Abstract
Teenage pregnancy has major implications for the mother and child, their wider family, and at a societal and population level. Although teenage pregnancy rates have fallen substantially over the last 30 years, they remain higher in the UK relative to other countries in Western Europe, and a high proportion of teenage pregnancies are unplanned. Teenage pregnancy is associated with major health inequalities, including lower maternal socioeconomic status and education. Furthermore, there is a lack of guidance to inform the antenatal management of teenage mothers to optimize both short- and long-term outcomes for mother and child. This review article outlines the latest trends in teenage pregnancy in the UK, the risks of teenage pregnancy for the mother, fetus and child, and presents proposed antenatal management strategies to optimize outcomes of teenage pregnancies.
Trends in teenage pregnancy
The teenage pregnancy rate, defined as the number of conceptions per 1000 women under 20 years of age, has steadily declined over the last two decades, both in the UK and on an international scale. In Scotland, England and Wales, the teenage pregnancy rate fell to its lowest reported level in 2021, at 23.2 conceptions in Scotland and 26.1 conceptions in England and Wales per 1000 women aged 15–19 years of age. In the UK, the teenage pregnancy rate has reduced by over 55% since 1994, and there was an accelerated decline in teenage conceptions across Scotland, England and Wales from 2007 onwards. In parallel with the reduced rates of teenage conceptions, the proportion of conceptions and births in women aged 35 years and above has risen across the UK. In 2021, the proportion of births in women under 20 years comprised only 3% of all births, compared to 9% of all births in 1990, while the percentage of women giving birth at 35 years and above reached its highest record rate in 2021 at 23%, having risen substantially from 7% in 1990. The proportion of teenage pregnancies which occur within younger age groups has also reduced over time in the UK. In 2021, of all teenage conceptions in Scotland, 33% occurred in women under 18 years, and 6% of women were under 16 years of age, compared to 1994, when 44% of teenage pregnancies occurred in under-18s and 9% in under-16s. Figure 1 from Public Health Scotland shows trends in the teenage pregnancy rate in Scotland by age of conception, since reporting began in 1994.
Globally, the adolescent birth rate (in women aged 15–19 years of age) has reduced from 64.5 per 1000 women in 2000 to 41.3 per 1000 women in 2023, but major variation exists between countries. The highest rates of teenage pregnancies are consistently observed in West and Central Africa, at 105.1 live births per 1000 women aged 15–19 years of age in 2022, compared to 7.6 per 1000 women aged 15–19 years of age in Western Europe.
A high proportion of teenage pregnancies are unplanned, and result in termination of pregnancy. As the overall rate of teenage pregnancy in the UK has reduced, the proportion of teenage pregnancies which result in termination of pregnancy has increased over the last three decades. Over half of teenage pregnancies in 2021 (53% in Scotland and 52% in England and Wales) resulted in termination, significantly increased from one third (33%) of teenage conceptions in Scotland in 1994. This contrasts with the overall rate of termination of pregnancy across all age ranges, which was 26.5% in 2021 across England and Wales. Women who conceive under 16 years old are the most likely terminate their pregnancy. In 2021, 60% of conceptions in women under 16 years of age in England and Wales resulted in termination of pregnancy, and in Scotland, almost two thirds (65%) of conceptions in women under 16 years old culminated in termination. In low and middle income countries in 2019, half of all pregnancies in women aged 15–19 years of age were unplanned, 55% of which resulted in termination of pregnancy, which is frequently unsafe in these settings.
The overall reduction in teenage pregnancies observed in the UK over the last two decades has been attributed, at least in part, to the implementation of various public health strategies. In 1999, the UK Government launched the 10-year “Teenage Pregnancy Strategy” in England, which was an intersectoral programme that aimed to halve the conception rate in women under 18 years of age by 2010, and to mitigate social exclusion in teenage parents. The Teenage Pregnancy Strategy comprised several components, including the provision of high quality sex education in schools, improved sexual health services for young people, joint action to ensure local and national coordination of statutory and voluntary agencies, and better support for teenage parents to facilitate completion of education and to secure employment. Financial resources were invested differentially based on the level of socioeconomic deprivation in different areas of the country. Although the programme did not meet its target, the rate of conception in women under 18 years of age had halved in England by 2014, and the most substantial reductions were observed in more deprived areas. In 2016, the Scottish Government implemented a similar initiative, the “Pregnancy and Parenthood in Young People (PPYP) Strategy”, to decrease the cycle of deprivation associated with teenage pregnancy while improving support for young parents; a progress report in 2019 demonstrated that the PPYP Strategy had reduced rates of teenage pregnancy, particularly in more deprived areas, and reduced rates of termination of pregnancy in women under 20 years of age. In a 2016 Cochrane systematic review, Oringanje et al. examined 52 randomized controlled trials on prevention strategies for teenage pregnancy, and concluded that a multifaceted approach, combining education and contraception promotion interventions, significantly reduced the risk of unintended pregnancy amongst adolescents (four trials, relative risk 0.66, 95% confidence intervals 0.50–0.87). Notably, the majority of trials included were conducted in high-income settings, and the review recommended that further research was needed to explore the effectiveness of teenage prevention strategies in low-income countries.
