Impact of Pre-Pregnancy BMI on B Vitamin and Inflammatory Status in Early Pregnancy: An Observational Cohort Study

Abstract

Maternal nutrition and inflammation have been suggested as mediators in the development of various adverse pregnancy outcomes associated with maternal obesity. We have investigated the relation between pre-pregnancy BMI, B vitamin status, and inflammatory markers in a group of healthy pregnant women. Cobalamin, folate, pyridoxal 5′-phosphate, and riboflavin; and the metabolic markers homocysteine, methylmalonic acid, and 3-hydroxykynurenine/xanthurenic acid ratio (HK/XA); and markers of cellular inflammation, neopterin and kynurenine/tryptophan ratio (KTR) were determined in pregnancy week 18 and related to pre-pregnancy body mass index (BMI), in 2797 women from the Norwegian Mother and Child Cohort Study (MoBa). Pre-pregnancy BMI was inversely related to folate, cobalamin, pyridoxal 5′-phosphate (PLP), and riboflavin (p < 0.001), and associated with increased neopterin and KTR levels (p < 0.001). Inflammation seemed to be an independent predictor of low vitamin B6 status, as verified by low PLP and high HK/XA ratio. A high pre-pregnancy BMI is a risk factor for low B vitamin status and increased cellular inflammation. As an optimal micronutrient status is vital for normal fetal development, the observed lower B vitamin levels may contribute to adverse pregnancy outcomes associated with maternal obesity and B vitamin status should be assessed in women with high BMI before they get pregnant.

Vitamin B12 deficiency and altered one-carbon metabolites in early pregnancy is associated with maternal obesity and dyslipidaemia

“…The regression analysis in cohort 1, after correcting for multiple confounders, we found that B12 is independently associated with BMI whereas in cohort 2, in addition to B12, social deprivation was also associated with BMI. The association between BMI and B12 has been shown in other studies in pregnant women 15,16,17 but also in adolescents 14 and in women of childbearing age 28 . In addition, B12 deficiency may be causally related to dysglycaemia 9 .…”

“…In children and adolescents, increase in BMI 13 and IR 14 have been associated with low B12 levels. Furthermore, studies in early pregnancy have focussed on association between lower maternal micronutrient status (B12, folate, iron) with pre-pregnancy overweight and obesity in mothers 15,16,17 , with lower micronutrients in low-birth weight infants 18 and with higher BMI and heart rate in children at age 5-6 19 . Our in vitro studies have shown that B12 deficiency in adipocytes altered DNA methylation levels 2 of the transcription factors of lipid regulation 2 and the adipose derived miRNAs targeting IR 3 thereby suggesting that B12 deficiency dysregulates epigenetic mechanisms.…”

An epigenetic association of malformations, adverse reproductive outcomes, and fetal origins hypothesis related effects

“…Folate connections to the association are also supported by maternal obesity effects. Since serum folate levels are inversely related to pre-pregnancy body mass [131], association findings would be expected, and do occur. Despite late macrosomia with obesity-related metabolic disturbances, there is excess growth restriction early on [132], as well as increases in limb reductions; anorectal, renal, and cardiovascular anomalies [133][134][135]; fertility issues [136]; prematurity; early losses and stillbirth; and possibly perinatal difficulties [137].…”

Association of Maternal Prepregnancy Body Mass Index With Fetal Growth and Neonatal Thalamic Brain Connectivity Among Adolescent and Young Women

“…A complete distribution of maternal BMI is needed to fully characterize these possible fetal outcomes. Many prior studies have not been able to disentangle the influence of maternal BMI from cooccurring health-related (eg, diabetes, hypertension) factors, 16 which is important to help inform preventive efforts.…”