Antibiotic Prophylaxis to Prevent Obesity-Related Induction Complications in Nulliparae at Term

Antibiotic Prophylaxis to Prevent Obesity-Related Induction Complications in Nulliparae at Term (APPOINT): A Pilot Randomized Controlled Trial

Obesity increases the risk of pregnancy complications, including among others puerperal infections and cesarean delivery, and risk rises with increasing body mass index (BMI). Class III obesity is an indication for delivery by 39 weeks, and these patients have a high rate of labor induction. In nulliparous women from the general population (obese and non-obese), labor induction at 39 weeks (compared to expectant management) is associated with less morbidity and a lower cesarean rate. Antibiotic prophylaxis, standard before cesarean delivery, is associated with less post-cesarean infection if azithromycin is added to the standard cefazolin. In this placebo-controlled pilot trial, investigators will estimate the parameters necessary to calculate the sample size for a planned multicenter clinical trial of prophylactic antibiotics administered at the start of labor inductions of morbidly obese nulliparous women at term.

Investigators will enroll consenting women delivering at The Children's Hospital at OU Medical Center who meet enrollment criteria. Flyers will be distributed to providers to give to women who may be eligible for the study at prenatal visits, so that they may review the information prior to presenting for their induction of labor. Labor induction may be a scheduled procedure. However, many inductions occur in an unscheduled fashion due to medical or obstetric indications. Therefore, it is difficult to predict which women will ultimately require labor induction and at what gestational age they will require it, so it is not feasible to approach and consent all women during a clinic visit prior to labor induction. Distribution of flyers will allow patients to have information about the study prior to presenting for labor induction. Furthermore, unlike women in spontaneous labor, women being consented just prior to a labor induction are not vulnerable in the same way as one might consider a patient in labor, since they will not have the distraction and discomfort of uterine contractions that are presenting in laboring patients.

Inclusion Criteria:

• BMI ≥30
• No prior deliveries at or beyond 20 weeks gestation
• Undergoing induction of labor
• Gestational age 37 weeks or more
• Age 15-45

Exclusion Criteria:

• Fetal death prior to labor induction
• Known fetal anomaly
• Multiple gestation
• Ruptured membranes for more than 12 hours
• Chorioamnionitis or other infection requiring antibiotics at the start of the labor induction
• Previous myometrial surgery
• Allergy to either drug used in the protocol (cefazolin or azithromycin)