Teenage pregnancy rates continue to decline in England, and are now at their lowest level since 1969 (Office for National Statistics, 2017). While this is heralded as a success, under-18 conception rates in England are still the highest of similar western European countries (Whitworth et al, 2017). Importantly, teenage pregnancy rates are high in areas of deprivation (Public Health England, 2016), clustering with other public health issues such as obesity. For example, areas of high childhood obesity also have high rates of teenage parenthood—with London being the anomaly, where childhood obesity is high and teenage parenthood low (Table 1). This article outlines the risks associated with obesity in pregnant teenagers and details how midwives can support these young women with managing their weight during pregnancy.
| Area | Maternity rate per 1000 women under 18 years (2015) | Percentage of 10–11 year olds (male and female) categorised as overweight or obese (2016/17) |
|---|---|---|
| England | 10.1 | 34.2% (95% CI: 34.1–34.4) |
| North east | 16.7 | 37.3% (95% CI: 36.7–37.9) |
| North west | 11.8 | 35.2% (95% CI: 34.9–35.6) |
| Yorkshire and the Humber | 13.7 | 34.6% (95% CI: 34.2–35.0) |
| East Midlands | 11.4 | 33.5% (95% CI: 33.1–33.9) |
| West Midlands | 11.6 | 37.1% (95% CI: 36.7–37.5) |
| East of England | 9.4 | 31.1% (95% CI: 31.1–31.9) |
| London | 7.0 | 38.6% (95% CI: 38.2–38.9) |
| South east | 7.9 | 30.6% (95% CI: 30.2–30.9) |
| South west | 7.7 | 30.1% (95% CI: 29.7–30.5) |
Risks associated with maternal obesity and gestational weight gain
In 2016, 22 645 babies were born to mothers under the age of 20 in England and Wales (Office for National Statistics, 2017). Similar to adult pregnant women, maternal obesity is common in pregnant teenagers. A UK study of 2000 teenagers found about 20% of pregnant teenagers between 14-18 years to be overweight and 10% categorised as obese (Baker et al, 2009) in early pregnancy, based on age-adjusted classifications for teenage body mass index (BMI). While it has been suggested that maternal obesity may protect against preterm delivery in these young women (Baker and Haeri, 2014), it is also associated with risks such as pre-eclampsia, caesarean birth, and having a baby who is small for gestational age (Kansu-Celik et al, 2017).
In addition to the risks associated with maternal obesity, focus also needs to be on the weight gained during pregnancy. A recent review found that young women may gain between 14 and 17 kg (Marvin-Dowle et al, 2016) during pregnancy, which is more than recommended by international guidelines (Institute of Medicine, 2009). Little research is available on teenagers' views regarding their weight gain in pregnancy. In one small qualitative study with pregnant teenagers in the US, none of the participants reported concerns about excessive weight gain (Wise, 2015). This is similar to research findings with adult women in the UK (Olander et al, 2011) and is likely due to the limited information pregnant teenagers receive on gestational weight gain. A recent UK study found that less than one in five young women reported receiving information on gestational weight gain (Soltani et al, 2017). This is in stark contrast to information about ‘foods to avoid’, which three-quarters of women reported receiving. To support pregnant teenagers to gain a healthy weight in pregnancy, focus needs to be on weight-related behaviours and how to support healthy eating, physical activity and reducing sedentary behaviour.
Healthy eating
Pregnant teenagers have specific dietary requirements to support both their own continued growth and development as well as that of their baby (Soltani et al, 2017). Some authors have argued that there is a competition for nutrients between the mother and fetus (Moran, 2007). This is concerning as studies have also found that pregnant teenagers often have a poor diet and a nutrient intake that is below recommended values for energy, iron, folate, calcium and magnesium, among others (Moran, 2007).
The research literature is mixed regarding whether pregnant teenagers change their dietary behaviour when they become pregnant. A UK study found that young women reported making positive changes to their diet, but that some of these changes involved avoiding food groups unnecessarily (Soltani et al, 2017). However, other research from the US has suggested that very few pregnant teenagers make changes to their diet when becoming pregnant (Whisner et al, 2016). These findings mirror a review that identified inconsistent changes in the diets of adult women during pregnancy (Hillier and Olander, 2017). Such mixed findings have implications for service development and intervention, as it is uncertain which dietary changes teenagers may make spontaneously, and which may require added input from health professionals.
Pregnant teenagers report a number of barriers to eating healthily, including a lack of money, access to food, and personal relationships not supporting a healthy diet (Whisner et al, 2016). In this study, teenagers (defined as being aged 14–18 years old) also reported relying on others to buy or cook their food, meaning what they ate may have been outside their control (Whisner et al, 2016). A study by Wise (2015) found that misconceptions regarding diet during pregnancy persisted, for example that taking vitamins could justify eating unhealthy food. Furthermore, the value of prenatal vitamins was found to be overestimated by these pregnant 16–19 year olds, who felt that vitamin supplements replaced the vitamins and minerals found naturally in healthy foods. Such misapprehensions suggest that women need education regarding maternal diet and fetal development during pregnancy (Wise, 2015).
Physical activity and sedentary behaviour
While healthy eating has been studied to some degree in the pregnant teenage population, less research has been undertaken concerning physical activity and sedentary behaviour. A small survey from the US suggests that pregnant teenagers would be more physically active if they had an exercise partner or were members of a gym (Wise and Arcamone, 2011). Keeping physically active during pregnancy is associated with improved mental wellbeing (Haakstad et al, 2016). Given the high rates of mental health problems in pregnant teenagers, emphasising that physical activity might improve subjective sense of wellbeing may be important (Dinwiddie et al, 2018). Guidelines from the National Institute for Health and Care Excellence (NICE) (2010) apply to teenagers and recommend at least 30 minutes per day of moderate intensity activity, which is characterised as activity that leads to faster breathing, increased heart rate and feeling warmer, such as walking at 3–4 mph. If teenagers find this target difficult, they should be supported to start small and then work up to this physical activity level. In addition, teenagers should be supported to reduce sedentary activities, which includes sitting for long periods of time (NICE, 2010).
