Oxidative Stress and Preterm Birth: An Integrative Review

Background: A variety of methods and measures have been used to quantify oxidative stress in clinical studies related to preterm birth (PTB), and studies have reported conflicting findings. No integrative reviews have been conducted. Objective: To describe specific molecules used as markers of oxidative stress and methods to measure these molecules and to review the literature for associations between oxidative stress and PTB specific to these molecules. Method: Systematic literature searches were conducted in June 2015 and updated in 2017 in databases from the Biomedical Reference Collection: Basic Edition, including MEDLINE and clinicaltrials.gov. Articles were included if they described original research published after 2009 and compared PTB or preterm premature rupture of membranes with term birth (TB). Results: Abstracts (n = 3,107) were reviewed for inclusion/exclusion criteria. Of these, 308 were full-text reviewed, and 30 articles were included in this review. All were identified as nonexperimental. The most common measurements of oxidative stress were quantification of total oxidant or antioxidant status or lipid peroxidation. Studies measuring reactive oxygen species or by-products of oxidative stress reported higher levels of these molecules for preterm specimens compared to TB specimens. Studies measuring antioxidants reported lower levels for these molecules in PTB specimens. Few of the studies had inconclusive findings. Discussion: Findings suggest that an imbalance between oxidants and antioxidants may be associated with PTB. The measurements and findings to date limit interpretation and understanding. Research using multidimensional methods and multidisciplinary teams are necessary to advance research and practice.