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NCT Number: NCT07547046

Factors Associated With Blood Pressure Control Failure to Intravenous Labetalol in Severe Preeclampsia

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.

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Key information

Conditions

Severe Preeclampsia Female Urogenital Diseases and Pregnancy Complications Hypertension, Pregnancy-Induced Pre-Eclampsia Pregnancy Complications Urogenital Diseases

Age range

18 year and older

Sex eligibility

Female

Study type

Observational

Primary location

CHU Bordeaux, Bordeaux, France

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About this study

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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Primary outcomes

  1. Failure of blood pressure control with intravenous labetalol monotherapy

    Time frame: During the first hour following initiation of intravenous labetalol administration

    Composite outcome defined as failure to achieve blood pressure control with intravenous labetalol monotherapy in patients with severe preeclampsia. Failure is defined by the occurrence of at least one of the following: addition or switch to another antihypertensive treatment; persistence of severe hypertension after four intravenous labetalol boluses; persistence of hypertension despite continuous intravenous labetalol infusion at the maximum dose of 1 mg/kg/h; or occurrence of a complication attributable to inadequate blood pressure control (e.g., stroke, eclampsia, pulmonary edema, maternal or neonatal death).

Secondary outcomes

  1. Adverse effects related to intravenous labetalol

    Time frame: During the first hour following initiation of intravenous labetalol administration

    Occurrence of adverse events potentially related to labetalol administration, including allergic reactions, bronchospasm, and neonatal hypoglycemia.

  2. Safety of intravenous labetalol administration

    Time frame: During the first hour following initiation of intravenous labetalol administration

    Occurrence of safety events defined as maternal hypotension (systolic blood pressure < 90 mmHg, diastolic blood pressure < 60 mmHg, or mean arterial pressure < 65 mmHg) and/or maternal bradycardia (heart rate < 50 beats per minute).

  3. Maternal and fetal morbidity and mortality

    Time frame: From initiation of intravenous labetalol treatment until hospital discharge (up to 7 days)

    Occurrence of maternal and fetal complications related to severe preeclampsia or inadequate blood pressure control, including stroke, eclampsia, intracranial hemorrhage, placental abruption, intrauterine fetal death, posterior reversible encephalopathy syndrome, reversible cerebral vasoconstriction syndrome, pulmonary edema, maternal death, or neonatal death.

  4. Predictive dose of intravenous labetalol failure

    Time frame: From initiation of intravenous labetalol treatment until treatment failure or blood pressure control, assessed during hospitalization (up to 7 days)

    Total dose of intravenous labetalol administered prior to meeting criteria for treatment failure.

  5. Emergency cesarean delivery

    Time frame: From initiation of intravenous labetalol treatment until hospital discharge (up to 7 days)

    Occurrence of emergency cesarean section during hospitalization.

Study contacts

Contact information is provided by the study sponsor or research team.

Agnès LE GOUEZ-DIVISIA

CONTACT

[email protected]

1 45 37 42 73 ext. +33

Sponsors and collaborators

Lead sponsor

Assistance Publique - Hôpitaux de Paris

Other

Registry information

Official study title

Assessment of the Association Between Predefined Factors and Response or Failure of Blood Pressure Control With Intravenous Labetalol Monotherapy in Severe Preeclampsia: a Multicenter Observational Study

Acronym: RELAPSE

Important dates

Study start
2026
Primary completion
2026
Study completion
2026
First posted
Apr 23, 2026
Registry last updated
Apr 23, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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