Maternal hydration and pregnancy outcomes: A literature review

Abstract

Purpose
The purpose of this study was to examine the current state of knowledge regarding the relationships between maternal hydration and pregnancy outcomes as a basis of the management of maternal hydration status during pregnancy.
Methods
A search of literature was conducted using four key electronic databases (Central Medical Journal web version , PubMed, CINAHL, and the Cochrane Library) and reference lists from: three widely used medical obstetric textbooks and selected articles. In order to integrate available knowledge, all published literature before the 5th of August 2009, written in the Japanese or English language that focused on the effects of maternal hemodynamic patterns and maternal hydration on pregnancy outcomes was sought yielding 83 articles for review. The articles were grouped by: language, type of article, and specialty, and categorized according to the research focus. Findings were systematically synthesized and discussed according to three foci of this review: 1) the relationship between maternal hydration and pregnancy outcomes; 2) recommended hydration methods for pregnant women; 3) measurement methods evaluating maternal hemodynamic patterns and hydration status in pregnancy.
Results
A number of studies reported the positive relationship between maternal hydration and increased amniotic fluid volume. However, limited research findings were noted regarding preventive or treatment effects of maternal hydration on complications in pregnancy. Although no study was found with regard to the trends of maternal fluid intake, the relationship between maternal caffeine consumption and pregnancy outcomes and the validity of a self-report survey in determining the quantity of maternal caffeine consumption were found. There were a variety of methods and measurement tools evaluating maternal hemodynamic patterns and hydration status in pregnancy. However, as a management strategy for prenatal care, optimal methods that enabled only non-invasive measurement of maternal hemodynamic patterns were not found. Also, clinical evidence for methods in maintaining maternal hydration status during pregnancy was not found.
Conclusions
The association of maternal hydration with increased amniotic fluid volume, the needs of careful examination for a type of fluids recommended for pregnant women, and bioelectrical impedance analysis as a potential non-invasive tool measuring maternal hydration status in pregnancy were found in this review. Future studies might include conducting descriptive or exploratory studies in the trends of fluid intake in relation to the pregnancy outcomes, identifying recommended hydration methods for pregnant women, and developing non-invasive and feasible measurement tools in determining physiological effects of maternal fluid intake.