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430: The American College of Cardiology/American Heart Association new blood pressure criteria and associated neonatal outcomes

      Objective

      The blood pressure cut off for diagnosis of preeclampsia has historically been based on hypertension criteria defined by the American College of Cardiology (ACC) and American Heart Association (AHA). Recently, they decreased their criteria, defining stage 1 hypertension as a blood pressure greater than 130/80, raising the question as to whether the new definition should be adopted in pregnancy. We aimed to evaluate whether women meeting this new blood pressure threshold at the time of admission for labor had an increased risk for adverse neonatal outcomes.

      Study Design

      This is a retrospective cohort study of all women with singleton pregnancies admitted for delivery at a tertiary care center from 2004-2014. Using blood pressure on admission, women were classified into three groups: 1) normotensive if their blood pressure was <130/80, 2) stage 1 hypertension if their blood pressure was 130-139/80-89, or 3) overt hypertension if their blood pressure was >140/90. Patients with preexisting chronic hypertension were excluded. The risk of small for gestational age (SGA), 5-minute Apgar score <7, and higher level nursery admission were examined across groups. Baseline characteristics were compared using chi square and ANOVA. Neonatal outcomes were compared with the normotensive group as the reference using logistic regression to control for confounders.

      Results

      28,993 women met inclusion criteria, 14,685 (51%) were classified as normotensive, 7,828 (27%) were classified as stage 1 hypertension, and 6,480 (22%) were classified as having overt hypertension. Women with hypertensive disorders were more likely to be older, nulliparous, African American, obese, and have pre-gestational diabetes. Incidence of SGA increased across the three groups (12.5%, 13.1%, 15.7%) but was only statistically significant for women with overt hypertension (aOR 1.56, 95% CI 1.02-1.31). The risk of Apgar <7 at 5 minutes and higher order nursery admission was significantly increased in the overt hypertension group only (Table).

      Conclusion

      The impact of lowering the diagnostic criteria for hypertension in pregnancy according to the new ACC/AHA criteria has unknown impact for obstetric patients. These results suggest that rates of SGA and immediate neonatal outcomes may be similar among normotensive patients and those with blood pressure elevations of 130- 139/80-89. Further research is required before diagnostic criteria for hypertension are lowered in pregnancy.
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