Stage 1 hypertension defined by the 2017 ACC/AHA guidelines and neonatal outcomes: Systematic review and meta-analysis

In 2017, the American College of Cardiology/ American Heart Association (ACC/AHA) guidelines redefined the threshold of high blood pressure (BP) for non-pregnant adults. Several studies aimed to determine whether lowering these thresholds should be considered for pregnancies to prevent poor neonatal outcomes, but the results were inconclusive.We perform a systematic review and meta-analysis to evaluate the association between BP groups defined by the 2017 ACC/AHA guidelines and pregnancy outcomes. Relevant literature was searched in PubMed, Google Scholar, Embase, and Web of Science up to 18 May 2021.Sixteen eligible studies from twelve articles with a total of 303,131 pregnancies were identified, encompassing 233,084, 20,859, 39,379 individuals with normal BP, elevated BP, and stage 1 hypertension, respectively. When compared with normal BP, the combined odds ratio (95% confidence interval) of elevated BP for adverse pregnancy outcomes was not significant; whereas, that of stage 1 hypertension were 1.25 (1.13-1.39), 1.16 (1.03-1.31), 1.50 (1.28-1.77) and 1.12 (1.00-1.25) for preterm delivery, small for gestational age, low birth weight, and early-term delivery, respectively.Our results indicated that stage 1 hypertension increased the risk of poor neonatal outcomes, highlighting the importance of recognition of stage 1 hypertension as a risk indicator for poor pregnancy outcomes.