Furosemide vs Placebo in Severe Preeclampsia Postpartum

Total hours from first study dose (administered at 12 hours postpartum) to hospital discharge. Discharge is defined as achievement and maintenance of blood pressure <140/90 mmHg for at least 24 consecutive hours without need for rescue antihypertensive medication. Rescue medication is defined as any extra dose of labetalol or hydralazine administered for hypertensive crisis (blood pressure >160/110 mmHg). Time is measured in hours from the moment of first dose (hour 0) until the moment discharge orders are written. If a patient requires rescue medication, the clock does not reset; discharge criteria must still be met for 24 hours without rescue.

Percentage of participants in each arm who require at least one dose of rescue antihypertensive medication (labetalol or hydralazine) during hospitalization. Rescue medication is indicated for hypertensive crisis defined as systolic blood pressure >160 mmHg or diastolic blood pressure >110 mmHg at any time after study drug administration. The proportion is calculated as number of participants receiving any rescue dose divided by total participants in the arm.

Absolute difference between baseline weight (measured at 12 hours postpartum, immediately before first study dose) and weight at hospital discharge (measured on the morning of discharge day). Weight is measured in kilograms using the same calibrated scale for each participant. Delta weight is calculated as baseline weight minus discharge weight. A positive value indicates weight loss.

Proportion of participants in each arm developing hypokalemia, defined as serum potassium <3.0 mEq/L. Blood sample is drawn at 48 hours after first study dose or at hospital discharge (whichever occurs first). Hypokalemia is considered an adverse event of special interest given furosemide's mechanism of action as a loop diuretic. Severe hypokalemia (<2.5 mEq/L) triggers unblinding and protocol-defined management.

Change in serum creatinine from baseline to follow-up measurement. Baseline creatinine is measured at enrollment (12 hours postpartum, before first dose). Follow-up creatinine is measured at 48 hours after first dose or at hospital discharge (whichever occurs first). Renal deterioration is defined as an increase in serum creatinine of ≥0.3 mg/dL from baseline or a percentage increase of ≥50%. Mean change (absolute and percentage) is compared between groups.

Incidence of spontaneously reported adverse events potentially related to furosemide, including dizziness/orthostatic hypotension, muscle cramps, and palpitations. Participants are asked daily "Have you experienced any unusual symptoms since the last dose?" Responses are recorded regardless of suspected relationship to study drug. Severity is graded as mild (minimal or no treatment needed), moderate (some interference with daily activities), or severe (significant interference).

Proportion of participants discharged from the hospital without requiring any maintenance antihypertensive medication. Maintenance antihypertensives are defined as scheduled oral medications (not rescue doses) intended to control blood pressure after discharge. Participants who require continued antihypertensive therapy at discharge (any dose, any agent) are considered not achieving antihypertensive-free discharge.