Background and objective:
The pregnant women health is a powerful indicator of a countrys health. Diseases caused by micronutrient deficiency in pregnancy represent a public health concern due to the probable risk of perinatal morbidity and mortality, and surveillance of the values of these deficiencies needs to be performed periodically by health systems for the evaluation of mother and baby health care strategies. The aim of this study was to nationally evaluate the prevalence/incidence of micronutrient deficiency in Brazilian pregnant women.

Methods:
A systematic review was performed. Nine electronic databases, including grey literature, were searched without language restrictions. Paired independent reviewers selected cross-sectional and cohort studies reporting the deficiency on vitamin A, B, C, D, E, calcium, iron, zinc, magnesium and selenium among Brazilian pregnant women, extracted data, and assessed risk of bias. A meta-analysis with a random effect model was conducted.

Results:
of the 895 references initially identified, 32 were considered eligible for this systematic review. A risk of bias was found in the key area related to the study population (target population, sampling, selection, non-responders). No one study presented data on the incidence of deficiency. In meta-analysis, the prevalence ratios ranged from 12% to 92% depending on the type of micronutrient. The overall prevalence of micronutrient deficiency was 32.8% [0.3280 (IC 95% 0.2382-0.4324)]. Anemia was the most standardized outcome among studies and its prevalence ratio was 20.0% [0.1998 (IC 95% 0.1554-0.2531)]. No pattern was found for the geographic distribution of micronutrient deficiency.

Conclusion:
The prevalence of micronutrient deficiency among Brazilian women is high. Iron deficiency was prevalent all over the country and anaemia rates justify iron supplementation as a public policy in the Brazilian Health System.