Surgical site infections are common and a cause of major morbidity. They are also more common in obese women. Cesarean sections are the most common surgery performed in the United States, therefore pregnant women are being faced with this problem frequently. There is evidence to show that prophylactically administered antibiotics, cefazolin specifically, to obese women prior to cesarean section do not reach adequate concentrations in adipose tissue to prevent infection. The purpose of this study is to evaluate if an increased dose of cefazolin will attain adequate tissue concentration in obese women. Our hypothesis is that three grams of cefazolin given no more than 60 minutes prior to the start of a cesarean section in an obese (Body mass index (BMI) greater than or equal to 30) woman will attain adequate adipose tissue concentration compared to two grams of cefazolin.

Subjects will be selected if they are greater than 37 weeks gestation wiht a singleton pregnancy and require a cesarean section for any obstetrical indication. Women will be excluded if they have a suspected infection, have a multiple gestation, or have preexisting diabetes or hypertension with end organ damage. The subjects will be screened both by through the OR schedule as well as through the clinics. They will then be consented and enrolled by the primary investigator. Once enrolled the subjects will be randomized to receive either two grams or three grams of cefazolin as prophylactic antibiotics to be given no more than 60 minutes prior to the start of the surgery.

Two adipose tissue samples will be obtained at the time of surgery. The first at the start after skin incision and the second at the end prior to closure of the skin. There will also be a separate IV placed at the start of the procedure from which three blood draws can be collected. These three samples will be obtained at the start of the surgery but after antibiotic administration, at the time of the first adipose collection, and at the time of the second adipose collection. The samples will then be stored at -80 degrees and shipped to David P. Nicolau's lab in Hartford, CT for the tissue and serum analysis.

While the subjects are in the hospital recovering from their surgery, a chart review will be performed to determine if there are any infections occuring post-operatively. A telephone survey will be conducted six to eight weeks postpartum again assessing for any infectious complications after the cesarean section.

Inclusion Criteria:

• Obese - body mass index (BMI) calculated as weight (kg)/ [height (m2)]greater than or equal to 30 as determined at their first prenatal visit
• Gestational age of 37 0/7 weeks and greater
• Singleton Pregnancy
• Non-emergent cesarean section

Exclusion Criteria:

• Known cephalosporin allergy
• Severe allergy to penicillin making cephalosporin use a contraindication
• Exposure to antibiotics in the preceding 7 days
• Need for emergent cesarean section
• Multiple gestations
• Suspected chorioamnionitis
• Pre-gestational diabetes
• Chronic hypertension with evidence of end organ damage