Sexual health, contraception, and teenage pregnancy
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《英国医生杂志》
The median age for first sexual intercourse in the United Kingdom dropped during the early 1990s and is now stable at around 16 years for both men and women. The disparity between the sexes observed in the early 1990s has diminished. Before the age of 15, about 18% of boys and 15% of girls report having had full sexual intercourse, with similar proportions having engaged in oral sex.
Proportion of UK teenagers who first had sexual intercourse by age 16 years, 1964-98
Having sex for the first time at an early age is often associated with unsafe sex, in part through lack of knowledge, lack of access to contraception, lack of skills and self efficacy to negotiate contraception, having sex while drunk or stoned, or inadequate self efficacy to resist pressure.
About 10% of boys in the United Kingdom report that they were drunk or stoned when they first had sex, and 11% of girls report being pressurised by their partner when they first had sex. Of those under 16 years who have ever had sex, about a third to a half of both sexes report ever having had unsafe sex.
Percentages of 14 year olds in Scotland engaging in various sexual activities
Sexually transmitted infections
Considerable rises in the incidence of STIs, particularly chlamydia, have led to a major public health problem in the United Kingdom. Although rates in the under 16s have remained low, rates in 16-19 year olds and 20-24 year olds almost trebled in men and more than doubled in women during 1995 to 2001. Some studies suggest that 30-40% of sexually active teenage girls in high risk groups are infected.
Risk factors for sexually transmitted infections in adolescence
Gonorrhoea, and to a lesser extent genital herpes, has shown similar increases in incidence. The highest rates of STIs are among black Caribbean and black African young people, suggesting that cultural and socioeconomic factors play a major role in the risk of acquiring and in protection against STIs.
Rates of uncomplicated chlamydia infections in United Kingdom by age, 1995-2001
Clinical presentations of STIs in adolescents are similar to those in adults. It is important to note that chlamydia, often asymptomatic in older adolescent girls and women, usually presents with a vaginal discharge in young adolescent girls.
Teenagers assess and evaluate risk differently from adults and health professionals: they would rather reduce their risk of being excluded from the "in-group" or of looking immature than take notice of any perceived health risks
Early detection and treatment of curable STIs, such as chlamydia, can reduce the risk of further complications, such as infertility and ectopic pregnancy. With the easy availability of highly sensitive new nucleic acid amplification tests on voided urine, current UK recommendations support the opportunistic screening of all sexually active adolescent females attending general practice surgeries and genitourinary medicine and family planning clinics, regardless of whether they have symptoms. Screening young men without symptoms remains more controversial, although many suggest opportunistic screening similar to that provided for young women.
Clinical features of sexually transmitted infections in adolescents
Teenage pregnancy
The incidence of teenage pregnancy across Europe varies considerably. The United Kingdom has the highest rate in western Europe and is lower only than Bulgaria, Russia, and Ukraine in Europe as a whole. Throughout most of western Europe, teenage birth rates fell during the 1970s, '80s, and '90s, but in the United Kingdom, rates have remained high—at or above the level of the early '80s.
Live birth rate to women aged 15-19 years, 1973-96
It is important to recognise that for some young women, particularly from certain ethnic or social groups, teenage pregnancy can be a positive life choice. Rates of teenage pregnancy within marriage are high, for example, in some South Asian ethnic groups in the United Kingdom. However, for many other young women, the costs of teenage pregnancy can be very high, particularly when linked with poverty. These risks include poorer outcomes for the children of teenage mothers as well as for the mothers themselves.
Births per 1000 women aged 15-19 years, 1998
Infant mortality among babies of teenage mothers is about 60% higher than among the babies of older mothers. These infants are also more likely to have lower birth weights, have childhood accidents, and be admitted to hospital during childhood. In the longer term, the daughters of teenage mothers are more likely to become teenage mothers themselves.
