The World Health Organization defines the double burden of malnutrition (DBM) as the coexistence of undernutrition and overweight/obesity or diet-related noncommunicable disease risk, together with micronutrient deficiencies. The phenomenon is clinically relevant during pregnancy because it affects maternal and fetal outcomes and is particularly prevalent in low- and middle-income countries. This systematic review and meta-analysis aimed to quantify global prevalence estimates of DBM phenotypes among pregnant women.
The primary objective was to estimate the global prevalence of DBM in pregnant women. The review included studies reporting prevalence measures of DBM in healthy pregnant populations, considering several predefined DBM combinations: underweight with gestational diabetes mellitus (GDM), underweight with hypertension, and overweight/obesity combined with micronutrient deficiencies including anemia, vitamin D deficiency, vitamin B12 deficiency, and folate deficiency.
The review followed PRISMA recommendations. Eligible studies reported prevalence of DBM combinations in pregnant women across the gestational age range. The meta-analysis employed a random-effects model with inverse-variance weighting to pool prevalence estimates where appropriate. Risk of bias in included studies was assessed using Joanna Briggs Institute tools. The certainty of the body of evidence for outcomes was evaluated using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) framework.
A total of 62 articles met inclusion criteria, together representing 1,386,245 pregnant women. Participants in included studies ranged from 8 to 42 weeks' gestation and from 13 to 45 years of age. Figures in the article include a PRISMA-adapted flow diagram of study selection and forest plots depicting prevalence estimates for the evaluated DBM outcomes.
The review assessed the co-occurrence of underweight with gestational diabetes mellitus (GDM) and with hypertensive disorders. Prevalence estimates for underweight with GDM and underweight with hypertension were presented in the article figures and text. Specific pooled numeric prevalence results for these underweight–disease combinations are reported in the source's figures. A visual summary of the distribution of these outcomes is provided in the publication's forest plots.
Overweight/obesity coexisting with anemia was one of the most commonly reported DBM combinations. The pooled prevalence across eligible studies for overweight/obesity with anemia was 9% (95% CI: 7%–10%), derived from 18 studies. A forest plot illustrating individual study estimates and the pooled outcome is included in the publication.
The highest pooled prevalence reported in the review was for overweight/obesity coexisting with vitamin D deficiency, at 21% (95% CI: 14%–27%), based on 10 studies. The article includes a dedicated figure showing prevalence estimates for overweight/obesity and vitamin D deficiency in pregnant women.
Methodological quality assessments indicated that most included studies (66.3%) had high methodological quality according to Joanna Briggs Institute tools. Despite this, the overall certainty of the synthesized evidence for DBM prevalence outcomes was rated as low using the GRADE framework. The authors also examined publication bias visually, presenting funnel plots for outcomes.
The review highlights a substantial burden of DBM phenotypes in pregnancy, notably the concurrence of overweight/obesity with vitamin D deficiency and with anemia. These coexistences represent competing nutritional risks in the same population and have implications for antenatal screening, nutritional counseling, and supplementation strategies. The authors emphasize the need for strengthened public policies to ensure equitable access to healthy diets, evidence-based supplementation, and continuous nutritional monitoring during pregnancy, particularly in settings where DBM is most prevalent.
In this systematic review and meta-analysis of 62 studies including over 1.38 million pregnant women, overweight/obesity with vitamin D deficiency and overweight/obesity with anemia were the most prevalent double-burden phenotypes identified. The overall certainty of evidence was judged low by GRADE despite many studies demonstrating high methodological quality. The authors conclude that these findings support policies and clinical practices focused on improving dietary quality, targeted supplementation, and ongoing nutritional surveillance during pregnancy. The publication reports no conflicts of interest and is available as a free PMC article (PMCID PMC13586418). For some DBM combinations, pooled meta-analysis was not performed because too few eligible studies were available, and specific details of certain subgroup or region-specific results are reported in the full text figures and tables.