Inclusion Criteria:  Women age 18-45 with a viable single or twin intrauterine pregnancy between 22 0/7 and 33 6/7 weeks gestation based on the best obstetric estimate by ACOG criteria. Undergoing expectant management for a diagnosis of preeclampsia with severe features and already initiated on 30mg Nifedipine XL. The patient may or may not have already received acute treatment for severe blood pressures.  Exclusion Criteria:  Known allergy or adverse reaction to Nifedipine or any medical condition where Nifedipine is contraindicated, such as galactose intolerance, severe GI stricture, and GI hypomotility disorder. Participation in another trial without prior approval Currently receiving a daily dose of Nifedipine XL of 60mg or greater Continuation of alternate long-acting anti-hypertensive medication on admission Physician/provider or patient refusal Triplet or higher order pregnancy