Approximately 4% and 7% of UK consumers identify as vegans and vegetarians, respectively (Wunsch, 2024). The Food Standards Agency (2020) states that ‘those belonging to Generation Z [typically 16–25-year-olds], alongside Millennials [typically born between 1981 and 1996], are among the most likely to eat no meat or to be reducing their consumption of meat’.
What can be inferred about the quality of the food eaten by vegetarians/vegans, some of whom are pregnant or contemplating pregnancy? Analysing data from the UK national survey (2008/2019), Torquato et al (2024) found that ‘ultra-processed foods contributed more than half of the energy consumed by the UK's vegetarian population, with emphasis on packaged breads, meat-free ready-to-eat dishes and sweets and desserts'. This is interesting in the context of a Finnish retrospective case-control study of 150 women on a vegetarian diet and 300 omnivores, where Reijonen et al (2024) found that ‘gestational diabetes was more common in the vegetarian group’.
How can vegetarian or vegan diets affect pregnancy outcomes? Reijonen et al (2024) reported that ‘a vegetarian diet may be considered safe during pregnancy. It was not associated with an increased risk of pregnancy- or neonatal complications’. However, in a systematic review and meta-analysis, Papadopoulou et al (2025) reported that ‘strict vegetarian diets during pregnancy are associated with an increased risk of small-for-gestational-age infants and lower birth weights. To mitigate these risks, specific dietary guidelines emphasising adequate intake of critical nutrients such as vitamin B12, iron, omega-3 fatty acids and iodine should be developed’.
Jahan-Mahan et al (2024) acknowledged that ‘a vegetarian diet during preconception can impact offspring health, offering benefits like antioxidants and phytochemicals that support fetal development and reduce chronic disease risks’. However, they also added that such a diet ‘may lack critical nutrients such as vitamin B12, iron, zinc, iodine and omega-3 fatty acids, essential for neurodevelopment, immune function, and growth’ (Jahan-Mahan et al, 2024). Again, ‘deficiencies can lead to low birth weight, cognitive issues, and developmental delays’ (Jahan-Mahan et al, 2024).
In a prospective observational study of 273 women (112 omnivores, 37 fish-eaters, 64 lacto-ovo-vegetarians and 60 vegans), Avnon et al (2021) concluded that ‘the vegan diet is associated with an increased risk for small-for-gestational-age newborns and lower birthweight’. In a Danish prospective observational study of over 65 000 participants, Hedegaard et al (2024) found that ‘women reporting that they adhered to vegan diets during pregnancy had offspring with lower mean birthweight and higher risk of preeclampsia compared with omnivorous mothers’. The authors suggested that one possible explanation for the observed association with birthweight might be a low protein intake.
The importance of ‘specific dietary guidelines emphasising adequate intake of critical nutrients such as vitamin B12’, as outlined by Papadopoulou et al (2025), is underlined by two examples. First, the title of a paper by Kocaoglu et al (2014) is self-explanatory: ‘cerebral atrophy in a vitamin B12-deficient infant of a vegetarian mother’. Second, Guez et al (2012) described how an exclusively breastfed 5-month-old, born after a ‘normal full-term pregnancy to a vegan mother who was apparently daily treated with a multivitamin oral preparation during the second and third trimester, was hospitalised because of poor weight gain, feeding difficulties, severe pallor, muscle hypotonia and somnolence’.
Given the potentially health-challenging nature of vegetarian/vegan diets during pregnancy, midwives may have a useful role to play in offering informed nutritional advice to pregnant women. In a descriptive, cross-sectional, questionnaire-based Spanish observational study of 771 participants, Olloqui-Mundet et al (2025) presented participants with a list of 10 topics such as ‘general advice on nutrition in pregnancy’, ‘influence of diet on fetal development’, and ‘risk of over/underweight in pregnancy’. They found that ‘all topics on the list were rated as very important by more than 80% of the pregnant women, with the exception of “diet in vegan or vegetarian pregnant women”’ (Olloqui-Mundet et al, 2025).
Soh et al (2024) invited 14 dietitians, nurses, GPs and midwives to participate in their questionnaire-based New Zealand study that included semi-structured interviews. They noted that ‘plant foods provide absent or limited quantities of important micronutrients such as vitamin B12, iron, zinc, and omega-three fatty acids’ (Soh et al, 2024). More than 50% of participants disagreed that sufficient information about vegan diets during pregnancy and early life was available. In addition, ‘insufficient evidence-based consensus and government guidelines, and limited access and referrals to dietitians for guidance on vegan diets were highlighted as challenges that reduce the [sic] overall knowledge and confidence’ (Soh et al, 2024).
Midwives are an influential group who could help to shape the dietary landscape of pregnant women. Olloqui-Mundet et al (2025) suggested that ‘future research should investigate why midwives opt for general and not very personalised advice in order to assess whether nutrition education of pregnant women should be carried out by a multidisciplinary team with professionals specifically trained in the field of food and nutrition’. But with competing demands on midwives' time, the extent to which such suggestions are tenable will remain a topic for lively discussion.