Adult outcomes of teenage pregnancy compared with a reference level for women who give birth at age 23-32 and had no childhood poverty
Prevention of unwanted teenage pregnancies is a high priority in many countries. In the United Kingdom, strategies are based on the cycles of social exclusion and disadvantage that both cause and follow teenage pregnancy.
High quality evidence shows that health promotion behavioural programmes using peer educators of a similar age reduce the prevalence of sexual activity at age 16 years. Although programmes that promote abstinence have a logical appeal, no high quality studies have shown the effectiveness of such approaches, and such programmes are not seen as acceptable by many teenagers or professionals as they potentially limit young peoples' rights and autonomy.
Risk factors for teenage pregnancy
Factors known to protect young people from teenage pregnancy include higher levels of connectedness with school and family; long term, stable relationship with a partner; and strong religious beliefs
Contraception
In the United Kingdom about 75% of young people in early adolescence and 85% in mid-adolescence, of both sexes, have reported that they used an effective form of contraception the last time they had sex.
Proportion of adolescents using contraception at first intercourse
Teenagers are relatively poor users of both barrier and hormonal contraceptives. Condoms remain the contraceptive of choice of young people; over 75% reported that they used condoms at their last sexual intercourse (15% reported using the oral contraceptive, 1% injectable contraception, and 6% emergency contraception).
Condoms remain the contraceptive of choice of young people, though the combined use of condoms plus the contraceptive pill is probably the most effective option
The first time a young person has sex is one of the riskiest times for young people in the United Kingdom: half of the under 16s and a third of those aged 16-19 use no contraception the first time they have sex, as much as double the rates in other developed countries, including the United States.
Proportion of adolescents using contraception at first intercourse
Health promotion targeted at teenagers and the provision of free condoms improves contraceptive use by teenagers. The most appropriate contraceptives for most young people are likely to be condoms and the contraceptive pill. However, teenagers have a relatively high failure rate with both these methods because of "technical problems" (condom failure and irregular use of the pill). Because of this, some countries are promoting the "double Dutch" method—using condoms plus oral contraception to protect against both pregnancy and STIs.
Promoting contraception in primary care
Emergency contraception is not a substitute for a regular form of contraception and does not protect against STIs. Access to emergency contraception, however, is an important and effective preventive measure against an unwanted pregnancy. In the United Kingdom, knowledge of emergency contraception is low among young people—for example, less than half know about the 72 hour "window of opportunity." Young women aged 16 and over can obtain emergency contraception over the counter at pharmacies. However, for girls under age 16, such contraception is available only on prescription (either from doctors or, in exceptional circumstances, from approved pharmacists), thus imposing substantial limitations on its use by young teenagers at risk.
Good evidence to support current practice is limited. Increasing numbers of people believe that campaigns and educational programmes that promote postponement or temporary abstinence much more strongly than the current British programmes do might result in greater health benefits. ABC programmes (Abstinence, Be faithful, and if not, use a Condom) seem to have been remarkably successful compared with promotion of barrier contraception in some African countries, and the politically driven "abstinence-only" campaigns in the United States have coincided with falls in teenage pregnancy rates without the increases in STIs seen in the United Kingdom.
Guidance from UK Department of Health*
Evidence is increasing that, although abstinence campaigns may delay young people's first sexual intercourse, they may also increase their risk of having unprotected sex when they do begin having sex
Providing sexual health services to adolescents
Sexual health services for young people must be available in general practice in addition to specialist services. A recent study reported that over 90% of pregnant teenagers had discussed contraception with their general practitioner in the year before becoming pregnant, confirming primary care as the main provider of health services. Those at risk of pregnancy are also at risk of STIs, and it would be logical to provide both contraceptive and STI testing services together.
Desirable features of sexual health services for adolescents
Siting of services may be critical. Because of reluctance about being identified as using a sexual health service, young people may prefer to attend a general primary care clinic rather than a specialist service, even if the primary care clinic is not as youth friendly. The sex of the health professional also seems to be important, with a tendency for primary care or family planning services to be used by young women, while young men may simply buy condoms from pharmacies or vending machines.
