Association between abnormal maternal serum levels of vitamin B12 and preeclampsia: a systematic review and meta-analysis

Context: Some evidence has shown an association between maternal vitamin B12 levels and the development of preeclampsia in pregnant women, but the relationship between preeclampsia and vitamin B-12 is not clear. Objective: The aim of this systematic review was to compare serum vitamin B-12 levels in women with preeclampsia with those in normotensive pregnant women. Data Sources: The PubMed/MEDLINE, Scopus, and Web of Science databases were searched up to August 2019, along with the reference lists of included articles. Study Selection: The literature was searched for observational studies that investigated vitamin B-12 levels in women with preeclampsia. Data Extraction: Data were extracted independently by 2 authors. Data were pooled using a randomeffects model. Results: Vitamin B-12 levels in women with preeclampsia were significantly lower than those in healthy women (mean, similar to 15.24 pg/mL; 95%CI, similar to 27.52 to similar to 2.954; P< 0.015), but heterogeneity between studies was high (I-2 = 97.8%; P = 0.0103). Subgroup analyses based on folic acid supplementation, homocysteine concentrations, and gestational age at the time of sampling for vitamin B-12 assessment did not identify the sources of heterogeneity. Conclusions: Women with preeclampsia had significantly lower vitamin B-12 concentrations than normotensive pregnant women.

Automated summary

The study found that women with preeclampsia had significantly lower levels of vitamin B12 compared to normotensive pregnant women. Subgroup analyses did not identify the sources of heterogeneity.