Preeclampsia is a disorder of widespread vascular endothelial malfunction and vasospasm that occurs after 20 weeks' gestation and can present as late as 4-6 weeks postpartum

Currently there is no effective treatment for early-onset preeclampsia except for early delivery of the fetus along with the placenta. Progesterone supplementation in the form of 17-alpha-hydroxyprogesterone caproate (17-OHPC) is currently used obstetrically to prevent recurrent preterm birth in patients with pregnancies not complicated by preeclampsia. Previous studies reported that patients with severe PE had significantly lower serum progesterone concentrations than gestational age- and race-matched non-preeclamptics. Moreover, supplementation of placental ischemic rats with 17-OHPC decreased blood pressure, inflammatory cytokines, and ET-1 within 24 hours of treatment

Inclusion Criteria:

• Gestational age between 20+0 and 33+6 weeks.
• Singleton pregnancy.
• Willing to participate in the study and sign the informed consent.

Exclusion Criteria:

• Maternal compromise requiring emergent delivery (ongoing placental abruption, DIC, pulmonary edema).
• Fetal compromise requiring emergent delivery (fetal bradycardia, recurrent late fetal heart rate decelerations).
• 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;
• Eclampsia;
• Nonreassuring fetal status during daily testing (biophysical profile <4/10 and/or recurrent variable or late decelerations);
• Intrauterine fetal death.
• Patient is unable or unwilling to give consent.
• Patients currently using progesterone for other indications.