Providing sexual health and contraceptive services in an "age appropriate" environment and manner is particularly important for adolescents, as they will simply not use services they regard as inaccessible or unfriendly. Young people report that confidentiality, a non-judgmental approach, informality, accessibility, and the ability to choose whether they see a male or female health worker are the most important factors in deciding whether to use services.
Further reading
? Rogstad KE, Ahmed-Jushuf IH, Robinson AJ. Standards for comprehensive sexual health services for young people under 25 years: UK national survey. Int J STD AIDS 2002;13: 420-4.
? Social Exclusion Unit. Teenage pregnancy report. London: Stationery Office, 1999.
? Toumbourou J, Patton GC, Sawyer S, Olsson C, Webb-Pullman J, Catalano R, et al. Evidence based health promotion. No 2. Adolescent health. Melbourne: Department of Human Services, Victoria, 2000.
? Trust for the Study of Adolescence. Key data on adolescence. Brighton: TSA, 2003.
This is the sixth in a series of 12 articles
The first graph is adapted from Coleman and Schofield (Key data on adolescence. Brighton: Trust for the Study of Adolescence, 2003). The graph showing the sexual practices of Scottish 14 year olds is adapted from Todd J et al (Health behaviours of Scottish schoolchildren. Sexual health in the 1990s. Edinburgh: University of Edinburgh, 1999). The graph showing rates of chlamydia infection is adapted from PHLS, 2001. The graphs showing births per 1000 women, live birth rates, and adult outcomes and the box on contraception at first intercourse are adapted from the Social Exclusion Unit's Teenage Pregnancy Report (see "Further reading" box). The photograph of the condoms is published with permission from RESO/Rex and the cartoon on this page with permission from IPPF/BBC.
The ABC of adolescence is edited by Russell Viner, consultant in adolescent medicine at University College London Hospitals NHS Foundation Trust and Great Ormond Street Hospital NHS Trust (rviner@ich.ucl.ac.uk). The series will be published as a book in summer 2005.(John Tripp,Russell Viner)
Proportion of UK teenagers who first had sexual intercourse by age 16 years, 1964-98
Having sex for the first time at an early age is often associated with unsafe sex, in part through lack of knowledge, lack of access to contraception, lack of skills and self efficacy to negotiate contraception, having sex while drunk or stoned, or inadequate self efficacy to resist pressure.
About 10% of boys in the United Kingdom report that they were drunk or stoned when they first had sex, and 11% of girls report being pressurised by their partner when they first had sex. Of those under 16 years who have ever had sex, about a third to a half of both sexes report ever having had unsafe sex.
Percentages of 14 year olds in Scotland engaging in various sexual activities
Sexually transmitted infections
Considerable rises in the incidence of STIs, particularly chlamydia, have led to a major public health problem in the United Kingdom. Although rates in the under 16s have remained low, rates in 16-19 year olds and 20-24 year olds almost trebled in men and more than doubled in women during 1995 to 2001. Some studies suggest that 30-40% of sexually active teenage girls in high risk groups are infected.
Risk factors for sexually transmitted infections in adolescence
Gonorrhoea, and to a lesser extent genital herpes, has shown similar increases in incidence. The highest rates of STIs are among black Caribbean and black African young people, suggesting that cultural and socioeconomic factors play a major role in the risk of acquiring and in protection against STIs.
Rates of uncomplicated chlamydia infections in United Kingdom by age, 1995-2001
Clinical presentations of STIs in adolescents are similar to those in adults. It is important to note that chlamydia, often asymptomatic in older adolescent girls and women, usually presents with a vaginal discharge in young adolescent girls.
