Nithya Sukumar1, Snorri B Rafnsson2, Ngianga-Bakwin Kandala3, Raj Bhopal4, Chittaranjan S Yajnik5, Ponnusamy Saravanan6. 1. Division of Health Sciences, Populations, Evidence, and Technologies Group, Warwick Medical School, The University of Warwick, Coventry, United Kingdom; 2. Department of Epidemiology and Public Health, University College London, London, United Kingdom; Edinburgh Migration, Ethnicity, and Health Research Group, Centre for Population Health Sciences, Institute of Population Health Sciences and Informatics, University of Edinburgh, Edinburgh, United Kingdom; 3. Department of Mathematics and Information Sciences, Faculty of Engineering and Environment, Northumbria University, Newcastle upon Tyne, United Kingdom; Health Economics and Evidence Synthesis Unit, Department of Population Health, Luxembourg Institute of Health, Strassen, Luxembourg; 4. Edinburgh Migration, Ethnicity, and Health Research Group, Centre for Population Health Sciences, Institute of Population Health Sciences and Informatics, University of Edinburgh, Edinburgh, United Kingdom; 5. Diabetes Unit, King Edward Memorial Hospital and Research Centre, Rasta Peth, Pune, Maharashtra, India; and. 6. Division of Health Sciences, Populations, Evidence, and Technologies Group, Warwick Medical School, The University of Warwick, Coventry, United Kingdom; Academic Department of Diabetes & Endocrinology, George Eliot Hospital, Nuneaton, United Kingdom p.saravanan@warwick.ac.uk.
Abstract
BACKGROUND: Vitamin B-12 and folate are micronutrients essential for normal embryogenesis. Vitamin B-12 insufficiency in pregnancy is high in certain parts of the world, such as India, and although this has been linked to low birth weight (LBW) in these populations, the relation between vitamin B-12 and birth weight (BW) elsewhere is unknown. OBJECTIVES: We performed a systematic review to assess 1) the worldwide prevalence of vitamin B-12 insufficiency in pregnancy and 2) its association with BW. DESIGN: A search of 5 electronic databases was performed to identify eligible articles. Random-effects meta-analysis was conducted according to geographic regions and pregnancy trimesters for the prevalence subreview and by categorical measures of BW. RESULTS: A total of 57 and 23 articles were included for the prevalence and BW subreviews, respectively. The pooled estimates of vitamin B-12 insufficiency were 21%, 19%, and 29% in the first, second, and third trimesters, respectively, with high rates for the Indian subcontinent and the Eastern Mediterranean. The large heterogeneity between studies was partially addressed by creating a standardized score for each study (mean vitamin B-12 insufficiency ÷ cutoff value), which internally corrected for geographic region, trimester, and assay type. Twelve of the 13 longitudinal studies included showed a decrease in mean or median vitamin B-12 across trimesters. Pooled analysis showed nonsignificantly lower maternal vitamin B-12 concentrations in LBW than in normal-BW infants and higher odds of LBW with lower vitamin B-12 values (adjusted OR: 1.70; 95% CI: 1.16, 2.50), but studies from India largely contributed to the latter. CONCLUSIONS: Our review indicates that vitamin B-12 insufficiency during pregnancy is common even in nonvegetarian populations and that concentrations of vitamin B-12 decrease from the first to the third trimester. There is no consistent association between vitamin B-12 insufficiency and LBW. However, given the long-term risks of LBW, this observation warrants further cohort studies and randomized controlled trials.
BACKGROUND:Vitamin B-12 and folate are micronutrients essential for normal embryogenesis. Vitamin B-12insufficiency in pregnancy is high in certain parts of the world, such as India, and although this has been linked to low birth weight (LBW) in these populations, the relation between vitamin B-12 and birth weight (BW) elsewhere is unknown. OBJECTIVES: We performed a systematic review to assess 1) the worldwide prevalence of vitamin B-12insufficiency in pregnancy and 2) its association with BW. DESIGN: A search of 5 electronic databases was performed to identify eligible articles. Random-effects meta-analysis was conducted according to geographic regions and pregnancy trimesters for the prevalence subreview and by categorical measures of BW. RESULTS: A total of 57 and 23 articles were included for the prevalence and BW subreviews, respectively. The pooled estimates of vitamin B-12insufficiency were 21%, 19%, and 29% in the first, second, and third trimesters, respectively, with high rates for the Indian subcontinent and the Eastern Mediterranean. The large heterogeneity between studies was partially addressed by creating a standardized score for each study (mean vitamin B-12insufficiency ÷ cutoff value), which internally corrected for geographic region, trimester, and assay type. Twelve of the 13 longitudinal studies included showed a decrease in mean or median vitamin B-12 across trimesters. Pooled analysis showed nonsignificantly lower maternal vitamin B-12 concentrations in LBW than in normal-BW infants and higher odds of LBW with lower vitamin B-12 values (adjusted OR: 1.70; 95% CI: 1.16, 2.50), but studies from India largely contributed to the latter. CONCLUSIONS: Our review indicates that vitamin B-12insufficiency during pregnancy is common even in nonvegetarian populations and that concentrations of vitamin B-12 decrease from the first to the third trimester. There is no consistent association between vitamin B-12insufficiency and LBW. However, given the long-term risks of LBW, this observation warrants further cohort studies and randomized controlled trials.
Authors: Gwendolyn Gramer; Junmin Fang-Hoffmann; Patrik Feyh; Glynis Klinke; Peter Monostori; Jürgen G Okun; Georg F Hoffmann Journal: World J Pediatr Date: 2018-06-15 Impact factor: 2.764
Authors: Tormod Rogne; Myrte J Tielemans; Mary Foong-Fong Chong; Chittaranjan S Yajnik; Ghattu V Krishnaveni; Lucilla Poston; Vincent W V Jaddoe; Eric A P Steegers; Suyog Joshi; Yap-Seng Chong; Keith M Godfrey; Fabian Yap; Raquel Yahyaoui; Tinku Thomas; Gry Hay; Marije Hogeveen; Ahmet Demir; Ponnusamy Saravanan; Eva Skovlund; Marit P Martinussen; Geir W Jacobsen; Oscar H Franco; Michael B Bracken; Kari R Risnes Journal: Am J Epidemiol Date: 2017-02-01 Impact factor: 4.897
Authors: Sara L White; Angela C Flynn; Wenneke van Weelden; Paul T Seed; Elie Antoun; Keith M Godfrey; Negusse T Kitaba; Karen A Lillycrop; Kathryn V Dalrymple; Agata Sobczyńska-Malefora; Rebecca C Painter; Lucilla Poston Journal: J Dev Orig Health Dis Date: 2021-05-11 Impact factor: 3.034