Association between pre-pregnancy weight status and maternal micronutrient status in early pregnancy

Objective: Inadequate maternal micronutrient status during pregnancy can lead to short- and long-term health risks for mother and offspring. The present study investigated the association between pre-pregnancy weight status and micronutrient status during pregnancy. Design: Maternal blood samples were collected during early pregnancy (median 13, interquartile range 12-15 weeks) and were assayed for serum folate, ferritin, Fe and vitamin B-12. Regression modelling was used to assess the association between pre-pregnancy underweight, normal weight, overweight and obesity, and micronutrient levels, as well as the odds for deficiencies. Setting: The Amsterdam Born Children and their Development (ABCD) study, the Netherlands. Subjects: Women with singleton pregnancies without diabetes (n 4243). Results: After adjustment for covariates, overweight women and obese women had lower (beta; 95% CI) folate (-1.2; -2.2, -0.2 and -2.3; -4.0, -0.7 nmol/1, respectively) and Fe (-1.7; -2.3, -14 and -3.6; -4.7, -2.6 mu mol/1, respectively) levels than women with normal weight. Furthermore, overweight women had 6% (95% CI -9, -3%) and obese women had 15% (-19, -10%), lower vitamin B-12 levels, and obese women had 19% (6, 32%) higher ferritin levels, than normal-weight women. Obese women had higher odds (OR; 95% CI) for folate deficiency (2.03; 1.35, 3.06), Fe deficiency (3-26; 2.09, 5.08) and vitamin B-12 deficiency (2.05; 1.41, 2.99) than women with normal weight. Underweight was not associated with micronutrient status. Conclusions: During early pregnancy, women with pre-pregnancy overweight and obesity had lower serum folate, Fe and vitamin B-12 status. This resulted in increased risk of serum folate, Fe and vitamin B-12 deficiencies in women with obesity.