Diet is a critical factor in pregnancy(Reference Kaiser and Allen1). Adequate intake of macro- and micro-nutrients, along with heightened food safety practice, is pivotal for maternal and fetal health. In addition to efforts to satisfy nutritional and food safety guidelines, pregnant individuals navigate physiological changes, such as nausea, vomiting, cravings and aversions, all of which can have major impact on one’s appetite and eating behaviour(Reference Crozier, Inskip and Godfrey2). Globally, interest in plant-based dietary patterns and products appears to be increasing among consumers(Reference Mascaraque3) and public health organisations (e.g. The National Heart Foundation of New Zealand(4)), driven by increasing awareness of health and sustainability (e.g. the EAT-Lancet diet(Reference Willett, Rockström and Loken5)). Plant-based diets (PBD), broadly defined as a spectrum of diets restricting the intake of animal products(6), can potentially add further burden for pregnant individuals to meet a healthy diet for pregnancy.
While empirical evidence remains scarce, recent data from New Zealand (n 47 000) suggest 5·8 % of individuals identify as vegan or vegetarian(Reference Milfont, Satherley and Osborne7) – a dramatic increase over the 1 % reported by the 1997 New Zealand National Nutrition Survey (Russell et al. 1999). Globally, the reported prevalence of individuals following PBD varies from 1·8 % in Finland(Reference Lehto, Kaartinen and Sääksjärvi8) to 29 % of women in India(9). The growing popularity of PBD, particularly among females of reproductive age(Reference de Boer and Aiking10,Reference Pfeiler and Egloff11) , demands a better understanding of PBD during pregnancy, from both nutritional and behavioural perspectives.
Lack of adherence to national dietary guidelines during pregnancy is an ongoing public health challenge. In a cohort study of 5664 pregnant individuals in New Zealand, only 3 % completely met the Ministry of Health food intake guidelines(Reference Morton, Grant and Wall12), with similar low-adherence observed globally(Reference Slater, Rollo and Szewczyk13,Reference Saunders, Rehbinder and Carlsen14) . Although pregnant plant-based following populations are yet to be rigorously studied, clinical evidence suggests these individuals frequently experience sub-optimal nutritional status compared with omnivores; for example, dietary Zn intake during pregnancy was significantly lower among those following vegetarian diets(Reference Foster, Herulah and Prasad15), and a longitudinal cohort study found up to 39 % of vegetarians experienced vitamin B12 deficiency in at least one trimester of pregnancy(Reference Koebnick, Hoffmann and Dagnelie16). These data, along with evidence from non-pregnant, plant-based populations, demonstrate the need for healthcare systems to better support pregnant individuals consuming PBD.
Pregnant women are highly health-motivated, driven to achieve positive health and developmental outcomes for themselves and their infant(Reference Paterson, Hay-Smith and Treharne17,Reference Bookari, Yeatman and Williamson18) . Evidence suggests pregnant individuals consider health professionals to be important sources of nutrition information(Reference Bookari, Yeatman and Williamson18,Reference Brown, Von Hurst and Rapson19) , and nutritional counselling could have a positive effect on diet and maternal health outcomes, particularly among developing countries(Reference Girard and Olude20). Health professionals in regular contact with their pregnant patients are well placed to encourage healthy dietary patterns during pregnancy. In plant-based pregnancies, where individuals may require more support to achieve a well-planned diet, further importance is placed on the role of health professionals to help facilitate this. Although there is not yet a global, systematic evaluation of nutritional training for health professionals, available evidence from medical education suggests the curricula do not enable health professionals to give appropriate nutritional advice(Reference Crowley, Ball and Hiddink21).
The knowledge, attitudes and practices theoretical framework, frequently utilised in public health research, can provide broad insights into a topic or phenomena of interest(Reference Andrade, Menon and Ameen22). However knowledge, attitudes and practices research regarding health professionals in the context of plant-based diets and pregnancy is scarce; recent evidence suggests health professionals’ knowledge of PBD in pregnancy is limited(Reference Bettinelli, Bezze and Morasca23), and few studies have investigated attitudes or practices(Reference Meulenbroeks, Versmissen and Prins24). Therefore, a scoping review was conducted, utilising a diverse range of evidence sources to identify and map available evidence, identify gaps in the existing literature and shed light on reoccurring factors or characteristics related to the following research questions(Reference Munn, Peters and Stern25): What is known from the literature about the knowledge, attitudes and practices of health professionals regarding PBD in pregnancy? Does the knowledge and practices of health professionals in the reviewed studies align with relevant national dietary guidelines?
Method
Definitions
Recent interest from the scientific community has highlighted the need for clarity regarding the definitions of PBD. This review defines PBD as a continuum of dietary preferences(6), whereby an individual’s dietary energy obtained from animal sources is minimal, and compensated for by plant-based foods(Reference Hargreaves, Rosenfeld and Moreira26,Reference Kent, Kehoe and Flynn27) . PBD include dietary patterns such as vegan, vegetarian, and in some cases, semi-vegetarian, flexitarian, Mediterranean and some traditional or ancestral diets(Reference Hargreaves, Rosenfeld and Moreira26,Reference Kent, Kehoe and Flynn27) , outlined in Table 1.
