Vitamin B <sub>12</sub> : dietary intake, supplement use and serum concentrations in a cohort of Canadian pregnant women and in umbilical cord blood (135.7)
Bibliographic record
Abstract
Optimal maternal intake and blood levels of vitamin B 12 play an important role in fetal development and in health and disease of the offspring. Nonetheless, there is a paucity of data of intake and blood levels of B 12 in Canadian pregnant women and in cord blood. We assessed dietary and supplemental intakes using a food frequency questionnaire and serum B 12 levels in pregnant women between 12‐16 wks gestation (n=342) and at parturition (n=292) and in cord blood (n=259). Mean intake of dietary B 12 was 5.2 ± 3.1 µg/d and 5.2 ± 2.7 µg/d in early and late pregnancy, respectively (RDA= 2.6 µg/d). Additionally, 88% reported using a B 12 ‐containing supplement (usual amount 2.6 µg) during early pregnancy and 83% continued supplement use in late pregnancy. Median serum B 12 concentrations in early pregnancy, at parturition and in cord blood were 220 (inner quartile range: 167,289) pmol/L, 167 (131,208) pmol/L and 314 (223,466) pmol/L, respectively. All participants had plasma homocysteine levels in the normal range (<13 µmol/L) during pregnancy. The prevalence of suboptimal serum B 12 levels (<148 pmol/L) was observed in 17% and 36% of women in early and late pregnancy, respectively. Our data indicate that suboptimal B 12 status, assessed by serum B 12 levels, exists in Canadian women during pregnancy despite adequate B 12 intakes from diet and supplement use. Whether the observed low maternal B 12 levels are functionally significant and impact maternal and fetal health outcomes requires further investigation.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.003 |
| Science and technology studies | 0.002 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".