This randomized, double-blind, placebo-controlled trial evaluates whether oral furosemide 40 mg, initiated 12 hours postpartum, reduces hospital length of stay compared to placebo (folic acid 5 mg) in postpartum women with severe preeclampsia. Secondary outcomes include need for rescue antihypertensive medications, weight reduction, and metabolic safety (hypokalemia, renal function). A total of 186 participants (93 per arm) will be enrolled across two hospitals in Honduras.

Background: Preeclampsia is a leading cause of maternal morbidity worldwide. Postpartum management focuses on blood pressure control and resolution of endothelial dysfunction. Loop diuretics like furosemide may accelerate normalization of intravascular volume and blood pressure, potentially reducing hospital stay.

Hypothesis: Furosemide 40 mg oral once daily reduces total postpartum hospital hours compared to placebo.

Study Design: Phase 2, randomized, double-blind, placebo-controlled, parallel-group trial.

Setting: Hospital Materno Infantil and Instituto Hondureño de Seguridad Social, Honduras.

Interventions:

Experimental: Furosemide 40 mg oral every 24 hours, starting at 12 hours postpartum, continued until hospital discharge.

Placebo: Folic acid 5 mg oral (identical appearance, packaging, and administration schedule).

Blinding: Double-blind. Only an independent pharmacist knows group assignment. Blinding is broken only for life-threatening adverse events.

Follow-up: Entirely inpatient, from enrollment (12 hours postpartum) until hospital discharge (estimated 3-7 days).

Inclusion Criteria:

• Signed informed consent (assent for minors 14-17 years with parental/guardian consent)
• Confirmed severe preeclampsia (BP ≥160/110 mmHg, or lower BP with thrombocytopenia, hepatic dysfunction, renal insufficiency, pulmonary edema, or cerebral/visual symptoms)
• Postpartum (12-24 hours after delivery, vaginal or cesarean)
• Hemodynamically stable (no vasopressors for ≥6 hours)
• Preserved diuresis (>30 mL/hour for ≥6 hours)
• Serum creatinine <0.8 mg/dL

Exclusion Criteria:

• Current or chronic diuretic use (before or during pregnancy)
• Known allergy to sulfonamides or furosemide
• Active febrile illness
• Known chronic kidney disease (eGFR <60 mL/min/1.73m²)
• Participation in another interventional trial
• Pregnancy (current - not applicable postpartum, but excludes undiagnosed concurrent pregnancy)

De-identified individual participant data (IPD) for all primary and secondary outcome measures will be shared publicly via Mendeley Data repository. The dataset will include: participant demographics, baseline clinical characteristics, primary outcome (hospital length of stay in hours), secondary outcomes (rescue medication requirement, weight change, laboratory values including potassium and creatinine, adverse events, discharge antihypertensive status), and protocol deviations. Data will be anonymized with no direct identifiers (name, medical record number, date of birth). Each participant will be identified by a unique study code only.

Timeline: Data will be deposited within 12 months after primary results publication. The repository link will be included in the primary publication and in this ClinicalTrials.gov record when available.

Supporting documents also available via Mendeley Data: Study protocol (v1.0), Statistical Analysis Plan (SAP), and blank informed consent form

Available starting 12 months after primary results publication. Available for 5 years thereafter.

No registration or authorization required for download. Data will be under a CC BY-NC 4.0 license (Creative Commons Attribution-NonCommercial 4.0 International), allowing other researchers to use, share, and adapt the data for non-commercial purposes with proper attribution.

1. Participants - Patients receive identical opaque white bottles labeled only with "Estudio FURO-PE, Paciente #XXX" and have no knowledge of whether the contents are furosemide 40 mg or placebo (folic acid 5 mg).
2. Investigators (Principal Investigators and Sub-investigators) - All clinical staff responsible for enrollment, outcome assessment, and discharge decisions are unaware of group assignment.
3. Outcome assessors - The same research team members who evaluate blood pressure, laboratory results, and discharge criteria are masked.
4. Statistician - The data analyst will receive a dataset with group codes (A/B) and will not know which code corresponds to furosemide or placebo until final database lock.

Only one independent, unblinded person (a designated pharmacist not involved in patient care or outcome assessment) knows the allocation. This person prepares and labels all bottles but does not interact with participants or investigators.