Serum vitamin B12Nutrition library
LibraryBlood markersVitamins & minerals
Serum vitamin B12
Serum B12 measures circulating cobalamin — essential for methylation, myelination, and red-cell maturation.
Borderline B12 is common on plant-forward diets or with metformin use. Functional deficiency may show before serum falls if holotranscobalamin is low.
How to read it
If serum is borderline, check holotranscobalamin and homocysteine. Oral or sublingual B12 often corrects dietary gaps.
Linked nutrient: Vitamin B12 · calibrates store dynamics in Trends when logged.
Trimester context
| Stage | For the mother | For the baby |
|---|---|---|
| First trimester | Supports early neurological and haematopoietic demands. | Fetal neural tissue is B12-sensitive. |
| Second trimester | Rising blood volume increases demand. | Myelination accelerates in the second half of pregnancy. |
| Third trimester | Deficiency risks fatigue, neuropathy, and elevated homocysteine. | Adequate maternal B12 supports neonatal stores. |
Connections
See also
- Vitamin B12nutrient