Severe preeclampsia is a serious pregnancy complication that can lead to severe maternal and fetal outcomes, particularly when blood pressure is not adequately controlled. In France, intravenous labetalol is recommended as the first-line treatment for severe hypertension in preeclampsia. However, in clinical practice, failure to control blood pressure with labetalol is frequently observed, and the factors associated with this lack of response remain poorly understood.

The RELAPSE study is a prospective, multicenter observational study designed to identify factors associated with failure of blood pressure control with intravenous labetalol monotherapy in patients with severe preeclampsia.

The main hypothesis is that certain patient characteristics, such as maternal clinical profile, obstetric history, or biological parameters, may be associated with a higher risk of treatment failure. Identifying these factors could help clinicians better anticipate inadequate response to labetalol and adapt treatment strategies more rapidly.

Data will be collected from routine clinical care without modifying patient management. Patients will be followed from the initiation of intravenous labetalol until hospital discharge. The study will include approximately 350 patients across multiple centers.

By improving the understanding of predictors of treatment failure, this study aims to contribute to better management of severe preeclampsia and to reduce maternal and neonatal complications.

Severe preeclampsia is a serious pregnancy complication associated with maternal and fetal morbidity and mortality, mainly due to insufficient blood pressure control. Intravenous labetalol is recommended as first-line treatment, but treatment failure is frequently observed in clinical practice, and its predictors are not well established.

The RELAPSE study is a prospective, multicenter observational study aiming to assess the association between predefined patient characteristics and failure of blood pressure control with intravenous labetalol monotherapy.

Data will be collected prospectively from routine clinical care and recorded in an electronic case report form. No additional procedures will be performed, and patient management will not be modified.

Approximately 350 patients will be included across multiple centers. Participants will be followed from initiation of intravenous labetalol until hospital discharge (up to a maximum of 7 days).

The primary analysis will evaluate the association between treatment failure and predefined factors using multivariable logistic regression. Results will be expressed as odds ratios with 95% confidence intervals.

This study aims to improve the identification of patients at risk of treatment failure and contribute to better management of severe preeclampsia.

Inclusion Criteria:

• Adult patient (age ≥ 18 years)
• Pregnancy ≥ 24 weeks of gestation with one or more viable fetuses and severe preeclampsia requiring intravenous labetalol administration, either as continuous infusion (IVSE) or intravenous bolus titration

Exclusion Criteria:

• Contraindication to labetalol (asthma, chronic obstructive pulmonary disease, bradycardia, current or history of intracardiac conduction disorders, or history of hypersensitivity reaction)
• Intravenous antihypertensive treatment initiated prior to inclusion
• Patient refusal or objection to the use of her healthcare data for research purposes

Adult pregnant women with severe preeclampsia requiring intravenous labetalol as part of routine clinical care.