Table 1 Definition of plant-based diets
Protocol and registration
Following a preliminary search of PROSPERO, MEDLINE, the Cochrane Database of Systematic Reviews and JBI Evidence Synthesis, no current or in-progress systematic or scoping reviews on the topic were identified. A protocol document was then developed following the Joana Briggs Institute methodology for scoping reviews(Reference Peters, Godfrey and McInerney28,Reference Peters, Marnie and Tricco29) , with reporting guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses, Scoping Reviews extension checklist(Reference Tricco, Lillie and Zarin30). The protocol was registered with the Open Science Framework (·https://doi.org/10·17605/OSF.IO/S97PX) prior to commencing the study and was unaltered during the course of the study.
Information sources, eligibility criteria and search
An initial search of Web of Science and MEDLINE (Ovid) identified key words used in the title, abstract and index terms of relevant papers. These informed the search strategy for the following, additional bibliographic databases, searched on 20 June 2023: Embase (Ovid), PsycInfo (Ovid), Global Health (Ovid), Scopus, CINAHL (EBSCO), Health and Medical Collection (ProQuest) and Dissertations and Theses Global (ProQuest). Search strings used are available in Appendix A. Grey literature sources were searched using an adapted search string, including university research repositories in New Zealand, reference lists of included publications and the first 100 results on Google Scholar. The search was restricted to reports published in the English language due to limited resources for accurate language translation, and reports published in the past 30 years, due to changing healthcare systems and the relatively recent interest in PBD. Identified records were exported via EndNote v.20 (Clarivate Analytics, PA, USA) to Rayyan (Qatar Computing Research Institute, Doha, Qatar) for screening by two authors, SM and JM.
Selection of sources of evidence
SM and JM independently screened study titles and abstracts against the criteria presented in Table 2. Abstracts that appeared to meet the inclusion criteria were retained for full text screening. Full texts were independently retrieved by SM and JM and screened against the inclusion criteria. Any disagreements were discussed and resolved upon completion of the screening process. SM manually searched the reference lists of the included studies for any relevant reports, which were then subject to the same screening procedure.
Table 2 Inclusion and exclusion criteria for publications included in review
PBD, Plant-based diets.
Data charting process
SM completed data charting independently, using an instrument adapted from JBI(Reference Peters, Marnie and Tricco29). The following variables were charted: year, authors, title, geographic location, study design, primary aim of the study, methodology, number of participants, roles of health professionals, plant-based dietary patterns referenced and definitions, participant’s own dietary pattern, knowledge of PBD nutrition in pregnancy, attitudes towards PBD in pregnancy and practices regarding pregnant individuals following PBD (for example, early testing for Fe deficiency). When not explicitly defined, attitudes were interpreted as questions pertaining to beliefs, expectations or opinions. Qualitative data were charted using a deductive approach, with knowledge, attitudes and practices as the pre-decided categories(Reference Elo and Kyngäs31,Reference Pollock, Peters and Khalil32) . The included studies were assessed for quality using the Mixed Methods Appraisal Tool(Reference Hong, Pluye and Fàbregues33). This optional step was included to enable a more in-depth exploration of the reported results. Lastly, a narrative synthesis was performed, grouping the data by knowledge, attitudes and practices.
Results
A total of 3057 articles were found. Of these, 1698 were duplicates and were excluded by automatic detection (n 1053) and after review by SM (n 645). SM and JM independently screened the remaining 1359 articles against the inclusion and exclusion criteria, based on study title and abstract. Seventy-five articles were eligible for full-text screening, of these, 10 were included for review as outlined in Fig. 1. The remaining sixty-five articles were excluded for not being published in English language (n 1), not assessing PBD in pregnancy (n 31), study participants were not health professionals (n 6), study was a review, opinion piece or practice guideline (n 25) and for being published prior to 1993 (n 2). One study was excluded at the data charting stage, due to the results not being relevant to the current review, and one additional study was included after citation searching.
Fig. 1 Flow chart of included studies. Note. Source: (Reference Tricco, Lillie and Zarin30,Reference Jeitler, Storz and Steckhan34) .
All studies were published between 1995 and 2022, although the majority were published in the last 5 years. Despite diverse geographic locations of these studies, including five from European countries (Netherlands, Germany, Italy, France and United Kingdom) (n 5)(Reference Bettinelli, Bezze and Morasca23,Reference Meulenbroeks, Versmissen and Prins24,Reference Jeitler, Storz and Steckhan34–Reference Mulliner, Spiby and Fraser36) , four from the Oceania region (Australia (n 2) and New Zealand (n 2))(Reference Othman, Steen and Fleet37–Reference Soh40) and one from Latin America (i.e. Peru)(Reference Saintila, Calizaya-Milla and Javier-Aliaga41), it is important to note that these countries may share similar westernised dietary patterns(Reference McCloskey, Tarazona-Meza and Jones-Smith42). The studies were all peer-reviewed, except for one master’s thesis(Reference Soh40). The studies were most frequently cross sectional (n 9), with the exception of one intervention(Reference Othman, Steen and Fleet37) conducted in Australia. Study characteristics are presented in Appendix B. Most studies were of high quality, and results of the critical appraisal are presented in Appendix C.
