Recent ACC/AHA hypertension (HTN) guidelines reclassified blood pressure (BP) previously regarded as ‘normal.’ It is unknown if these new cutoffs can be used to better risk-stratify pregnant women. We sought to evaluate the association between initial pregnancy BP and placentally-mediated pregnancy complications. Retrospective cohort of women delivering a singleton, non-anomalous pregnancy at a single tertiary center, 2014-2019. Women with ≥ 1 BP < 20 weeks’ gestational age (GA) were included; each woman was classified as BP1-normal (< 120/< 80), BP2-elevated (120-129 /< 80), BP3-stage1 HTN (130-139/80-89), BP4-stage2 HTN (140-159/90-109), or BP5-severe (≥160/ ≥110) using their earliest recorded pregnancy BP. The primary outcome was gestational HTN (BP ≥ 140/90 without prior CHTN dx) ± preeclampsia (PREE; BP ≥ 140/90 plus proteinuria regardless of prior CHTN dx). Secondary outcomes were delivery GA, PTB < 37 & < 34 weeks, and SGA (birthweight < 10% for GA, gender). Statistical analysis was by chi2, ANOVA, and logistic regression. 9,038 women met inclusion criteria; 49.0% BP1, 18.6% BP2, 21.0% BP3, 10.1% BP4, and 1.4% BP5. As initial BP class increased, women were more likely to be black, diabetic, and obese pre-pregnancy (Table 1). Further, as the initial BP class increased, the rate of gestational HTN ± PREE and prematurity increased, and delivery GA decreased (Table 1). In regression models, these trends persisted; the most significant relationship was noted between BP class and gestational HTN ± PREE (Figure 1). In a sensitivity analysis excluding 1,521 women with a prior CHTN diagnosis, effects were more pronounced, as BP class remained associated with an increased odds of gestational HTN ± PREE [BP2-OR 1.88 (95% CI 1.52-2.31), BP3-OR 2.99 (95% CI 2.47-3.62), BP4-OR 3.35 (95% CI 2.57-4.38), BP5-OR 5.15 (95% CI 2.43-10.91)]. Women with early pregnancy BP meeting revised ACA/AHA classifications for elevated and stage 1 HTN have increased odds of hypertensive disorders of pregnancy, at a rate similar to women with early pregnancy BP ≥140/90.View Large Image Figure ViewerDownload Hi-res image Download (PPT)