The investigators will collect omental tissue (research surgical excision) and placental tissue (standard of care clinical delivery) from both preeclamptic and non-preeclamptic women during their c-section and use these samples to study the blood vessels, specifically the expression/activation of the AT2R.

Trial Design: The study is a comparison of two cohorts, those with and without preeclampsia during pregnancy. The team plans to investigate role of FABP4, PFAS and AT2 in modulation of vascular function/dysfunction using vessels isolated from the omental biopsies. The investigators will examine evidence of fetal vascular dysfunction mediated by decreased expression of AT2 in preeclampsia using vessels isolated from the placentas.

Study Population: The study will include pregnant women. The pregnant women will participate in the omental tissue collection, placenta collection, and the medical record review.

The study is expects a maximum enrollment of 166 pregnant women. This is because 52 omental biopsies and 104 placentas are required to meet proposed statistical considerations. Participants have the option of providing just one or both of the specimens. There is a possibility as few as 52 participants could be enrolled and a maximum of 166 participants could be enrolled to meet this requirement. There is an additional 10 participants enrollment built into the enrollment number to allow for replacement of subjects based on lack of clinical data in some participants, failure of tissue viability and hence experiments, and thus a maximum of 166 (156+10) participants could be enrolled.

This required enrollment is divided into two cohorts based on the diagnosis of preeclampsia: specimens in which the woman was diagnosed with preeclampsia during her pregnancy, and 26 of each type of specimen in which the woman was not diagnosed with preeclampsia during her pregnancy. Additionally, each cohort will be divided into two groups based on gender of the fetus.

Inclusion Criteria:

• Female
• Ages 18 to 40 years old
• Singleton gestation between 28 weeks, 0 days and 41 weeks, 0 days gestational age at the time of consent
• Undergoing caesarean section, either planned or otherwise with or without trial of labor

Exclusion Criteria:

• Treatment of severe hypertension by antihypertensive or use of magnesium sulfate after the patient is hospitalized for the diagnosis of preeclampsia.
• Any major fetal structural anomalies or aneuploidies
• Undergoing cesarean section for placental abruption or bleeding complications.
• Singleton gestation not within 36 weeks, 0 days and 41 weeks, 0 days gestational age at the time of enrollment (delivery)

Pregnant women with or without Preeclampsia who will be undergoing a C-section