The studies assessed knowledge, attitudes or practices of health professionals with regard to: PBD in pregnancy (n 4)(Reference Bettinelli, Bezze and Morasca23,Reference Meulenbroeks, Versmissen and Prins24,Reference Soh40,Reference Saintila, Calizaya-Milla and Javier-Aliaga41) , general nutrition in pregnancy with aspects of the research directly relevant to PBD (n 5)(Reference Villette, Vasseur and Lapidus35–Reference Elias and Green39) or PBD with aspects relevant to pregnancy (n 1)(Reference Jeitler, Storz and Steckhan34). Designs included quantitative (n 6), qualitative (n 1), mixed methods (n 2) or intervention (n 1). Most of the studies used a survey instrument developed or adapted for the study, for example, both Saintila and colleagues(Reference Saintila, Calizaya-Milla and Javier-Aliaga41) and Soh(Reference Soh40) adapted a survey instrument developed by Bettinelli and colleagues(Reference Bettinelli, Bezze and Morasca23), employing similar question phrasing and assessment. The qualitative designs employed interviews conducted in-person(Reference Mulliner, Spiby and Fraser36,Reference Othman, Fleet and Steen38) , via telephone(Reference Othman, Fleet and Steen38) or video call(Reference Soh40), and the intervention study utilised a nutrition-education programme, evaluated using pre and post intervention surveys developed for the study(Reference Othman, Steen and Fleet37).
A variety of health professionals were included in the study cohorts, including only midwives (n 3)(Reference Mulliner, Spiby and Fraser36,Reference Othman, Fleet and Steen38,Reference Elias and Green39) , health professionals working in clinical or community settings, including midwives, obstetricians, general practitioners, paediatricians, nurses, dietitians, nutritionists, health support workers and a paediatric registrar (n 5)(Reference Bettinelli, Bezze and Morasca23,Reference Meulenbroeks, Versmissen and Prins24,Reference Villette, Vasseur and Lapidus35,Reference Soh40,Reference Lee, Newton and Radcliffe43) . One study included only dietitians(Reference Saintila, Calizaya-Milla and Javier-Aliaga41), and one study cohort consisted of a group of health professionals attending a plant-based nutrition conference(Reference Jeitler, Storz and Steckhan34). These participants were predominantly medical doctors, although dietitians, nutritionists, nutritional scientists, alternative health professionals, pharmacists and other unspecified health professionals were included in the responses(Reference Jeitler, Storz and Steckhan34). Most participants engaged with patients at a primary or secondary level of healthcare, either in a hospital maternity unit, antenatal clinic, general practitioner clinic or independent practice. Sample sizes ranged from 7 to 475 participants. The studies’ geographic location, participants’ profession and dietary pattern, and main findings related to knowledge, attitudes, and practices are summarised in Table 3.
Table 3 Relevant findings from the reviewed literature
PBD, plant-based diets; n-3 PUFA, long-chain polyunsaturated fatty acid; GP, general practitioner; LOV, lacto-ovo vegetarian.
Knowledge of nutrition related to plant-based diets during pregnancy
Participants reported concerns about their lack of knowledge with regard to PBD, including a lack of confidence advising on, or discussing PBD in pregnancy(Reference Mulliner, Spiby and Fraser36,Reference Elias and Green39) , and a limited ability to effectively advise individuals following PBD in pregnancy(Reference Meulenbroeks, Versmissen and Prins24). Frequently reported sources of knowledge or information used by health professionals included: knowledge gained from education(Reference Othman, Fleet and Steen38,Reference Elias and Green39) , brochures, pamphlets and information sheets distributed by organisations or government publications(Reference Othman, Fleet and Steen38–Reference Soh40), scientific journals(Reference Soh40), nutrition organisations(Reference Elias and Green39) and general knowledge(Reference Elias and Green39).
Just over half of the studies (n 6) assessed knowledge of nutrients critical for maternal health and infant development(Reference Bettinelli, Bezze and Morasca23,Reference Villette, Vasseur and Lapidus35,Reference Othman, Steen and Fleet37,Reference Elias and Green39–Reference Saintila, Calizaya-Milla and Javier-Aliaga41) , with one study assessing this knowledge following a nutrition education intervention(Reference Othman, Steen and Fleet37). Four of these studies(Reference Bettinelli, Bezze and Morasca23,Reference Othman, Steen and Fleet37,Reference Elias and Green39,Reference Soh40) included questions to directly assess participants’ knowledge of nutrition and PBD in pregnancy, for example, asking what nutrient a vegan mother is most at risk of being deficient in(Reference Bettinelli, Bezze and Morasca23). Lastly, two studies(Reference Villette, Vasseur and Lapidus35,Reference Saintila, Calizaya-Milla and Javier-Aliaga41) reported on knowledge of nutrients relevant to PBD in pregnancy, although these questions were framed in a generalised manner, for example, asking about the bioavailability of plant-based protein(Reference Saintila, Calizaya-Milla and Javier-Aliaga41). An overview of the nutrients assessed and the question context is presented in Appendix D.