Teenagers assess and evaluate risk differently from adults and health professionals: they would rather reduce their risk of being excluded from the "in-group" or of looking immature than take notice of any perceived health risks
Early detection and treatment of curable STIs, such as chlamydia, can reduce the risk of further complications, such as infertility and ectopic pregnancy. With the easy availability of highly sensitive new nucleic acid amplification tests on voided urine, current UK recommendations support the opportunistic screening of all sexually active adolescent females attending general practice surgeries and genitourinary medicine and family planning clinics, regardless of whether they have symptoms. Screening young men without symptoms remains more controversial, although many suggest opportunistic screening similar to that provided for young women.
Clinical features of sexually transmitted infections in adolescents
Teenage pregnancy
The incidence of teenage pregnancy across Europe varies considerably. The United Kingdom has the highest rate in western Europe and is lower only than Bulgaria, Russia, and Ukraine in Europe as a whole. Throughout most of western Europe, teenage birth rates fell during the 1970s, '80s, and '90s, but in the United Kingdom, rates have remained high—at or above the level of the early '80s.
Live birth rate to women aged 15-19 years, 1973-96
It is important to recognise that for some young women, particularly from certain ethnic or social groups, teenage pregnancy can be a positive life choice. Rates of teenage pregnancy within marriage are high, for example, in some South Asian ethnic groups in the United Kingdom. However, for many other young women, the costs of teenage pregnancy can be very high, particularly when linked with poverty. These risks include poorer outcomes for the children of teenage mothers as well as for the mothers themselves.
Births per 1000 women aged 15-19 years, 1998
Infant mortality among babies of teenage mothers is about 60% higher than among the babies of older mothers. These infants are also more likely to have lower birth weights, have childhood accidents, and be admitted to hospital during childhood. In the longer term, the daughters of teenage mothers are more likely to become teenage mothers themselves.
Adult outcomes of teenage pregnancy compared with a reference level for women who give birth at age 23-32 and had no childhood poverty
Prevention of unwanted teenage pregnancies is a high priority in many countries. In the United Kingdom, strategies are based on the cycles of social exclusion and disadvantage that both cause and follow teenage pregnancy.
High quality evidence shows that health promotion behavioural programmes using peer educators of a similar age reduce the prevalence of sexual activity at age 16 years. Although programmes that promote abstinence have a logical appeal, no high quality studies have shown the effectiveness of such approaches, and such programmes are not seen as acceptable by many teenagers or professionals as they potentially limit young peoples' rights and autonomy.
Risk factors for teenage pregnancy
Factors known to protect young people from teenage pregnancy include higher levels of connectedness with school and family; long term, stable relationship with a partner; and strong religious beliefs
Contraception
In the United Kingdom about 75% of young people in early adolescence and 85% in mid-adolescence, of both sexes, have reported that they used an effective form of contraception the last time they had sex.
Proportion of adolescents using contraception at first intercourse
Teenagers are relatively poor users of both barrier and hormonal contraceptives. Condoms remain the contraceptive of choice of young people; over 75% reported that they used condoms at their last sexual intercourse (15% reported using the oral contraceptive, 1% injectable contraception, and 6% emergency contraception).
Condoms remain the contraceptive of choice of young people, though the combined use of condoms plus the contraceptive pill is probably the most effective option
The first time a young person has sex is one of the riskiest times for young people in the United Kingdom: half of the under 16s and a third of those aged 16-19 use no contraception the first time they have sex, as much as double the rates in other developed countries, including the United States.
Proportion of adolescents using contraception at first intercourse
Health promotion targeted at teenagers and the provision of free condoms improves contraceptive use by teenagers. The most appropriate contraceptives for most young people are likely to be condoms and the contraceptive pill. However, teenagers have a relatively high failure rate with both these methods because of "technical problems" (condom failure and irregular use of the pill). Because of this, some countries are promoting the "double Dutch" method—using condoms plus oral contraception to protect against both pregnancy and STIs.
