In a study of over 250 women (both pregnant and non-pregnant) based in Ireland, De Benedictus et al (2022) evaluated dietary intake and the bioavailability of zinc, finding that ‘58.14% of women and 38.39% of pregnant women participating in the study are at risk of inadequate zinc intake, and 29.07% of women and 9.28% of pregnant women may be considered zinc-deficient due to dietary inadequacy, based on their intake of bioavailable zinc’. The authors cited evidence that zinc absorption in vegetarian diets is between 15% and 26% instead of the 33% and 35% seen in omnivorous diets, because phytate-rich diets can inhibit zinc absorption in the small intestine. The authors then observed that ‘all participants whose food frequency questionnaires indicated a vegetarian diet were in the “at-risk” and “zinc-deficient” categories’ (De Benedictus et al, 2022).
A prospective observational Israeli study of 273 women (112 omnivores, 37 fish-eaters, 64 lacto—ovo—vegetarians, and 60 vegans) with a singleton pregnancy, who maintained the same diet before and throughout gestation, reported that ‘[t]he vegan diet was significantly associated with an increased risk of small-for-gestational-age newborns compared only to an omnivore diet’ (Avnon et al, 2021).
Buta and Tero-Vescan (2021) noted ‘an increased incidence of nutrient deficiencies in vegans, including omega-3 fatty acids, which is why, during pregnancy, when most daily requirements are higher, vegan women should consult a specialist to ensure proper supplementation’.
Such evidence raises the question not only of the health benefits conferred by strict plant-based diets, but also the extent to which midwives should be expected to offer evidence-based advice to pregnant women who follow such regimes. Although just over 1% of Great Britain's population is vegan, according to Meulenbroeks et al (2021), numbers have quadrupled over the last 5 years, with data from other western countries showing ‘that 75% of all vegans are women, and that 76—81% of all vegans are within the fertile age’.
Current trends in eating habits invite the inference that plant-based diets are being viewed favourably by more people today than they have been previously. The importance of being able to impart evidence-based dietary knowledge is becoming increasingly acute and is underlined by the thoughts of those who contributed to a position paper by the European Society for Paediatric Gastroenterology, Hepatology, and Nutrition (Fewtrell et al, 2017). Although the authors acknowledge that in theory the pursuit of a vegan diet can meet nutrient requirements when mother and infant take appropriate nutritional supplements following medical and dietary advice, ‘the risks of failing to follow advice are severe, including irreversible cognitive damage from vitamin B12 deficiency, and death. If a parent chooses to wean an infant onto a vegan diet this should be done under regular medical and expert dietetic supervision and mothers should receive and follow nutritional advice’ (Fewtrell et al, 2017).
Accepting both the potentially grave outcomes of ignoring medical and dietary advice, and the fact that we are living in what appears to be an evolving dietary landscape, how much confidence can pregnant women place in the nutritional advice they receive from their care team? In a cross-sectional, questionnaire-based Dutch study, Meulenbroeks et al (2021) evaluated the self-reported knowledge and advice given by 121 midwives, 179 obstetricians, and 111 dietitians when treating pregnant women on strict plant-based diets. Most midwives (80.2%) and obstetricians (93.9%) ‘considered a strict plant-based diet to be a significant risk factor for nutrient deficiency during pregnancy. Maternal dietary preferences, including a potential strict plant-based diet, were discussed at the first prenatal appointment by 59.5% of midwives and 24.1% of obstetricians’. Although a lack of knowledge concerning a strict plant-based diet was self-reported by 66.1% of midwives and 75.4% of obstetricians, it is perhaps surprising that ‘only 38.7% of dietitians indicated to have sufficient knowledge to counsel these women’, and interestingly, ‘a small group of midwives (12.4%) stated that it is also the responsibility of the patient themselves to find information on this topic (Meulenbroeks et al, 2021).
The recently published report examining maternity and neonatal services in East Kent (Kirkup, 2022) is harrowing, not least its observation that ‘there have been major service failures in Shrewsbury and Telford, in East Kent, and (it seems) in Nottingham. If we do not begin to tackle this differently, there will be more’. Given this grim context, one could reasonably speculate that dietary advice to pregnant women might not be the most urgent priority for midwives to address at this time.
However, Kirkup (2022) advises: ‘the NHS could be much better at identifying poorly performing units, at giving care with compassion and kindness, at teamworking with a common purpose, and at responding to challenge with honesty’. If such advice is followed, one can expect that future midwives will eventually need to address some of the diet-related havoc that is today being wrought by eating habits that place an undue emphasis on plant-based diets.