Peri-operative Cefazolin Prophylaxis at Time of Cesarean Delivery in the Obese Gravida

Obesity has become an increasingly prevalent public health problem in the United States, reaching epidemic proportions. According to 2009 CDC epidemiologic data on obesity in the United States, 35.7% of the United States population is considered overweight or obese. Currently, on the review of the literature, over 20% of pregnancies in this country are complicated by maternal obesity. Obesity has been well demonstrated to be correlated with numerous adverse pregnancy outcomes such hypertensive disorders of pregnancy, gestational diabetes, and increased rates of operative delivery. Moreover, obesity, irrespective of pregnancy, has been demonstrated to be an independent risk factor for the development of postoperative surgical site infections. Development of such infections can have both consequential long-term medical sequelae for patients and economic impacts on the health care system at large. Cefazolin, a first generation hydrophilic cephalosporin whose clearance is exclusively mediated via the kidneys unchanged, is used as pre-operative antibiotic prophylaxis for cesarean deliveries. The current accepted standard of care is to administer 2 grams of cefazolin within 60 minutes of skin incision. Studies of drug concentrations of cephalosporins for pre-operative antibiotic prophylaxis in obese bariatric patients have shown that therapeutic concentrations may not be achieved in both tissue and plasma. Limited data exist in pregnancy. Therefore, it is the goal of this study to investigate whether obese patients presenting for cesarean delivery require an increased dosing amount of pre-operative antibiotic prophylaxis. This study will randomized women with a pre-pregnancy body mass index of 30 kg/m2 or more who are presenting for their scheduled cesarean delivery to receive either 2 grams or 3 grams of cefazolin for pre-operative antibiotic prophylaxis. By drawing blood at specific time points in the peri-operative period and extracting adipose tissue samples during cesarean delivery, this study will investigate the pharmacokinetics of cefazolin in both the plasma and tissues of the obese gravida.