J. Perinat. Med. 2015; 43(6): 703–706
Meg Hill*, Kathryn L. Reed and Wayne R. Cohen
Oxytocin utilization for labor induction in obese and lean women Abstract: To determine if oxytocin dosage used for labor induction differed in obese and lean women, we analyzed records of patients who underwent term labor induction and delivered vaginally. Each of a cohort of 27 patients with a body mass index (BMI) > 40 kg/m2 was matched with a patient with a BMI 37 completed weeks of gestation) induction of labor in 2011 and 2012. We stratified these into two groups: those with a
Brought to you by | University of California - San Diego Authenticated Download Date | 3/1/16 1:35 PM
704 Hill et al., Oxytocin use in obese and lean women term BMI > 40 kg/m2 (obese) and those with a BMI 2 cm) and fetal station ( ≤ 0 or > 0 station) at the initiation of labor induction. Matching was done by identifying consecutively delivered cases and choosing the first patient in the list of lean patients who met all matching criteria. We reviewed the records of these 27 matched pairs to obtain pertinent data regarding each pregnancy and delivery, including parity, use of cervical ripening drugs, and use of epidural analgesia. The total amount and dose rate of oxytocin infusion in the first stage of labor were calculated for each patient based on nursing notes in the electronic record. One author, blinded to the group to which the patient belonged, reconstructed cervical dilatation curves and analyzed them according to the method of Friedman and his co-workers [4, 9]. For purposes of this study the first stage of labor was considered to begin at the time oxytocin infusion was initiated. During the study years oxytocin was administered on our service according to a uniform protocol. Although the physician had the discretion to alter the starting dose and incremental rate changes, in general the infusion was started at 2 mU/min and increased by 2 mU/min at 15–45-min intervals until palpably firm contractions occurred every 2–3 min. The maximal allowable dose was 20 mU/min, a rate that was exceeded only after a physician had assessed the patient and certified that a higher rate was appropriate. We sought differences between the obese and lean groups using Student’s t-test for continuous variables and the χ2 or the Fischer’s exact test for categorical data.
Results In addition to the matching characteristics, there was no difference between the obese and lean groups in parity, presence of diabetes mellitus, use of epidural anesthesia, or frequency of male newborn sex (Table 1). More over, there was no difference in the use of pre-induction
Table 1 Characteristics of the sample.
Obese (n = 27)
BMI (kg/m2) 43.4 ± 3.3 Induction indication [n (%)] Elective 9 (33) Diabetes and/or hypertension 14 (52) Other medical 1(4) Postdates 1 (4) Gestational age (weeks) 38.8 ± 1.2 Birth weight (g) 3374 ± 365 Cervical dilatation
Meg Hill*, Kathryn L. Reed and Wayne R. Cohen
Oxytocin utilization for labor induction in obese and lean women Abstract: To determine if oxytocin dosage used for labor induction differed in obese and lean women, we analyzed records of patients who underwent term labor induction and delivered vaginally. Each of a cohort of 27 patients with a body mass index (BMI) > 40 kg/m2 was matched with a patient with a BMI 37 completed weeks of gestation) induction of labor in 2011 and 2012. We stratified these into two groups: those with a
Brought to you by | University of California - San Diego Authenticated Download Date | 3/1/16 1:35 PM
704 Hill et al., Oxytocin use in obese and lean women term BMI > 40 kg/m2 (obese) and those with a BMI 2 cm) and fetal station ( ≤ 0 or > 0 station) at the initiation of labor induction. Matching was done by identifying consecutively delivered cases and choosing the first patient in the list of lean patients who met all matching criteria. We reviewed the records of these 27 matched pairs to obtain pertinent data regarding each pregnancy and delivery, including parity, use of cervical ripening drugs, and use of epidural analgesia. The total amount and dose rate of oxytocin infusion in the first stage of labor were calculated for each patient based on nursing notes in the electronic record. One author, blinded to the group to which the patient belonged, reconstructed cervical dilatation curves and analyzed them according to the method of Friedman and his co-workers [4, 9]. For purposes of this study the first stage of labor was considered to begin at the time oxytocin infusion was initiated. During the study years oxytocin was administered on our service according to a uniform protocol. Although the physician had the discretion to alter the starting dose and incremental rate changes, in general the infusion was started at 2 mU/min and increased by 2 mU/min at 15–45-min intervals until palpably firm contractions occurred every 2–3 min. The maximal allowable dose was 20 mU/min, a rate that was exceeded only after a physician had assessed the patient and certified that a higher rate was appropriate. We sought differences between the obese and lean groups using Student’s t-test for continuous variables and the χ2 or the Fischer’s exact test for categorical data.
Results In addition to the matching characteristics, there was no difference between the obese and lean groups in parity, presence of diabetes mellitus, use of epidural anesthesia, or frequency of male newborn sex (Table 1). More over, there was no difference in the use of pre-induction
Table 1 Characteristics of the sample.
Obese (n = 27)
BMI (kg/m2) 43.4 ± 3.3 Induction indication [n (%)] Elective 9 (33) Diabetes and/or hypertension 14 (52) Other medical 1(4) Postdates 1 (4) Gestational age (weeks) 38.8 ± 1.2 Birth weight (g) 3374 ± 365 Cervical dilatation