In addition to government initiatives, other factors are considered to have driven the declining UK teenage conception rate over the last three decades, although the relative contribution of each factor is unclear. The expansion in internet access and smartphone use among young people may have contributed to a gradual reduction in “risk behaviours” during adolescence, including sexual activity; potential mechanisms underpinning these associations may include increased access to information on contraception, and increased employment opportunities. The British Pregnancy Association Service (BPAS) conducted qualitative and quantitative research into teenage lifestyles and behaviours, which demonstrated that changing patterns of socializing amongst teenagers, who increasingly interact online rather than in-person, have decreased traditional teenage risk-taking behaviours, including sexual activity. BPAS also reported other important factors contributing to the declining teenage pregnancy rates, including the substantial reduction in alcohol consumption amongst teenagers since the early 2000s, which correlated with reduced teenage sexual activity, as well as largely negative attitudes towards teenage pregnancy and higher educational aspirations among the current generation of young people, compared to previous teenage populations.
Using interrupted time series analyses, Baxter et al. demonstrated that the reduction in teenage pregnancies in England from 1998 to 2016 resembled trends observed in Scotland, Wales, and 15 other European and high-income English-speaking countries, despite the absence of the UK Teenage Pregnancy Strategy, or equivalent, nationally-funded, coordinated programmes targeting teenage pregnancy prevention in these countries during that time. The authors postulated that the Teenage Pregnancy Strategy had “little if any impact” on teenage pregnancy rates, and instead suggested that declining rates could be attributed to other factors spanning several countries, such as economic changes, improved contraceptive technologies, and greater access to education for young women.
While there has been an overall reduction in rates of teenage pregnancy, the UK continues to have one of the highest rates of teenage conceptions in Western Europe. Importantly, teenage pregnancy is strongly associated with socioeconomic deprivation, which is associated with considerable obstetric risk: in 2023, Public Health Scotland reported that teenagers living in the most deprived areas have pregnancy rates over four-fold higher than those in the least deprived areas. A clear understanding of risks specific to teenage pregnancy, and how best to address and manage these risks, is essential to improve outcomes for teenage mothers and their children.
Risks and adverse outcomes associated with teenage pregnancy
The increased risk of adverse maternal and fetal outcomes observed in teenage pregnancy reflects a complex interplay of several biological and psychosocial factors, which may include social deprivation, maternal social stigma and isolation, poor engagement with antenatal services, suboptimal nutritional status and physiological “immaturity”. Adverse outcomes associated with teenage pregnancy can be broadly classified into short-term obstetric and perinatal risks, and long-term risks to the parents and the child, as outlined in Table 1 . Several socioeconomic risk factors frequently co-exist in teenage pregnancy, and resultingly, it is difficult to elucidate the relative contributions of individual risks. Compared to pregnant mothers aged 20–35 years, teenage mothers are more likely to live in socially deprived areas, are three times more likely to smoke during pregnancy, and have higher rates of substance and alcohol misuse; complications associated with these socioeconomic risk factors are frequently observed in teenage pregnancies, including preterm birth, low birth weight and Sudden Infant Death Syndrome. Teenage women also have the poorest diets in the UK compared to other population groups, which further compounds these risks. It has also been postulated that young women who are still growing themselves may “compete” with the fetus for nutrients, resulting in impaired fetal growth and low birth weight.
| Obstetric risks | Long-term risks | |
|---|---|---|
| Parental | Infant/child | |
| Preterm birth | Social exclusion & stigma | Infant mortality, including Sudden Infant Death Syndrome |
| Pre-eclampsia | Physical illnesses including premature death | Increased hospitalization for gastroenteritis or accidental injury |
| Fetal growth restriction & low birth weight | Poorer mental health including postnatal depression and suicide | Neurodevelopmental delay |
| Stillbirth | Unemployment | Behavioural, emotional & hyperactivity disorders |
| Neonatal death | Failure to complete education | Increased likelihood of teenage pregnancy |
| Urinary tract infection | Relationship breakdown | Child poverty |
| Endometritis | Future unplanned pregnancies | |
| Anaemia | ||
| Complications from sexually transmitted infections | ||
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