Micronutrients
Micronutrients frequently assessed included B vitamins (n 6)(Reference Bettinelli, Bezze and Morasca23,Reference Villette, Vasseur and Lapidus35,Reference Othman, Steen and Fleet37,Reference Elias and Green39–Reference Saintila, Calizaya-Milla and Javier-Aliaga41) , Fe (n 4)(Reference Villette, Vasseur and Lapidus35,Reference Elias and Green39–Reference Saintila, Calizaya-Milla and Javier-Aliaga41) and Zn (n 5)(Reference Bettinelli, Bezze and Morasca23,Reference Villette, Vasseur and Lapidus35,Reference Elias and Green39–Reference Saintila, Calizaya-Milla and Javier-Aliaga41) . Participants’ self-reported lack of knowledge was frequently demonstrated through low scores on these knowledge assessments. While the majority of health professionals surveyed across studies identified the importance of these micronutrients, both in the general population(Reference Villette, Vasseur and Lapidus35,Reference Saintila, Calizaya-Milla and Javier-Aliaga41) and during pregnancy(Reference Bettinelli, Bezze and Morasca23,Reference Othman, Steen and Fleet37,Reference Soh40) , few health professionals were able to accurately identify dietary sources(Reference Elias and Green39,Reference Soh40) . A notable exception to this is Fe. Knowledge of dietary sources of Fe was reasonably high among midwives and other antenatal carers surveyed in New Zealand, with more than two-thirds correctly identifying molasses(Reference Elias and Green39) and legumes(Reference Elias and Green39,Reference Soh40) as dietary sources. However, by contrast, more than two-thirds also incorrectly identified spirulina as a good source of Fe(Reference Elias and Green39). Surprisingly, these studies suggest most participants correctly identified vitamin C as an enhancer of and tannins as an inhibitor of Fe absorption(Reference Elias and Green39,Reference Soh40) .
n-3 PUFA were briefly mentioned in five studies(Reference Bettinelli, Bezze and Morasca23,Reference Villette, Vasseur and Lapidus35,Reference Othman, Steen and Fleet37,Reference Soh40,Reference Saintila, Calizaya-Milla and Javier-Aliaga41) , despite a growing body of evidence demonstrating their importance in fetal development(Reference Larqué, Gil-Sánchez and Prieto-Sánchez44). A similar pattern of knowledge was evident, with health professionals surveyed by Soh(Reference Soh40) recognising the importance of n-3 PUFA during pregnancy (for example, participants correctly stated pregnant individuals following vegan diets are more at risk of n-3 PUFA deficiency(Reference Soh40)), yet lacked understanding of dietary sources(Reference Othman, Steen and Fleet37), and the physiological implications of limited plant-based dietary intake(Reference Bettinelli, Bezze and Morasca23,Reference Saintila, Calizaya-Milla and Javier-Aliaga41) .
Vitamins A, C, D, Ca and iodine were assessed in four studies(Reference Villette, Vasseur and Lapidus35,Reference Othman, Steen and Fleet37,Reference Soh40,Reference Saintila, Calizaya-Milla and Javier-Aliaga41) , most frequently as part of a broad, multi-answer questions, such as listing supplements recommended for individuals following PBD in pregnancy (e.g.(Reference Soh40)).
Macronutrients
Protein was the only macronutrient assessed in any of the included studies. Questions around protein included knowledge of dietary sources (n 1)(Reference Othman, Steen and Fleet37), bioavailability (n 2)(Reference Bettinelli, Bezze and Morasca23,Reference Saintila, Calizaya-Milla and Javier-Aliaga41) , importance in PBD (n 1)(Reference Saintila, Calizaya-Milla and Javier-Aliaga41) and risks of deficiency (n 2)(Reference Villette, Vasseur and Lapidus35,Reference Soh40) . Knowledge of protein was moderate among midwives both before and after the nutrition education intervention, with approximately two-thirds correctly identifying (predominantly animal-based) dietary sources of protein(Reference Othman, Steen and Fleet37). Of the three studies investigating bioavailability, only one-fifth of antenatal-carers recognised the limited bioavailability of plant-based protein(Reference Bettinelli, Bezze and Morasca23), compared with more than three quarters of dietitians(Reference Saintila, Calizaya-Milla and Javier-Aliaga41).
Attitudes and beliefs towards plant-based diets in pregnancy
Six studies assessed attitudes towards PBD in pregnancy. The studies employed various techniques, most frequently using Likert scales to elicit agreement or disagreement with statements or questions regarding beliefs or expectations. Positive attitudes were evident in three studies(Reference Bettinelli, Bezze and Morasca23,Reference Villette, Vasseur and Lapidus35,Reference Soh40) , for example, most dietitians surveyed by Saintila(Reference Saintila, Calizaya-Milla and Javier-Aliaga41) agreed that a planned PBD is appropriate for all stages of life, regardless of their personal dietary preferences(Reference Saintila, Calizaya-Milla and Javier-Aliaga41). In one instance, the positive attitudes reported were tempered through follow-up questions; Soh(Reference Soh40) reports most health professionals agreed a B-12 supplemented, well-planned vegan was suitable for pregnancy, although half were unsure as to whether this could promote positive health outcomes(Reference Soh40). Almost two-thirds of dietitians believed planned PBD during pregnancy do not increase an individual’s chance of experiencing a difficult pregnancy or birth defects(Reference Saintila, Calizaya-Milla and Javier-Aliaga41). Health professionals following PBD themselves were significantly more likely to agree PBD (vegan) are nutritionally adequate during pregnancy than health professionals following non-PBD(Reference Jeitler, Storz and Steckhan34).
