Table 3.
Description of studies conducted among pregnant and lactating women and their offspring
| Author (year) Country | Population | Design | Treatment/exposures | Dietary assessment methods | Participants (N) | Age at inclusion | Follow-up time | Outcomes |
|---|---|---|---|---|---|---|---|---|
| Koebnick 2004 Germany (20) | Pregnant | Prospective cohort | Adhering to lacto-ovo vegetarian diet, low meat diet or Western diet | 4-day semi-quantitative food record | N = 109 (27 lacto-ovo vegetarians, 43 low meat eaters, 39 controls) | Age: 29–31 years Gestational week: 9–12 |
From weeks 9–12 through 36–38 of gestation | s-B12, s-holo-TC, p-tHcy |
| Visentin 2016 Canada (21) | Pregnant | Prospective cohort | Dietary vitamin B12 intake | Block FFQ | N = 368 included (N = 364 at baseline, N = 309 at endpoint) | Age: 32 years Gestational week: 12–16 |
From week 12 to 16 until delivery | s-B12, p-MMA, p-tHcy |
| Denissen 2019 Netherlands (22) | Pregnant | Cross-sectional | Vitamin B12 intake | Semi-quantitative FFQ | N = 1266 | Age: 32.6 years Gestational week: Third trimester |
N/A | p-B12, p-holoTC, p-MMA |
| Greibe 2013 Denmark (23) | Lactation | Prospective cohort | Vitamin B12 intake from breastmilk | N/A | 60 Mother-child pairs | Mothers: Median age 30 years, 2 weeks postpartum Children: Birth |
9 months | B12 in breast milk, p-B12, p-holoTC, p-MMA |
| Henjum 2020 Norway (24) | Lactation | Cross-sectional | Maternal vitamin B12 intake from diet and supplement | FFQ | N = 193 (175 analysed) | Age: 32 years, 0–6 months postpartum | N/A | Breastmilk B12 |
| Hay 2008 Norway (25) | Lactation and infants | Prospective cohort | Vitamin B12 from diet and supplements | Questionnaire on intake of breastmilk or formula at 6 months, semi-quantitative FFQ and 7-day weighed food record at 12 months | N = 364 (249 at 12 months) | Mothers: Mean age 29.9 years Children: Birth | From birth until 2 years age | s-B12, s-holoTC, s-MMA, s-tHcy |