title: Vegan-vegetarian diets in pregnancy: danger or panacea? A systematic narrative review.
abstract: BACKGROUND
  Although vegan-vegetarian diets are increasingly popular, no recent systematic reviews on vegan-vegetarian diets in pregnancy exist.
  
  
  OBJECTIVE
  To review the literature on vegan-vegetarian diets and pregnancy outcomes.
  
  
  METHODS
  PubMed, Embase, and the Cochrane library were searched from inception to September 2013 for pregnancy and vegan or vegetarian Medical Subject Headings (MeSH) and free-text terms.
  
  
  METHODS
  Vegan or vegetarian diets in healthy pregnant women. We excluded case reports and papers analysing vegan-vegetarian diets in poverty and malnutrition. Searching, paper selection, and data extraction were performed in duplicate.
  
  
  METHODS
  The high heterogeneity of the studies led to a narrative review.
  
  
  RESULTS
  We obtained 262 full texts from 2329 references; 22 selected papers reporting maternal-fetal outcomes (13) and dietary deficiencies (nine) met the inclusion criteria. None of the studies reported an increase in severe adverse outcomes or in major malformations, except one report of increased hypospadias in infants of vegetarian mothers. Five studies reported vegetarian mothers had lower birthweight babies, yet two studies reported higher birthweights. The duration of pregnancy was available in six studies and was similar between vegan-vegetarians and omnivores. The nine heterogeneous studies on microelements and vitamins suggest vegan-vegetarian women may be at risk of vitamin B12 and iron deficiencies.
  
  
  CONCLUSIONS
  The evidence on vegan-vegetarian diets in pregnancy is heterogeneous and scant. The lack of randomised studies prevents us from distinguishing the effects of diet from confounding factors. Within these limits, vegan-vegetarian diets may be considered safe in pregnancy, provided that attention is paid to vitamin and trace element requirements.
authors.affiliation: SS Nephrology, Department of Biological and Clinical Sciences, University of Torino, Torino, Italy.
authors.forename: G B
authors.initials: GB
authors.lastname: Piccoli
authors.forename: R
authors.initials: R
authors.lastname: Clari
authors.forename: F N
authors.initials: FN
authors.lastname: Vigotti
authors.forename: F
authors.initials: F
authors.lastname: Leone
authors.forename: R
authors.initials: R
authors.lastname: Attini
authors.forename: G
authors.initials: G
authors.lastname: Cabiddu
authors.forename: G
authors.initials: G
authors.lastname: Mauro
authors.forename: N
authors.initials: N
authors.lastname: Castelluccia
authors.forename: N
authors.initials: N
authors.lastname: Colombi
authors.forename: I
authors.initials: I
authors.lastname: Capizzi
authors.forename: A
authors.initials: A
authors.lastname: Pani
authors.forename: T
authors.initials: T
authors.lastname: Todros
authors.forename: P
authors.initials: P
authors.lastname: Avagnina
mesh_terms: D015986:Confounding Factors, Epidemiologic; D014676:Diet, Vegetarian / Q000009:adverse effects / Q000706:statistics & numerical data; D004044:Dietary Proteins / Q000008:administration & dosage*; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D039382:Maternal Nutritional Physiological Phenomena; D018673:Nutrition Policy; D009751:Nutritional Requirements; D011247:Pregnancy; D011256:Pregnancy Outcome; D012307:Risk Factors; D014815:Vitamins / Q000008:administration & dosage
chemical_list: D004044:Dietary Proteins; D014815:Vitamins
keywords: Birthweight; maternal-fetal outcomes; pregnancy; vegan diet; vegetarian diet