This study's aim is to determine whether oral extended release nifedipine is superior to oral labetolol for the management of postpartum severe hypertension, specifically time to achieve goal blood pressure, and shortening hospital stay. Our hypothesis is that oral extended release nifedipine is superior to oral labetolol for achieving goal blood pressure in the postpartum period.

Hypertension complicating pregnancy is common and, when uncontrolled, can have devastating consequences. While the true incidence of postpartum hypertension is unknown, blood pressure (BP) is known to initially decrease 48 hours following delivery then peak on postpartum days 3-6, likely 45 from the mobilization of interstitial fluids following parturition.

The American College of Obstetricians and Gynecologists (ACOG) recommends medical treatment of persistent postpartum hypertension, defined as systolic BP (SBP) ≥150 mmHg or diastolic BP (DBP) ≥100 mmHg, on two or more occasions 4-6 hours apart. Prior studies compared intravenous medications to intramuscular and immediate-release oral 50 medications in the treatment of postpartum hypertension. However, oral labetalol and oral extended release nifedipine are the most commonly used medications for post- partum hypertension, and their efficacy has not been directly compared.

Our aim was to determine whether oral labetalol is associated with a shorter time to BP control compared to oral extended release nifedipine for management of persistent 55 postpartum hypertension. Our primary outcome was time to sustained BP control defined as the absence of severe hypertension (SBP ≥160 mmHg or DBP ≥105 mmHg) for at least 12 hours. Secondary outcomes included postpartum length of stay, need for increased dosing, need for additional oral antihypertensive agents, and patient-reported side effects.

Inclusion Criteria:

• Age ≥ 18 years with the abililty to give informed consent
• Intrauterine pregnancy ≥ 32 weeks
• Postpartum
• Persistent postpartum blood pressures ≥ 160/105 on two or more occasions
• Primary obstetrician amenable to starting either study medication in the postpartum period

Exclusion Criteria:

• Use of other oral antihypertensives concomitantly
• Known AV heart block
• HR <60 or >120
• Absolute contraindication to nifedipine or labetolol such as allergy
• Significant renal disease (Cr >1.5 mg/dL)
• Heart failure
• Moderate persistent or severe asthma
• Preexisting diagnosis of chronic hypertension with medical treatment before delivery
• Chronic hypertension