To investigate the associations of organic food consumption with maternal pre-pregnancy BMI, hypertension and diabetes in pregnancy, and several blood biomarkers of pregnant women.

Prospective cohort study.

Pregnant women were recruited at midwives’ practices and through channels related to consumption of food from organic origin.

Pregnant women who filled in FFQ and donated a blood sample (n 1339). Participant groups were defined based on the share of consumed organic products; to discriminate between effects of food origin and food patterns, healthy diet indicators were considered in some statistical models.

Consumption of organic food was associated with a more favourable pre-pregnancy BMI and lower prevalence of gestational diabetes. Compared with participants consuming no organic food (reference group), a marker of dairy products intake (pentadecanoic acid) and trans-fatty acids from natural origin (vaccenic and rumenic acids) were higher among participants consuming organic food (organic groups), whereas elaidic acid, a marker of the intake of trans-fatty acids found in industrially hydrogenated fats, was lower. Plasma levels of homocysteine and 25-hydroxyvitamin D were lower in the organic groups than in the reference group. Differences in pentadecanoic acid, vaccenic acid and vitamin D retained statistical significance when correcting for indicators of the healthy diet pattern associated with the consumption of organic food.

Consumption of organic food during pregnancy is associated with several health-related characteristics and blood biomarkers. Part of the observed associations is explained by food patterns accompanying the consumption of organic food.