Date of Award

January 2021

Document Type


Degree Name

Medical Doctor (MD)



First Advisor

Jessica L. Illuzzi



Gwendolyn Towers, Michelle Telfer, Jessica L. Illuzzi. Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale University School of Medicine, New Haven, CT

Nitrous oxide labor analgesia is growing in popularity in the United States, with little known regarding the factors driving this trend or about women’s experiences with the method. This study, which includes both a quantitative and a qualitative component, contributes to our understanding of the use of nitrous oxide labor analgesia in the US by exploring the following: (1) who uses the method and how these women differ from women who labor with no pharmacologic analgesia or with only neuraxial analgesia; (2) why women choose to use nitrous oxide; and (3) what their experiences are like. Using medical record and survey data, we compared demographic and clinical characteristics of women who used nitrous oxide, with or without epidural, to women who used no pharmacologic pain management and women who used only epidural. A subset of women using nitrous oxide was interviewed, and emergent themes were identified. In our sample of 107 parturients, 34% used nitrous oxide, with or without epidural, 36% received epidural only, and 30% received no pharmacologic analgesia. Women using nitrous oxide had lower parity (median=1, interquartile range [IQR]=1) and longer labor duration (median=10 hours, IQR=19.1) compared to women receiving no pharmacologic analgesia (median=2, IQR=1; median=2.7 hours, IQR=3.5, respectively). Their proportions of women undergoing labor augmentation (19.4%) and cesarean birth (13.9%) were lower than those receiving epidural alone (35.9%; 28.2%, respectively) and higher than those using no pharmacologic pain management (6.3%; 6.3%, respectively). Most women using nitrous oxide expressed being motivated by interest in low-intervention birth. Half of women using nitrous oxide progressed to neuraxial analgesia, with inadequate pain control and exhaustion the most commonly cited reasons for the transition. Though many women using nitrous oxide reported inadequate pain relief, most reported that it nonetheless improved their experiences and enhanced their feelings of control over their births. In our study, women interested in low-intervention birth perceived nitrous oxide as an attractive complement to their labors. Despite providing incomplete analgesia, nitrous oxide may enhance women’s feelings of control and facilitate empowering birth experiences.


This thesis is restricted to Yale network users only. It will be made publicly available on 10/12/2023