However, negative attitudes towards PBD in pregnancy were also observed (n 3)(Reference Bettinelli, Bezze and Morasca23,Reference Meulenbroeks, Versmissen and Prins24,Reference Villette, Vasseur and Lapidus35) , expressed via poor expectations regarding pregnancy-related difficulties or birth defects (n 1)(Reference Meulenbroeks, Versmissen and Prins24) or plant-based pregnancy outcomes (n 2)(Reference Bettinelli, Bezze and Morasca23,Reference Villette, Vasseur and Lapidus35) . For example, most midwives and obstetricians surveyed by Meulenbroeks and colleagues(Reference Meulenbroeks, Versmissen and Prins24) agreed with the statement ‘Expect increased risk for developing deficiencies on a plant-based diet’(Reference Meulenbroeks, Versmissen and Prins24). Similar findings were observed by Bettinelli and colleagues(Reference Bettinelli, Bezze and Morasca23) and Villette and colleagues(Reference Villette, Vasseur and Lapidus35). A study investigating the beliefs and attitudes of general practitioners and paediatricians in France reported almost all participants believed a vegan diet was unsuitable for pregnancy or lactation(Reference Villette, Vasseur and Lapidus35). Beliefs regarding lacto-ovo vegetarian diets were more moderate – approximately half believed a lacto-ovo vegetarian diet was unsuitable(Reference Villette, Vasseur and Lapidus35).
Midwives, obstetricians and other health professionals surveyed appear to take professional responsibility for advising pregnant individuals on nutrition(Reference Elias and Green39) and those following PBD(Reference Meulenbroeks, Versmissen and Prins24,Reference Soh40) , despite the admission that their knowledge is not sufficient. In addition to this, most midwives and nearly two-thirds of obstetricians surveyed believed these individuals require extra care during their pregnancy(Reference Meulenbroeks, Versmissen and Prins24).
Practices
Four studies reported on the practices of health professionals with regard to PBD in pregnancy(Reference Meulenbroeks, Versmissen and Prins24,Reference Mulliner, Spiby and Fraser36,Reference Othman, Fleet and Steen38,Reference Soh40) . Less than 3 % of midwives and obstetricians reported having a practice protocol for managing PBD in pregnancy(Reference Meulenbroeks, Versmissen and Prins24). Frequently mentioned practices included referrals to dietitians(Reference Meulenbroeks, Versmissen and Prins24,Reference Mulliner, Spiby and Fraser36,Reference Othman, Fleet and Steen38,Reference Soh40) , giving nutritional advice and ordering blood tests to assess vitamin status(Reference Meulenbroeks, Versmissen and Prins24) and distributing pamphlets or other ‘information sheets’(Reference Othman, Fleet and Steen38). In contrast to the midwives surveyed by Meulenbroeks and colleagues(Reference Meulenbroeks, Versmissen and Prins24), obstetricians surveyed in the same study most frequently reported performing blood tests to analyse vitamin status, followed by prescribing supplements, and referring to a dietitian(Reference Meulenbroeks, Versmissen and Prins24). A number of barriers were noted toward implementing these practices: referrals were limited by difficulty in accessing dietitian services(Reference Soh40), and provision of resources appeared to be dependent on the availability at the clinic, and are predominantly aimed at general nutrition and food safety in pregnancy(Reference Othman, Fleet and Steen38), for example, minimising exposure to toxoplasmosis.
Dietary guidelines
Of the reviewed studies, only five commented on health professional knowledge of established dietary guidelines regarding PBD during pregnancy, with only one study specifically including this aspect in their research scope(Reference Jeitler, Storz and Steckhan34). Health professionals surveyed by Jeitler and colleagues(Reference Jeitler, Storz and Steckhan34) demonstrated moderate knowledge of the German and American nutrition societies’ position statements regarding the suitability of PBD during pregnancy, with respondents following vegan diets scoring significantly higher compared with those following vegetarian or omnivorous diets. The qualitative interviews conducted by Soh(Reference Soh40) revealed both a perceived lack of relevant information in the New Zealand dietary guidelines, and the importance of having more detailed, evidence-based guidelines for health professionals to reference.
The remaining three studies referenced a wide variety of guidelines during survey development(Reference Bettinelli, Bezze and Morasca23,Reference Othman, Steen and Fleet37) or modification(Reference Saintila, Calizaya-Milla and Javier-Aliaga41), including both country-specific(Reference Bettinelli, Bezze and Morasca23,Reference Othman, Steen and Fleet37) and international(Reference Saintila, Calizaya-Milla and Javier-Aliaga41). Only Othman and colleagues(Reference Othman, Steen and Fleet37) directly questioned knowledge of these guidelines in questions unrelated to PBD. The survey developed by Bettinelli and colleagues(Reference Bettinelli, Bezze and Morasca23) and later modified by Saintila and colleagues(Reference Saintila, Calizaya-Milla and Javier-Aliaga41), contained a knowledge question regarding the appropriateness of PBD during pregnancy and appeared to be based on the often-cited American Dietetic Association guidance, stating a well-planned PBD was appropriate for pregnancy(45).
