A previous study performed at University of California, Irvine (UCI) and Long Beach Memorial Medical Center/Miller Children's Hospital (LBMMC) showed that the standard dose of antibiotics (2 grams of cefazolin) did not provide adequate coverage for all organisms in the obese and extremely obese populations. The purpose of this research study is to evaluate whether in increased dose of antibiotics given before cesarean delivery (3 grams of cefazolin) will reach adequate levels in adipose (fat cells underneath the skin) and serum (blood) samples. In addition, researchers hope to evaluate if/how the mother's weight has an effect on the levels of antibiotics in the tissues (a group of similar cells).