The purpose of this study is to learn if giving 17-hydroxyprogesterone caproate (17 OHPC) to mothers with preeclampsia diagnosed before 34 weeks gestation improves mother and baby outcomes.

The OBGYN house and attending staff on duty caring for the patient will determine appropriateness for study inclusion. The treating physician will then immediately contact the MFM fellow on call and Research Division personnel to facilitate the initiation of study procedures, including the consent process and baseline blood tests. Once enrolled with informed consent, the participant will receive 17 OHPC, 250mg IM to be given at admission and every 7 days thereafter. Blood sampling of approximately 1-2 teaspoons each will be collected at baseline immediately prior to administration of 17 OHPC, then 24 hours (+-2hrs). After the first 24 hours, blood samples will be collected every 72 hrs until delivery and again 24hrs (+- 2hrs) after delivery. Placentas will be collected at delivery and the investigators will also collect information of the mother and newborn while in the hospital and until discharge including de-identified routine ultrasound.

Inclusion Criteria:

• UMMC antepartum patients with preterm PE between 23 0/7ths and 34 0/7ths weeks gestation when initially evaluated
• Willing and able to understand study procedures and to provide informed consent

Exclusion Criteria:

• >33 weeks gestational age or <23 weeks gestation
• Maternal compromise requiring emergent delivery (ongoing placental abruption, DIC, pulmonary edema).
• Fetal compromise requiring emergent delivery (fetal bradycardia, recurrent late fetal heart rate decelerations, minimal to absent fetal heart rate variability).
• Parameters according to current practice guidelines that exclude a patient from expectant management include the following:
• Preterm premature rupture of membranes (PPROM) > 34 weeks gestation;
• Platelet count < 100,000/microliter (thrombocytopenia) with evidence of HELLP syndrome;
• Persistently abnormal hepatic enzyme concentrations (twice or more upper normal values);
• Severe fetal growth restriction (ultrasound-estimated fetal weight less than fifth percentile);
• Severe Oligohydramnios (AFI < 5cm)
• Reversal of end diastolic flow(REDF) in umbilical artery Doppler testing;
• Recurrent (> 2 readings > 30 minutes apart) severe hypertension despite antihypertensive therapy;
• Eclampsia;
• Pulmonary edema;
• Abruption placentae;
• Nonreassuring fetal status during daily testing (biophysical profile <4/10 and/or recurrent variable or late decelerations);
• IUFD

Female only