Supporting teenagers to eat healthily and keep active during pregnancy
The importance of healthy eating has been acknowledged by young pregnant women (Whisner et al, 2016) and acting as a positive role model for their child may be a motivating influence for these women to eat healthily (Wise, 2015). This suggests an opportunity for behaviour change—although given the complexity of weight and food related behaviours, solely having the motivation to change is rarely enough to succeed (Olander et al, 2016). Rather, some behaviour change theory suggests that physical and psychological capability (i.e. the willpower to act), and physical and social opportunity (i.e. an environment that allows and encourages action) are needed to change behaviour (Michie et al, 2011). In other words, to encourage healthy eating, pregnant teenagers need to be able to afford healthy ingredients, understand the recipes and have the skills and appliances to cook the food, as well as the social support to do this. Social support in particular seems to be an important factor in influencing pregnant women's decisions regarding healthy eating and physical activity (Atkinson et al, 2016a).
There are few interventions to target pregnant teenagers' weight-management behaviours (i.e. healthy eating and physical activity) which is in contrast to the many interventions developed for adult women (Thangaratinam et al, 2012). Importantly, young women may have different motivators and barriers to engage in healthy weight-related behaviours during pregnancy (Chang et al, 2017); therefore it should not be assumed that what works for adult women will necessarily work for teenagers. For example, factors such as a teenager's home environment and education will affect her eating habits (Moran, 2007) and levels of physical activity. Furthermore, pregnant teenagers have been found to be more likely to access maternity care late (Barber et al, 2017)—research that needs to be considered when developing interventions or service pathways to ensure that they can be adapted or tailored towards women joining at different time points. Below are some more suggestions, based on the academic literature, on what to consider when supporting pregnant teenagers with weight-related behaviours in pregnancy.
Service content
Based on interviews and surveys with pregnant teenagers, research suggests that these women want practical support on how to make healthier choices from menus at fast food restaurants (Wise, 2015). This could include suggestions such as choosing a burger without a bun, opting for a small portion of chips, or having sandwiches on brown or wholemeal bread without mayonnaise (First Steps Nutrition Trust, 2013). Young women also want recipe books outlining healthy meals and snacks (Soltani et al, 2017). For service development it is also helpful to identify what is of less interest to women; research has suggested that this includes learning about which food sources provide which nutrients (Wise, 2015) or providing a phone helpline (Soltani et al, 2017).
In terms of physical activity, research from the adult pregnant population suggests that women want to know which activities are safe and appropriate in pregnancy (Leiferman et al, 2011), and to receive help regarding tailored advice and goal-setting (Atkinson et al, 2016b). It is likely that pregnant teenagers will benefit from this type of support in addition to the physical opportunity and social support mentioned earlier.
Service delivery
Research suggests that health professionals, such as midwives (and, later in the pathway, health visitors) may be appropriate deliverers of support for healthy eating and physical activity. Health professionals such as midwives and family nurses are consistently reported to be an important source of information for this population of women (Soltani et al, 2017). Other sources of information include older relatives such as sisters, mothers and grandmothers (Wise, 2015; Whisner et al, 2016). While not delivering support for healthy eating and physical activity directly, others who should be aware of services and able to refer include social workers and teachers (Macleod and Weaver, 2003). Indeed, there are also suggestions that interventions should be multidisciplinary to adequately support the complex psychosocial needs of these young women (Nielsen et al, 2006), and could include dieticians, exercise professionals and weight management specialists.
In delivering information and support, professionals also need to be sensitive to the way in which pregnant teenagers report feeling that their bodies are scrutinised by others, and how this public monitoring can be upsetting and distressing (Neiterman and Fox, 2017). The physical changes that both puberty and pregnancy bring may affect body image, which is a vital part of self-concept and self-esteem during adolescence (Kostanski and Gullone, 1998; Zaltzman et al, 2015) and needs to be considered in services targeting weight.
There are a number of suggestions from the academic literature on how to engage teenage parents in nutrition education programmes. In a study by Wise (2015) young women made suggestions, which included offering incentives such as baby-related items, informing women of the topics before they attend any sessions, delivering information by their peers or in an online/video format, and providing practical cooking advice. Young women were less interested in shopping tours where healthy eating was discussed, as they were rarely the primary shopper (Wise, 2015). Online resources have also been identified as mechanisms to deliver information (Soltani et al, 2017). Importantly, services must consider the pregnant teenager's ability to follow advice offered, bearing in mind her social circumstances and broader determinants to health (McCall et al, 2015).
Conclusion
In summary, maintaining a healthy weight and good nutrition during pregnancy is a concern in the teenage population. The support that pregnant teenagers want is similar to what adult women want during pregnancy, but there are factors that must be taken into consideration, such as teenagers' continued growth and changing bodies, as well as their possible lack of control over shopping for food or cooking meals. Delivery and content of support therefore needs to be different from adult women's weight-related services in pregnancy and should focus on the overall wellbeing of the teenage woman. Given the reduction in teenage pregnancy rates and the further emphasis on reducing teenage pregnancy, it is imperative that a structure of multidisciplinary support remains in place for these mothers, whose own health outcomes are crucial to improving those of their children.