The UK is reported to have the highest rate of teenage pregnancies (girls aged 15–17 years) in Europe, being eight times that in The Netherlands, five times that in France and three times that in Germany.1 In addition to the potential health effects for the mother and the baby, the socio-economic impact of teenage pregnancy and its effect of widening health and social inequalities have led the UK government to set targets to halve the under-18 conception rate in England by 2010 from the 1998 rate of 46.6 per 1000.2 3 As the deadline for this target approaches, local strategies led by local authorities and primary care trusts are now in place with targets for reductions of between 40% and 60%.4

Teenage mothers and their babies are at increased risk of poor health outcomes, but there is debate as to whether young maternal age is intrinsically a risk factor for adverse health outcomes or if the increased risk is attributable to the socio-economic circumstances leading to and following pregnancy in this group.5^–7 Some teenage pregnancies are planned. It has been suggested that concern over teenage pregnancies is misplaced as teenagers can be physically and mentally better suited for pregnancy than older couples.8 9 However, for young girls who live in deprived areas, pregnancy can increase the risk of social exclusion and socio-economic disadvantage, leading to poorer health and well-being.2 7

In this review, we examine the epidemiology of teenage pregnancy in the UK and consider the evidence for its impact on the health and well-being of the mother, the baby, the father and society.

METHODS

We searched the published literature using the search strategy and databases shown in box 1. Two authors (SP and HB) independently screened the titles and abstracts to identify articles that were relevant for this review. We categorised articles according to the outcomes that were reported for mothers, babies, fathers and society. Data on the epidemiology of teenage pregnancy were obtained from the Office for National Statistics website for England and Wales,10 the Information Services Division website for Scotland,11 the Department of Health, Social Services and Public Safety in Northern Ireland12 and the Eurostat website13 for comparative European data.

Epidemiology of teenage pregnancy

Within Europe teenage birth rates vary widely from 1.5 per 1000 females aged 15–17 years in Switzerland to 16.6 in the UK in 1998.1 13 Rates in The Netherlands, France and Germany were 2.2, 3.4 and 5.3 per 1000, respectively.1 13

The Office for National Statistics (ONS) in the UK defines conception as pregnancies resulting in live births, stillbirths or legal terminations.14 Conception rates are available from the ONS for the under-20 (15–19 years) and under-18 (15–17 years) age groups. In this paper we discuss conception rates for the under-18 age group, as this is the government target group. In England and Wales, the under-18 conception rate per 1000 females decreased from 47.1 in 1998 to 42.4 in 2003 and 41.4 in 2005.15 In Scotland these rates were 44.9 in 1998, 40.3 in 2003 and 41.5 in 2005.11 Data on conceptions are not available for Northern Ireland; however, the fertility rate in the under-20 age group decreased from 27.8 per 1000 in 1998 to 21.7 in 2005.12

Although overall conception rates are similar between the UK home nations, there is large variation between regions, and between local authority areas within regions. Provisional data for 2006 from ONS suggest that under-18 conception rates in England range from 48.3 per 1000 in the North East to 32.9 per 1000 in the South East and South West.16 Twenty five per cent of unitary authorities in England had rates below 33 per 1000 and a further 25% had rates above 52 per 1000. The overall rate in Wales was 44.8 per 1000 females, ranging from 58.9 in the highest to 31.8 in the lowest local authority areas.16 Similar variation has been observed in Scotland, partially attributed to variation in population and socio-economic characteristics within the country.2 17

The average age at first birth in the UK has increased from 26 in 1996 to 27 in 2006.18 However, these data are based only on married women and therefore may not be accurate as teenage girls are unlikely to be married when they become pregnant. In 2006, 93% of births to teenagers occurred outside of marriage, an increase from 88% in 1986.18

Approximately 7% of live births in England and Wales are to females aged less than 20 years, although this varies according to the mother’s country of birth.14 Nine per cent of Bangladeshi mothers were under 20, compared with less than 3% of mothers born in India, East Africa, Australia, Canada or New Zealand.14 However, this may be partly attributable to differences in the age structures of these populations with more recent immigration from Bangladesh compared to other countries.14 Early marriage and childbearing is traditional in some populations and so the social circumstances and hence outcomes associated with younger childbirth may be different for these populations.

Teenage mothers in the UK are reported to have a lower socio-economic background, more siblings and parents who show less interest in their education or live in a lone parent family.19^–22 The risk of becoming a mother before the age of 20 is nearly one in three for teenagers from vulnerable backgrounds. Having a mother with no qualifications, low educational attainment or a mother who herself had a teenage pregnancy is associated with increased risk of teenage pregnancy.23 24 Compared with girls in social class 1, the risk of becoming a teenage mother is nearly ten times higher for girls whose family is in social class V.14 25

DOES THE MOTHER SUFFER?