Influences on knowledge and attitudes towards plant-based diets
Health professionals’ knowledge, attitudes and practices appeared to be moderated by their professional specialisation. For example, dietitians scored consistently higher when answering nutrition knowledge questions(Reference Saintila, Calizaya-Milla and Javier-Aliaga41), compared with other health professionals such as nurses and midwives(Reference Bettinelli, Bezze and Morasca23). In addition, more dietitians reported having sufficient knowledge to advise pregnant individuals following PBD (39 %), compared with midwives (24 %) and obstetricians (7 %), though the overall proportion reporting sufficient knowledge remains low(Reference Meulenbroeks, Versmissen and Prins24).
Attitudes of dietitians were frequently positive towards PBD in pregnancy, with more than two-thirds disagreeing with a statement claiming PBD in pregnancy increase an individuals’ risk of pregnancy complications and birth defects(Reference Saintila, Calizaya-Milla and Javier-Aliaga41), compared with one-third of other health professionals (nurses, midwives and health care support workers)(Reference Bettinelli, Bezze and Morasca23).
Half of the studies reported participants’ own dietary patterns (n 5)(Reference Bettinelli, Bezze and Morasca23,Reference Jeitler, Storz and Steckhan34,Reference Villette, Vasseur and Lapidus35,Reference Soh40,Reference Saintila, Calizaya-Milla and Javier-Aliaga41) . PBD were followed by between 5 and 22·5 % of participants(Reference Bettinelli, Bezze and Morasca23,Reference Villette, Vasseur and Lapidus35,Reference Soh40) . One study specifically recruited vegetarian participants, thus 40 % of their cohort reported following vegetarian diets(Reference Saintila, Calizaya-Milla and Javier-Aliaga41). Lastly, one study took place at plant-based nutrition conference, where 74 % of participants reported following plant-based dietary patterns(Reference Jeitler, Storz and Steckhan34). Participants’ own dietary patterns appear to influence their knowledge, attitudes and practices with regard to PBD in pregnancy. This is particularly apparent in Bettinelli and colleagues(Reference Bettinelli, Bezze and Morasca23) study, where significantly more vegetarian health professionals correctly answered questions regarding the appropriateness of a planned PBD during different life stages including pregnancy, lactation and infancy(Reference Bettinelli, Bezze and Morasca23). Similar quantitative results were observed among dietitians(Reference Saintila, Calizaya-Milla and Javier-Aliaga41) and other health professionals(Reference Jeitler, Storz and Steckhan34). This was further demonstrated through interviews with various health professionals, who revealed attitudes towards individuals following PBD in pregnancy, were more positive if they had personal experience of them(Reference Soh40).
Discussion
Poor-to-moderate knowledge of plant-based nutrition in pregnancy
In line with recent global interest in plant-based eating(Reference Mascaraque3), PBD in public health(4) and sustainable nutrition(Reference Willett, Rockström and Loken5), there is a growing interest in PBD from the scientific community. It is apparent from the lack of knowledge both demonstrated and self-reported by the health professionals that this increased understanding at an academic level is yet to be reflected in evidence-based practice. Most publications reviewed were published in the last 5 years, yet compared with the two earliest publications(Reference Mulliner, Spiby and Fraser36,Reference Elias and Green39) , the challenge of a lack of knowledge or confidence with regard to PBD in pregnancy appears unchanged(Reference Meulenbroeks, Versmissen and Prins24,Reference Villette, Vasseur and Lapidus35,Reference Othman, Steen and Fleet37) .
Despite general awareness of micronutrients relevant to PBD in pregnancy, there appears to be limited understanding regarding how these micronutrients fit into a dietary context. An interesting exception to this is Fe – two studies revealed an understanding of absorption enhancers and inhibitors, a relatively advanced nutrition concept(Reference Elias and Green39,Reference Soh40) . Both studies also revealed the health professionals referenced a variety of sources for nutrition information. These include reliable, evidence-based sources such as nutrition organisations, scientific journals and governmental publications, to publications from industry organisations with commercial interests, such as Beef + Lamb New Zealand Incorporated (Beef + Lamb NZ), funded by farmers, retailers and meat processors, with the purpose of promoting the New Zealand beef and lamb industry. The use of potentially biased, industry-sourced material in a health care setting is surprising. However, we speculate the consumer-friendly publications and marketing campaigns promoting Fe from organisations such as Beef + Lamb NZ, in addition to detailed dietary guidelines published by the New Zealand government (e.g. Eating and Activity Guidelines(46)) may increase familiarity of Fe, including knowledge of various dietary sources, and foods that can promote or inhibit absorption. In addition, Fe intake is recognised as a common concern during pregnancy, and Fe deficiency or anaemia can occur as a result of poor dietary intake(Reference Goonewardene, Shehata and Hamad47), or increased blood volume resulting in haemodilution(Reference Koller48). As such, Fe status is regularly tested during pregnancy, and despite reported practice inconsistencies(Reference Calje and Skinner49), this would ultimately contribute to a heightened awareness.
The health professionals surveyed in the reviewed studies frequently attributed their own lack of knowledge to a lack of training and education in plant-based nutrition. Of the studies’ participants, dietitians are the most specialised regarding nutrition and dietary advice, yet their training regarding plant-based diets in pregnancy is reportedly infrequent(Reference Meulenbroeks, Versmissen and Prins24). It is likely due to specialised knowledge of relevant micro- and macro-nutrients, and general pregnancy dietary requirements that dietitians report higher levels of confidence when advising pregnant individuals following PBD, compared with other health professionals(Reference Meulenbroeks, Versmissen and Prins24).
