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 <28 kg/m2 for gestational age, for birth weight, and for cervical dilatation and fetal station at admission. The oxytocin dose administered during first stage labor was calculated for each patient. In addition to the matched characteristics, there was no difference between groups in parity, frequency of diabetes, epidural anesthesia use, or pharmacologic cervical ripening. Oxytocin utilization was significantly greater in obese women than in lean women. The maximum administration rate was 17.7±4.7 and 13.1±5.0 mU/min, respectively (P=0.001). Oxytocin administered per minute during the first stage of labor was greater in the obese group (11.6±4.8 vs. 8.6±4.1 mU/min; P=0.020). Neither active phase duration nor the maximum rate of dilatation differed significantly between the groups. That obese parturients required more oxytocin than lean women during the first stage of successful labor induction could not be explained by group differences in parity, birth weight, dysfunctional labor, pre-induction dilatation and station, or epidural use.

Influence of body mass index on induction of labor: A historical cohort study

“…Oxytocin augmentation was not different in the present study. In contrast to this finding, previous investigations found higher doses of oxytocin necessary during induction of labor and labor in obese women …”

“…Similar results were reported by Lassiter et al , but they did not stratify for parity . Further studies investigated the length of labor and did not find any difference . Multiple analysis demonstrated that BMI as well as parity, gestational age, and Bishop score were associated with induction‐to‐delivery interval.…”

“…All of these authors came to the conclusion that labor progression is slower when BMI increases. Others did not find any difference in length of labor, but these studies are limited by the small numbers of included women ( n = 27 and n = 413).…”

“…On the one hand, induction of labor in obese women was reported to be more likely to be prolonged, leading to the requirements for higher doses of oxytocin and increased risks of operative deliveries and morbidity . On the other hand, some investigators have claimed that there is no difference in length of labor in obese women with induction of labor . The aim of the present study was therefore to determine the influence of BMI on induction of labor at term.…”

Oxytocin and obesity: 2015-2017 literature review on oxytocin use in obese women

“…This effect was seen in Hill M et al study as well. In a retrospective review, amongst a cohort of 54-term women undergoing induction of labor with subsequent vaginal deliveries, obese women (BMI > 40 kg/ m 2 ) required more oxytocin than lean women during the first stage of labor when matched for parity, diabetes, epidural use, birth weight, pre-induction dilatation, and station [9]. In attempts of explaining this phenomenon, HajagosToth et al reviewed the influences of increased body weight on multiple endocrine and paracrine systems.…”