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CC BY-NC-ND 4.0 · AJP Rep 2019; 09(02): e177-e184
DOI: 10.1055/s-0039-1692196
Original Article
Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Oxytocin and Oxytocinase in the Obese and Nonobese Parturients during Induction and Augmentation of Labor

Authors

  • Annemaria De Tina

    1   Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
    2   Department of Anesthesiology, McMaster University, Hamilton, Ontario, Canada

  • Jeremy Juang

    1   Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
    3   Department of Anesthesiology, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts

  • Thomas F. McElrath

    4   Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts

  • Jack D. Baty

    5   Division of Biostatistics, Washington University School of Medicine, St. Louis, Missouri

  • Arvind Palanisamy 

    6   Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri
Further Information

Publication History

27 January 2019

12 April 2019

Publication Date:
29 May 2019 (online)

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Abstract

Objective To investigate differences in oxytocin (OXT) biodistribution between nonobese and obese parturients during labor.

Study Design Patients with body mass index (BMI) of either ≥ 18 ≤ 24.9 kg/m2 (“nonobese”) or ≥ 30 kg/m2 (“obese”) undergoing elective induction of labor were included (N = 25 each). Blood samples were collected at baseline (T0), and 20 minutes after maximal OXT augmentation or adequate uterine contractions (T1) for OXT and oxytocinase assays. A mixed-model repeated-measures analysis of variance was used to test for group versus time interaction and analysis of covariance to detect a difference in OXT level at T1. Data presented as mean ± standard deviation or median (interquartile range), with p < 0.05 considered significant.

Results The mean BMIs (kg/m2) were 22.1 ± 1.6 and 35.9 ± 5.1 in the nonobese and obese groups, respectively. No differences were observed in either the duration of OXT infusion, total dose of OXT, or plasma OXT (pg/mL) either at T0 or T1. However, plasma oxytocinase (ng/mL) was significantly lower at T0 (1.41 [0.67, 3.51] vs. 0.40 [0.29, 1.12]; p = 0.03) in the obese group.

Conclusion We provide preliminary evidence that the disposition of OXT may not be different between obese and nonobese women during labor.

Keywords

obesity - pregnancy - oxytocin - induction of labor - augmentation of labor - oxytocinase

Authors' Contribution

A.D.T.: This author helped design the study, conducted the study, reviewed analysis, wrote, and approved the final article.


J.J.: This author helped conduct the study, reviewed analysis, wrote, and approved the final article.


T.F.M.: This author helped design the study, reviewed analysis, and approved the final article.


J.D.B.: This author performed statistical analysis and approved the final article.


A.P.: This author conceived the study, designed the study, conducted the study, reviewed analysis, wrote, and approved the final article.


Competing Interest

The authors declare no competing interest.