In practice, it is often midwives and other antenatal care providers, not dietitians, who are responsible for giving dietary advice during pregnancy. This is a view held by pregnant individuals(Reference Brown, Von Hurst and Rapson19), other health professionals(Reference Meulenbroeks, Versmissen and Prins24) and midwives themselves(Reference Meulenbroeks, Versmissen and Prins24,Reference Arrish, Yeatman and Williamson50) . Despite this responsibility, midwives surveyed report their nutrition education regarding PBD and pregnancy as being insufficient(Reference Meulenbroeks, Versmissen and Prins24). This is particularly concerning, considering midwives frequently rely on their undergraduate education for their nutrition knowledge(Reference Othman, Fleet and Steen38,Reference Elias and Green39,Reference Arrish, Yeatman and Williamson51) . This misalignment between the apparent role of midwives in providing advice, and the training, resources and support provided must be addressed, and the curricula adapted to reflect global changes in diet.
Othman and colleagues(Reference Othman, Steen and Fleet37) demonstrated the effective use of a nutrition education intervention for midwives, resulting in a significant improvement in pregnancy nutrition knowledge (including aspects related to PBD). While follow-up studies within this demographic are scarce, evidence suggests continuing professional development could be used as an effective tool to upskill this group(Reference Othman, Steen and Fleet37).
Participant factors influencing attitudes, knowledge and practices
Attitudes towards PBD in pregnancy range from positive to negative, appear to be associated with personal dietary patterns, and professional specialisation. Attitude formation is influenced by a range affective (emotional) and cognitive (knowledge-based) factors(Reference Ajzen52). This model can be used to shed light on the role of personal dietary patterns and professional specialisation regarding PBD in pregnancy.
Professional specialisation
When reported, health professionals with nutrition-focused specialisations, such as dietitians, appeared to view PBD in pregnancy more favourably(Reference Saintila, Calizaya-Milla and Javier-Aliaga41), in addition to demonstrating an increased level of knowledge compared with other health professionals surveyed. We hypothesise the knowledge and confidence acquired during training or professional development(Reference Othman, Steen and Fleet37) contributes to the positive attitudes displayed by this cohort(Reference Ajzen52). One study did not find a significant association between professional specialisation and attitude(Reference Jeitler, Storz and Steckhan34); however, the cohort was a convenience sample of health professionals attending a plant-based nutrition conference, of which the majority followed PBD. Thus, we would expect this cohort to have positive attitudes towards PBD regardless of their specialisation.
Personal dietary patterns
Previous research has demonstrated individuals display positive attitudes towards their own dietary pattern and negative attitudes or beliefs regarding other diets(Reference Povey, Wellens and Conner53), consistent with findings of the reviewed studies. Of the studies that investigated health professionals’ own dietary preferences, most reported participants following PBD were more likely to have a positive attitude towards their patients following PBD in pregnancy(Reference Bettinelli, Bezze and Morasca23,Reference Jeitler, Storz and Steckhan34,Reference Saintila, Calizaya-Milla and Javier-Aliaga41) . Soh’s(Reference Soh40) qualitative interviews support these findings, and the remaining study(Reference Villette, Vasseur and Lapidus35) did not report relevant analysis. We hypothesise personal dietary patterns influence health professionals’ attitudes in two ways; cognitively, by increasing their knowledge, understanding and awareness of PBD and affectively, through the recognition or affirmation of their own dietary choices(Reference Povey, Wellens and Conner53). The chances of encountering a health professional following a PBD is low, yet for individuals following PBD, their quality of care could be significantly influenced by this.
Research gap in health professionals’ practices regarding plant-based diets in pregnancy
There is limited evidence regarding practices of health professionals when caring for pregnant individuals following PBD. In the current review, the four studies that reported on professional practices all included midwives(Reference Meulenbroeks, Versmissen and Prins24,Reference Mulliner, Spiby and Fraser36,Reference Othman, Fleet and Steen38,Reference Soh40) , one group of obstetricians(Reference Meulenbroeks, Versmissen and Prins24) and a small number of other antenatal care providers(Reference Soh40). Few health professionals reported having a practice protocol to treat pregnant individuals following PBD(Reference Meulenbroeks, Versmissen and Prins24). Given the demonstrated lack of knowledge and confidence with regard to PBD in pregnancy, a protocol could promote better care among these groups. Although referrals to dietitians were frequently mentioned, it is unclear how effective this is in practice – dietitians report moderate knowledge on PBD in pregnancy(Reference Meulenbroeks, Versmissen and Prins24) and reported difficulties accessing their services(Reference Soh40). While the majority of Soh’s (2022) cohort believed individuals following PBD in pregnancy should take Fe and Vitamin B12 supplements, it is unclear whether this is followed through in practice(Reference Soh40).
