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 B12. 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 (ß; 95 % CI) folate (-1·2; -2·2, -0·2 and -2·3; -4·0, -0·7 nmol/l, respectively) and Fe (-1·7; -2·3, -1·1 and -3·6; -4·7, -2·6 µmol/l, 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 B12 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 B12 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 B12 status. This resulted in increased risk of serum folate, Fe and vitamin B12 deficiencies in women with obesity.