What is the question?

• The question is: What is the relationship between dietary patterns consumed during pregnancy and risk of hypertensive disorders of pregnancy? The population or life-stage of interest for this question is pregnancy.

Why was this question asked? 

• This systematic review was conducted by the 2025 Dietary Guidelines Advisory Committee as part of the process to develop the Dietary Guidelines for Americans, 2025-2030. 

How was this question answered? 

• The Committee conducted a systematic review to answer this question with support from the USDA Nutrition Evidence Systematic Review team. This review updated an existing review that was conducted as part of the Pregnancy and Birth to 24 Months Project. 

What is the answer to the question? 

• A conclusion statement cannot be drawn about the relationship between dietary patterns consumed during pregnancy and risk of hypertensive disorders of pregnancy because of substantial concerns with consistency, directness, and precision in the body of evidence. 

H2 How up-to-date is this systematic review? 

• The conclusion statement from this review is based on articles published between January 1980 and May 2023.

Background 

• This systematic review was conducted by the 2025 Dietary Guidelines Advisory Committee as part of the process to develop the Dietary Guidelines for Americans, 2025-2030. The U.S. Departments of Health and Human Services (HHS) and Agriculture (USDA) appointed the 2025 Dietary Guidelines Advisory Committee (Committee) in January 2023 to review evidence on high priority scientific questions related to diet and health. Their review forms the basis of their independent, science-based advice and recommendations to HHS and USDA, which is considered as the Departments develop the next edition of the Dietary Guidelines. As part of that process, the Committee conducted a systematic review with support from the USDA Nutrition Evidence Systematic Review (NESR) team to answer the following question: What is the relationship between dietary patterns consumed during pregnancy and risk of hypertensive disorders of pregnancy? This review is an update to an existing review that was conducted as part of the Pregnancy and Birth to 24 Months Project. 

Methods 

• The Committee conducted a systematic review using the methodology of the USDA NESR team. The Committee first developed a protocol. The intervention/exposure was dietary patterns consumed during pregnancy, the comparators are different dietary patterns or different levels of adherence to/consumption of the same dietary pattern, and the outcomes were blood pressure (systolic, diastolic), protein in the urine (proteinuria), eclampsia, preeclampsia, and gestational hypertension during pregnancy. Additional inclusion criteria were established for the following study characteristics: a) use randomized or non-randomized controlled trial, prospective or retrospective cohort, or nested case-control study designs, b) be published in English in peer-reviewed journals, c) be from countries classified as high or very high on the Human Development Index, and d) enroll participants with a range of health statuses. The review excluded studies that exclusively enrolled participants with a disease or that did not control for at least 1 of the key confounders listed in the analytic framework. 
• NESR librarians conducted a literature search in PubMed, Embase, CINAHL, and Cochrane to identify articles published between January 2017 and May 2023. Two NESR analysts independently screened all electronic results and the reference lists of included articles based on the pre-determined criteria. The results of this search were combined with included articles from the existing review. 
• NESR analysts extracted data, from each included article, with a second analyst verifying accuracy of the extraction. Two NESR analysts independently conducted a formal risk of bias assessment, by study design, for each included article, then reconciled any differences in the assessment. The Committee qualitatively synthesized the evidence from all included articles identified in the updated literature search and from the existing review, according to the synthesis plan, with attention given to the overarching themes or key concepts from the findings, similarities and differences between studies, and factors that may have affected the results. The Committee developed a conclusion statement and graded the strength of evidence based on its consistency, precision, risk of bias, directness and generalizability. 

Results 

Dietary patterns and hypertensive disorders of pregnancy

Conclusion statement and grade

• A conclusion statement cannot be drawn about the relationship between dietary patterns consumed during pregnancy and risk of hypertensive disorders of pregnancy because of substantial concerns with consistency, directness, and precision in the body of evidence. (Grade: Grade Not Assignable) 

Summary of the evidence 

• Thirty-one articles met the inclusion criteria for this review. Twenty-three were prospective cohort studies, 8 were randomized controlled trials, and 1 was a non-randomized controlled trial.
• The direction of results and size of effects were too different across studies to adequately compare and synthesize. 
• None of the intervention studies were designed to directly examine the relationship of interest and only a few studies noted having sufficient power to detect differences between groups in the relatively rare HDP outcome. 
• In the future, researchers should include populations representative of the U.S. population, conduct well-designed and sufficiently powered trials, account for key confounding factors, administer validated dietary assessments early in pregnancy, and evaluate dietary patterns against existing indices of dietary quality.

Download Now 

Suggested citation: Byrd-Bredbenner C, Abrams SA, Andres A, Deierlein A, Eicher-Miller HA, Fisher JO, Odoms-Young A, Palacios C, Scinto-Madonich S, Nevins J, Higgins M, Raghavan R, Butera G, Terry N, Obbagy J. Dietary Patterns Consumed During Pregnancy and Risk of Hypertensive Disorders of Pregnancy. November 2024. U.S. Department of Agriculture, Food and Nutrition Service, Center for Nutrition Policy and Promotion, Nutrition Evidence Systematic Review. Available at: https://doi.org/10.52570/NESR.DGAC2025.SR08