Dietary guidelines
While a few studies commented on the appropriateness of well-planned PBD for pregnancy in line with the American Dietetic Association position statement(45), there appears to be limited research with a specific focus on how health professionals incorporate national dietary guidelines regarding PBD into their practice. The omission of country specific dietary guidelines from these investigations may be due to their lack of detailed, relevant information, e.g. Peru(Reference Lázaro Serrano and Domínguez Curi54), or in some instances, discouragement of PBD during pregnancy, e.g. Germany and Italy(55,56) . As a result, a number of the surveys referenced guidelines from countries different to the study population(Reference Bettinelli, Bezze and Morasca23,Reference Saintila, Calizaya-Milla and Javier-Aliaga41) . Although dietary guidelines are evidence-based and created following rigorous methodology(Reference Zeraatkar, Johnston and Guyatt57), they are country-specific, and designed to cover a range of groups within the national population. For example, New Zealand and Australia share a food standards regulatory body, yet develop different dietary guidelines culturally appropriate for their populations(Reference Baghurst58).
Results from the studies conducted in Germany and Italy(Reference Bettinelli, Bezze and Morasca23,Reference Jeitler, Storz and Steckhan34) , indicating the majority of health professionals following PBD agree they are suitable for pregnancy, are somewhat incongruous with the German and Italian dietary guidelines. While this may be demonstrative of health professionals’ subjective experience positively influencing their attitudes towards PBD in pregnancy(Reference Jeitler, Storz and Steckhan34), it also suggests the level of knowledge required by these health professionals would go beyond that contained in the dietary guidelines. This is not unreasonable for nutritionists or dietitians, but for midwives or health professionals responsible for numerous aspects of maternal care, having this specialist knowledge is likely unfeasible.
Strengths and limitations
Although few studies were eligible for review, the geographic spread of the literature enabled a diverse range of evidence to be summarised and reviewed. Despite this, almost all the studies reviewed were observational and identified numerous research gaps. Unfortunately, only one study used an education intervention designed to address some of these knowledge gaps(Reference Othman, Steen and Fleet37). While the intervention demonstrated an overall improvement in health professional knowledge, the study was limited by a small sample size, high attrition rate and a limited range of questions used to assess changes in nutrition knowledge(Reference Othman, Steen and Fleet37).
The current review used a systematic approach to perform a scoping review, allowing for inclusion of evidence from a wide range of sources. Despite the rigorous approach, some limitations must be noted. Restricting results by language may have led to the omission of some non-English, non-Western literature.
Although the studies included are from a diverse range of geographic locations, they are all upper-middle- (Peru) and high income, with established health-care systems that require extensive education and training to work as health professionals. In some instances, this may limit the relevance of these results to developing nations, whose populations are more at risk of undernutrition (e.g. increased prevalence of Fe deficiency anaemia(Reference Karami, Chaleshgar and Salari59)), and experience limited access to high-quality antenatal care(Reference Benova, Tunçalp and Moran60).
Implications
There is a growing movement to implement better nutrition education for health professionals, yet even health professionals with nutrition specialisations feel ill-prepared to counsel pregnant individuals following PBD. There is a clear need for specific curriculum regarding PBD during pregnancy, tailored to the health professionals frequently involved in antenatal care, such as midwives, obstetricians and family doctors. It is apparent researchers must encourage the translation of the growing body of evidence regarding PBD into clinical practice and the public health sphere, along with conducting further research utilising intervention study designs. More broadly, the increasing interest in PBD among women of reproductive age demands greater understanding of clinical outcomes, such as perinatal depression, macronutrient intake and corresponding gestational weight changes. For the increasing number of individuals following PBD during pregnancy, the difference between optimal or sub-optimal care with regard to dietary advice may be determined by geographic location and the knowledge and attitudes of the health professionals encountered.
Conclusion
This scoping review investigated the knowledge, attitudes and practices of health professionals, with regard to plant-based diets in pregnancy. Ten articles were eligible for review, revealing a sparse body of literature. Three main findings were identified: (1) Health professionals’ knowledge of plant-based nutrition in pregnancy is limited, this is frequently attributed to a lack of nutrition education; (2) Health professionals’ own dietary patterns and their professional specialisation are associated with their knowledge, attitudes and practices and (3) there is a significant research gap regarding health professionals’ practices with regard to PBD in pregnancy. Further avenues of research include studies investigating the knowledge, attitudes and practices of health professionals from specialisations such as general practice; studies to determine the impact of knowledge of and attitudes towards PBD on the practices of health professionals and a continuation of the standardised survey that is beginning to be implemented in this field of research to enable a systematic review and meta-analysis of the evidence.
Financial support
Riddet Institute and Marsden Fund (UOO_2119) funded this project. The first author is the recipient of a University of Otago Doctoral Scholarship.
Conflicts of interest
There are no conflicts of interest.
Authorship
Stephanie C. McLeod: Conceptualization, Investigation, Methodology, Project administration, Data curation, Writing – original draft. Jessica C. McCormack: Conceptualization, Investigation, Methodology, Writing – review & editing. Indrawati Oey: Funding acquisition, Writing – review & editing. Tamlin S. Conner: Methodology, Writing – review & editing. Mei Peng: Conceptualization, Funding acquisition, Methodology, Resources, Supervision, Writing – review & editing.
Ethics of human subject participation
Not applicable.
Supplementary material
For supplementary material accompanying this paper visit https://doi.org/10.1017/S1368980024001484
Open access
