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

Background 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. Methods 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. Results 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. Conclusion 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.