Promoting contraception in primary care
Emergency contraception is not a substitute for a regular form of contraception and does not protect against STIs. Access to emergency contraception, however, is an important and effective preventive measure against an unwanted pregnancy. In the United Kingdom, knowledge of emergency contraception is low among young people—for example, less than half know about the 72 hour "window of opportunity." Young women aged 16 and over can obtain emergency contraception over the counter at pharmacies. However, for girls under age 16, such contraception is available only on prescription (either from doctors or, in exceptional circumstances, from approved pharmacists), thus imposing substantial limitations on its use by young teenagers at risk.
Good evidence to support current practice is limited. Increasing numbers of people believe that campaigns and educational programmes that promote postponement or temporary abstinence much more strongly than the current British programmes do might result in greater health benefits. ABC programmes (Abstinence, Be faithful, and if not, use a Condom) seem to have been remarkably successful compared with promotion of barrier contraception in some African countries, and the politically driven "abstinence-only" campaigns in the United States have coincided with falls in teenage pregnancy rates without the increases in STIs seen in the United Kingdom.
Guidance from UK Department of Health*
Evidence is increasing that, although abstinence campaigns may delay young people's first sexual intercourse, they may also increase their risk of having unprotected sex when they do begin having sex
Providing sexual health services to adolescents
Sexual health services for young people must be available in general practice in addition to specialist services. A recent study reported that over 90% of pregnant teenagers had discussed contraception with their general practitioner in the year before becoming pregnant, confirming primary care as the main provider of health services. Those at risk of pregnancy are also at risk of STIs, and it would be logical to provide both contraceptive and STI testing services together.
Desirable features of sexual health services for adolescents
Siting of services may be critical. Because of reluctance about being identified as using a sexual health service, young people may prefer to attend a general primary care clinic rather than a specialist service, even if the primary care clinic is not as youth friendly. The sex of the health professional also seems to be important, with a tendency for primary care or family planning services to be used by young women, while young men may simply buy condoms from pharmacies or vending machines.
Providing sexual health and contraceptive services in an "age appropriate" environment and manner is particularly important for adolescents, as they will simply not use services they regard as inaccessible or unfriendly. Young people report that confidentiality, a non-judgmental approach, informality, accessibility, and the ability to choose whether they see a male or female health worker are the most important factors in deciding whether to use services.
Further reading
? Rogstad KE, Ahmed-Jushuf IH, Robinson AJ. Standards for comprehensive sexual health services for young people under 25 years: UK national survey. Int J STD AIDS 2002;13: 420-4.
? Social Exclusion Unit. Teenage pregnancy report. London: Stationery Office, 1999.
? Toumbourou J, Patton GC, Sawyer S, Olsson C, Webb-Pullman J, Catalano R, et al. Evidence based health promotion. No 2. Adolescent health. Melbourne: Department of Human Services, Victoria, 2000.
? Trust for the Study of Adolescence. Key data on adolescence. Brighton: TSA, 2003.
This is the sixth in a series of 12 articles
The first graph is adapted from Coleman and Schofield (Key data on adolescence. Brighton: Trust for the Study of Adolescence, 2003). The graph showing the sexual practices of Scottish 14 year olds is adapted from Todd J et al (Health behaviours of Scottish schoolchildren. Sexual health in the 1990s. Edinburgh: University of Edinburgh, 1999). The graph showing rates of chlamydia infection is adapted from PHLS, 2001. The graphs showing births per 1000 women, live birth rates, and adult outcomes and the box on contraception at first intercourse are adapted from the Social Exclusion Unit's Teenage Pregnancy Report (see "Further reading" box). The photograph of the condoms is published with permission from RESO/Rex and the cartoon on this page with permission from IPPF/BBC.
The ABC of adolescence is edited by Russell Viner, consultant in adolescent medicine at University College London Hospitals NHS Foundation Trust and Great Ormond Street Hospital NHS Trust (rviner@ich.ucl.ac.uk). The series will be published as a book in summer 2005.(John Tripp,Russell Viner)