The purpose of this study is to determine whether placental and umbilical cord blood miRNA expression is altered in women with obesity with macrosomic neonates to when compared to miRNA expression from control patients.

MicroRNA's are a class of non-coding RNA's that function as translational repressors and are thought to modulate tissue development, proliferation, differentiation and function. Differential expression of certain placental miRNA's has been associated with preeclampsia.

The fetal origins of adult disease hypothesis suggests that risk factors from intrauterine environmental exposures affect the fetus' development during sensitive periods, and increases the risk of specific diseases in adult life. Our aim is to understand factors that predispose fetuses to fetal overgrowth in utero, especially in women with obesity. The objective of the study is to identify miRNA which are differentially expressed in the placenta and cord blood of pregnancies that are affected by fetal macrosomia to determine factors that may predispose fetuses to fetal overgrowth.

Inclusion Criteria:

• singleton pregnancy
• prenatal care & delivery at the Hospital of the University of Pennsylvania system
• Normal glucose tolerance test results (less than 120 mg/dl)

Exclusion Criteria:

• Multiple gestation
• under 18 years old, or over 45 years old
• chronic hypertension
• preeclampsia
• chronic steroid use
• diabetes
• major fetal anomaly
• connective tissue disorder requiring medication
• active HIV
• Hepatitis C

All patients delivering in the labor and delivery unit at the Hospital of the University of Pennsylvania.