Effect of Acetaminophen on Postpartum Blood Pressure Control in Preeclampsia With Severe Features

NSAIDs, specifically cyclo-oxygenase (COX) inhibitors, are known to increase blood pressure over time in non-pregnant adults, but the effect of COX-inhibitors on blood pressure in the setting of preeclampsia have not been well studied. This study aims to assess the effect of avoiding COX-inhibitors on postpartum blood pressure control among women diagnosed with preeclampsia with severe features. Eligible women will be randomized to receive either acetaminophen or ibuprofen for postpartum pain control. Both agents are first line therapies for pain control although ibuprofen has better pain control than acetaminophen. The primary outcome will be duration of postpartum severe-range hypertension.

The proposed study is a randomized, controlled, double-masked trial comparing the effect of postpartum acetaminophen and ibuprofen on blood pressure among women with preeclampsia. Study participants will be randomized to receive either acetaminophen or ibuprofen for mild postpartum pain control. Study participants, study personnel and providers will be blinded to randomization status of study participants. Potential study participants will be enrolled when they are diagnosed with a severe hypertensive disorder of pregnancy. This will usually occur prior to delivery, but may occur up to 6 hours after delivery. Patients diagnosed with preeclampsia without severe features will also be approached and enrolled at the time of diagnosis in anticipation for possible progression to preeclampsia with severe features. Once enrolled, study participants will not be randomized until delivery, at which time they will be randomized to receive either acetaminophen or ibuprofen for mild postpartum pain. Both groups will have available oxycodone for moderate to severe pain, per our routine. Study group allocation will only be known by the investigational pharmacy. The ibuprofen and acetaminophen will be made to appear identical to each other and will be unmarked through encapsulation. Block randomization will be used to ensure equal allocation to the two study arms. For the duration of study participation, study participants will undergo postpartum monitoring with vital sign measurements (including blood pressure) every 4 hours, pain assessment with each administration of study medication, as well as daily evaluation of laboratory studies until they have normalized to the satisfaction of their provider. Study participants will receive the study drug every 6 hours from the time of delivery until hospital discharge, unless they refuse. Study participation will be complete upon hospital discharge. Study participants will be contacted by a study team member 6 weeks after delivery to ask about any additional complications or symptoms requiring visits to the emergency department or hospital readmission. Descriptive factors and clinical outcomes will be extracted from the medical record and de-identified by study personnel during each day of study participation.

Study participants randomized to the acetaminophen group will receive 650mg of acetaminophen orally every 6 hours during their postpartum hospital stay.

Study participants randomized to the ibuprofen group will receive 600mg of ibuprofen orally every 6 hours during their postpartum hospital stay.

computed mean arterial pressure using all measured blood pressures during postpartum hospitalization, stratified by postpartum day (1, 2, 3, etc.)

mean total number of severe range blood pressure (defined as SBP >160mmGh or DBP >110mmHg) measurements in each study arm

Proportion in each arm who required one or more doses of antihypertensive medication given for acute lowering of BP

The proportion of study participants in each study arm who require any IV antihypertensives to acutely lower blood pressure during their postpartum hospital stay.

Use of Opioid Analgesics, Measured in Morphine Milligram Equivalents Per Day, Stratified by Postpartum Day

Adverse events include seizure, stroke, posterior reversible encephalopathy syndrome, repeat course of IV magnesium sulfate for seizure prophylaxis.

Proportion of Study Participants in Each Study Arm With New Onset Postpartum Elevation of Liver Function Tests (AST, ALT) Above Twice the Normal Limit

Delayed postpartum hemorrhage is defined as > 1000 mL of blood loss occuring > 24 hours after delivery

Inclusion Criteria: ability to give informed consent diagnosis of a "severe" hypertensive disorder of pregnancy: preeclampsia with severe features chronic hypertension with superimposed preeclampsia with severe features HELLP syndrome: hemolysis, elevated liver function tests, low platelets eclampsia not yet delivered or less than 6 hours after delivery Exclusion Criteria: current incarceration serum creatinine > 1.0 mg/dL or suspicion of acute kidney injury AST (aspartate aminotransferase) >200 unit/L ALT (alanine aminotransferase) > 200 unit/L known allergy or sensitivity to NSAIDs or acetaminophen delivery > 6 hours prior to enrollment chronic kidney disease chronic liver disease prior liver transplant chronic infectious hepatitis gastritis gastro-esophageal reflux disease (GERD) peptic ulcer disease bleeding disorder provider feels that participation is not in the best interest of the patient