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.