Beyond clinic readings: Twenty‐four hour ambulatory blood pressure monitoring profiling enhances preterm delivery risk stratification in hypertensive pregnancies

OBJECTIVE: Hypertensive disorders of pregnancy (HDP) cause significant perinatal morbidity. We developed a nomogram predicting preterm delivery risk using pre-delivery 24-h ambulatory blood pressure monitoring (ABPM) and clinical factors. METHODS: HDP patients undergoing ABPM within 1 month pre-delivery were enrolled. Multivariable logistic regression identified preterm labor predictors. Nomogram performance was validated via receiver operating characteristic (ROC) analysis, calibration curves, and decision curve analysis (DCA). RESULTS: Compared with dipper and non-dipper types, the reverse dipper-type on 24-h ABPM was significantly associated with higher rates of preterm labor (55, 56.1% vs. 11, 30.6% vs. 75, 46.3%, respectively; P = 0.028) and cesarean delivery (91, 92.9% vs. 28, 77.8% vs. 145, 89.5%, respectively; P = 0.044). Multivariable analysis identified pregnancy weight gain (odds ratio [OR] 0.88, 95% confidence interval [CI]: 0.83-0.93, P < 0.001), gravidity (OR 3.60, 95% CI: 1.69-7.66, P = 0.001), assisted reproductive technology use (OR 3.99, 95% CI: 1.29-12.34, P = 0.016), nighttime systolic blood pressure load (OR 1.02, 95% CI: 1.00-1.04, P = 0.026), nighttime heart rate (OR 1.06, 95% CI: 1.03-1.09, P < 0.001), urine protein (OR 3.07, 95% CI: 1.27-7.45, P = 0.013), and urine output (OR 1.01, 95% CI: 1.00-1.01, P = 0.003) as independent risk factors for preterm labor in women with HDP. These seven variables were incorporated into a nomogram prediction model. The discriminative ability of the model was assessed using a ROC curve, yielding an AUC of 0.852. The DCA indicated a favorable net benefit and clinical utility for the model. CONCLUSION: This validated nomogram improves preterm risk stratification in HDP using pre-delivery ABPM parameters.