In this section we consider the impact of teenage pregnancy on the health and well-being of the mother, with effects ranging from obstetric complications during pregnancy to psychosocial and mental health morbidity in the longer term. The majority of studies investigating the effects of teenage pregnancy compare a young 16–19-year-old age group with an older group. This can make comparisons difficult as it does not allow for differences in physical or psychological maturity over the range of the teenage years.

The evidence for obstetric complications associated with teenage pregnancy is shown in table 1.26^–30 Three studies have reported that teenagers were approximately twice as likely to be anaemic (haemoglobin <10.5 g/dl).26^–28 The most common cause of this anaemia was iron deficiency attributed to poor nutrition.26 27 Although severe anaemia during pregnancy is associated with poor health outcomes for the mother, the significance of moderate anaemia is less clear.31

While there is some evidence for increased risk of pregnancy induced hypertension (relative risk (RR) 1.7, 95% CI 1.3 to 2.4) for pregnant nulliparous teenagers compared with adults,27 studies that have investigated the incidence of pre-eclampsia or proteinuric disorders among nulliparous teenagers compared with adults did not find any difference between the two groups after adjusting for confounding factors such as cigarette smoking,26 29 supporting the view that teenage pregnancy complications can be prevented with regular ante- and postnatal care.32

Although teenagers are 46% less likely to have an emergency or elective caesarean section compared with women aged 25–29 years,30 they are at higher risk of instrumental deliveries. Teenagers under 16 are twice as likely to have forceps delivery compared with women aged 20–24 years.27 The reason for the higher rates of instrumental delivery is not clear, although it is postulated to be due to the physical immaturity of the younger mother33 or “fright and lack of cooperation” in the second stage of labour.27 A systematic review has shown that social support interventions (such as home visits) for pregnant teenagers are effective in reducing caesarean section rates in this group.34

In developing countries, complications from pregnancy and childbirth are the leading cause of death among teenagers.35 In the UK, maternal mortality is rare (14 per 100 000 maternities)36 and is even lower in the under twenties, at 9.9 per 100 000 maternities.36 In the most deprived areas of England, maternal mortality is 46% higher than in the least deprived areas, and unemployment is associated with a sevenfold increased risk of maternal death (RR 7.4, 95% CI 5.6 to 9.0).36 Although young maternal age is not itself an identified risk factor for maternal mortality in the UK, some of the vulnerable circumstances that are risk factors for mortality, such as socio-economic disadvantage, are also risk factors for and the consequences of teenage pregnancy.7 36

The longer term health implications for the teenage mother were assessed in a Swedish population based cohort study using record linkage of census data with at least 30 years’ follow-up.37 Compared with mothers aged 20–24 years at first birth, there was a 70% increase in the risk of premature death for mothers aged 17 years or under at first birth, and a 50% increase for those aged 18–19 years.37 The major causes of death associated with a previous teenage birth were cervical cancer, ischaemic heart disease, suicide, and death following violence, assault and homicide. These increased risks are related to health damaging lifestyles, poor psychosocial health or a violent environment, all factors known to be closely associated with poverty and deprivation.19 Although these increased risks remained statistically significant after adjustment for socio-economic status, they are less likely to be due to younger age at childbirth than the effect of residual confounding from individual lifestyle variables such as smoking status, alcohol use and obesity that were not measured in this study.

In the UK, research on mothers of twins showed that compared with adult mothers, teenage mothers experienced more deprivation and more mental health difficulties and had lower levels of educational attainment, and more emotional and behavioural problems.7 Teenage mothers are three times more likely to be living in poverty compared with mothers in their thirties,39 and are less likely to complete their education and training.7 They therefore face restricted job opportunities, potentially reinforcing the cycle of deprivation and teenage pregnancy.7 24 38

However, it is recognised that some mothers who have an early childbirth have better psychosocial outcomes than others.7 Evidence from the 1970 British Cohort Study showed that some of the health disadvantage suffered by teenage mothers is explained by their parental background and childhood characteristics.39 A large retrospective cohort study in the USA found that teenage mothers who suffered adverse childhood experiences had increased risk of psychosocial outcomes (high stress, uncontrollable anger and serious or disturbing problems with their families, jobs and finances) compared with those who did not have adverse childhood experiences.40 The authors suggest that the psychosocial consequences for the mother are a result of the childhood experiences that precede the teenage pregnancy, rather than the pregnancy and childbirth itself. These findings may however be subject to recall bias, which is a limitation of retrospective cohort studies.

