Prediction of Progression to Severe Disease in Women With Late Preterm Hypertensive Disorders of Pregnancy

Abstract

Introduction If hypertensive disorders of pregnancy are diagnosed before term, the benefits of immediate delivery need to be weighed against the neonatal consequences of preterm delivery. If we are able to predict which women are at high risk of progression to severe disease, they could be targeted for delivery and maternal complications might be reduced. In addition, this may prevent unnecessary preterm births in women at low risk. Material and methods We developed a prediction model using data from the HYPITAT‐II trail, which evaluated immediate delivery vs. expectant monitoring in women with non‐severe hypertensive disorders of pregnancy between 34 and 37 weeks of gestation. Univariate and multivariate logistic regression analysis were used to identify relevant variables from clinical and laboratory parameters. The performance of the resulting prediction model was assessed by receiver operating characteristic analysis, calibration and bootstrapping, using the average predicted probabilities. Results We included 519 women, 115 (22.2%) of whom developed severe hypertensive disorders of pregnancy. The prediction model included: maternal age (odds ratio 0.92 per year), gestational age (odds ratio 0.87 per week), systolic blood pressure (odds ratio 1.05 per mmHg), the presence of chronic hypertension (odds ratio 2.4), platelet count (odds ratio 0.996), creatinine (odds ratio 1.02) and lactate dehydrogenase (odds ratio 1.003). The model showed good fit (p = 0.64), fair discrimination (area under the curve 0.76, 95% confidence interval 0.73–0.81, p < 0.001) and could stratify women in three risk groups of average, intermediate and high risk (predicted probabilities <0.22, <0.44 and >0.45, respectively). Conclusion In women with non‐severe hypertension in pregnancy near term, progression to severe disease can be predicted. This model requires external validation before it can be applied in practice.

Maternal deaths from hypertensive disorders: lessons learnt

“…Ideally, more specific advice on restrictive intravenous fluid administration could be included in the Norwegian guidelines. By solely decreasing the blood pressure and not electively inducing labor, there is a risk of covering up a more serious disease with worse outcomes (23). In 1998, the advice was to pay close attention and to continuously review the situation, but no specific advice on the timing of delivery was given.…”

“…The 2009 HYPITAT I study (11) revealed that a conservative approach to treatment and elective delivery leads to a significantly higher risk of maternal morbidity compared with an approach with induction before gestational week 37. By solely decreasing the blood pressure and not electively inducing labor, there is a risk of covering up a more serious disease with worse outcomes (23). In 2012-2014, only two women died from preeclampsia and eclampsia in the UK, which is approximately one death per 1 000 000 pregnancies (7).…”