table 3 summarises the continuation rates reported in a number of studies in adolescent nulliparous adolescent women . Table 4 shows the dimension of various IUDs in use worldwide. There is good evidence that using devices which more closely match the dimensions of the uterine cavity will produce better results . The average length of the nulliparous uterine cavity determined by the mechanical methods and by ultrasound is 33.73 mm and 37 mm, respectively . The average maximum transverse diameter of the nulliparous uterine cavity by mechanical methods and by ultrasound is 25.1 mm and 28.2 mm respectively .
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