A systematic review of the effectiveness of preventive psychosocial and psychological interventions compared with usual ante-partum, intra-partum or post-partum care to reduce the risk of post-partum depression found that intensive professionally based post-partum support may be helpful, particularly if this is targeted at an at-risk group which includes teenage mothers.41 Evidence from randomised controlled trials in the USA42 showed that the home visiting interventions that form the basis of the Nurse-Family Partnership programme43 have positive effects for mothers, such as fewer and more widely spaced pregnancies and better financial status. The Nurse-Family Partnership programme was piloted in 10 sites in England, and the evaluation reported high enrolment of women under 20, a 17% relative reduction in smoking during pregnancy and high rates of initiating breast feeding.43

THE BABY

Teenage pregnancy is a risk factor for adverse baby outcomes such as pre-term delivery, low birth weight, small for gestational age, and neonatal and infant mortality (table 2).28 29 44^–48 However, the socio-economic and behavioural factors (tobacco, alcohol or recreational drug use, poor nutrition and poor antenatal care attendance) associated with teenage pregnancy are also risk factors for these adverse baby outcomes.

A study of births to women aged under 25 years of age in the USA found that after adjustment for confounding factors (state of birth, maternal race, marital status, tobacco smoking and alcohol use during pregnancy, and prenatal care status), teenage pregnancy was independently associated with the increased risks of very pre-term delivery, pre-term delivery, very low birth weight, low birth weight, small for gestational age and neonatal mortality.44 These findings did not change when the analysis was restricted to white married mothers with age-appropriate education, who received adequate prenatal care and did not smoke or drink during pregnancy. The authors conclude that their findings challenge the argument that many of the adverse outcomes associated with teenage pregnancy are attributable to low socio-economic status.44 However, this study did not adequately control for employment status or occupation, neither did the study measure the effect of using recreational drugs or psychological and emotional stress during pregnancy as potential confounders. These factors have been identified in other studies as risk factors for pre-term birth.49^–51

Low birth weight is an important determinant of childhood mortality, especially in developing countries.34 Young maternal age is associated with increased risk of low birth weight,29 44 45 47 which is generally used by clinicians as a proxy measure for intra-uterine growth restriction (IUGR). The social aetiology of IUGR includes psychosocial stress which can result from social isolation, homelessness and violence.51 52 Low birth weight, small for gestational age and prematurity are important because of their associated medical complications and poor neonatal survival.47

One limitation of studies on teenage mothers is the lack of information on whether or not pregnancy is wanted, as this could affect behaviour during the pregnancy and attitudes towards antenatal care.25 Estimates from the Millennium Cohort Study suggest that only 15% of teenage mothers plan their pregnancy.53 Teenagers are five times more likely to smoke throughout the pregnancy compared with older mothers.54 In addition, the prevalence of poor diet, alcohol and drug misuse is higher among younger age groups in the population and can impact negatively on the pregnancy, particularly in unplanned circumstances.55

Babies born to teenage mothers are at increased risk of maltreatment or harm, and have higher rates of illness, accidents and injuries as well as cognitive, behavioural and emotional complications.7 39 However, higher levels of behavioural problems in children born to teenage mothers have been attributed mostly to the mother’s mental state rather than the young age of the mother.39 The association between younger age at childbirth and poorer cognitive and behavioural outcomes in children is unlikely to be causal, as developmental outcomes in children have been shown to be associated with maternal age at first birth rather than at the given child’s birth.6 Analysis of data from sisters has shown that the disadvantage of children born to younger mothers is greatly reduced after controlling for maternal family background.6 Further evidence suggests that the difficulties and disadvantages associated with early first childbirth are long-lasting with poorer behavioural and emotional outcomes for children born to mothers who were under 20 years of age at first childbirth compared with those who were in their twenties.7 Recent developments in our understanding of child development have highlighted the importance of early environments, nurturing relationships and the health and well-being of the child’s parents,56 forming the basis for community based interventions such as Head Start in the USA,57 SureStart58 and more recently the Nurse-Family Partnership programme42 43 in the UK. A meta-analysis of home visiting programmes for families with young children has shown better child development outcomes associated with this intervention.59

Other interventions include comprehensive social and medical care using antenatal clinics specific for teenagers, which has been shown to reduce the pre-term birth rate among females under 18 years of age in a randomised controlled trial.60 However, there is no evidence that provision of social support on its own to pregnant teenagers, for example with additional home visits, although useful for reducing caesarean section rates, reduces the incidence of pre-term birth or low birth weight babies in teenagers.34

THE FATHER

Studies on teenage pregnancies tend to focus on the mother and baby. The limited research available indicates that young fathers have low socio-economic status backgrounds, with low levels of education and low earning potential.39 Men who become fathers in their teens or early twenties are twice as likely to be unemployed, receive benefits and require social housing, after allowing for the poorer backgrounds and lower educational ability that predisposed to young fatherhood.39

A qualitative study of low-income young fathers suggests that young fathers use their own fathers as a benchmark of what to do and what not to do, and that those who have grown up without a father want to do things differently.61 62 The inability to adequately provide financial support can be damaging to a young father’s confidence and sense of self, while accepting parenting responsibilities and being significantly involved with their child is associated with positive benefits for father and child.61 63 Higher levels of paternal engagement have positive effects on child development with reported lower levels of delinquency, higher IQ scores and fewer behavioural problems.63

A UK based study interviewed young first-time fathers and found that many of them felt excluded from being involved in the pregnancy by healthcare professionals who, in turn, reported knowing little about the fathers.64

Interventions such as nurse home visiting (Nurse-Family Partnership programme) are also associated with positive outcomes such as higher levels of paternal engagement.42 43 Improving parent–child interaction is important, particularly as evidence suggests that this has a significant influence on the child’s development.65 The impact of fatherhood during the teenage years on longer term health and well-being is poorly studied and warrants further exploration.

FROM A SOCIETAL PERSPECTIVE

Teenage pregnancy is perceived by the UK government to be a social and economic problem.2 In some countries (such as the UK and the USA) the increase in teenage birth rates is partially attributed to society moving away from traditional family values, described by Kmietowicz as entering a “socio-sexual transformation”.66 Countries that have prepared for an increasingly sexualised society and ensure that their young are well informed (eg, The Netherlands) have lower teenage pregnancy rates.66

Moffit et al argued that much of the evidence of the effects of teenage pregnancy has been from UK cohorts from 1946 and 1958, therefore referring to a population that were teenagers in the 1960s and 1970s, at a time when early marriage and childbearing was the norm. As society has changed over time, women have delayed childbirth; women who have early childbirth risk disruption of their education and hence are at risk of disadvantage when compared with their cohort peers, many of whom would have continued on to post-secondary education. Therefore, childbirth in the teenage years has become even more “deviant”.7 Moffit’s work on a cohort of twins shows that mothers who had their first child before the age of 20 in the late 1980s and early 1990s have continued to experience similar difficulties as earlier cohorts, with more socio-economic deprivation, less human social capital and more mental health problems than women who gave birth in their twenties.7 Children of women who chose to postpone motherhood in order to complete education and compete in the work place are associated with positive growth and development. However, the cohort of young “NEET” (not in education, employment or training) mothers have a wide range of difficulties related to their social background, which can have long term implications for their children,7 and hence society in the future. Furthermore, evidence suggests that children with absent fathers in early childhood are more likely to be sexually active at a younger age and have a teenage pregnancy, therefore perpetuating the cycle.67 This can inevitably result in widening the inequalities gap. Investment in programmes such as SureStart59 and the Nurse-Family Partnership43 aim to provide early interventions to reduce future inequalities by improving behaviour and language development in children from disadvantaged backgrounds, targeting young mothers in deprived areas.

It is estimated that the cost to the NHS alone of pregnancy among under 18 year olds was over £63 million per year in 2002.25 The national policy target is to halve teenage pregnancy rates by 2010, but data from the Social Exclusion Unit show that despite the slow and steady decline in conception rates for under 18 year olds (15–17 years), the 2010 target will not be met.3 Further examination of these data has shown that the majority of the observed decrease is attributable to reductions in less deprived areas.3 In areas of higher deprivation, there has been little change, resulting in renewed efforts and interventions to meet this target, and a shift from national to more localised initiatives.3

CONCLUSION

There has been little change in the teenage pregnancy rate over the last decade in the UK and rates are still considerably higher than those in other European countries. The aim of this review was to consider who suffers from the consequences of teenage pregnancy. Pregnancy and childbirth during the teenage years are associated with increased risk of poorer health and well-being for both the mother and the baby, reflecting more the socio-economic factors that precede and follow early pregnancy than the biological effects of young maternal age. There is little evidence concerning the impact of teenage fatherhood on health, and future studies should investigate this. The impact on society is a perpetuation of the widening gap in health and social inequalities. Government initiatives, interventions and support services aimed at young mothers should continue to be targeted at vulnerable groups of society with specific socio-economic and demographic characteristics, as the available evidence suggests that these groups and their children are at highest risk of poor health and social exclusion. Further research should examine the longer term morbidity for teenage mothers, young fathers and their children, to gain a better understanding of how much of this morbidity is attributable to socio-economic characteristics and the pathways that mediate this.