Characterizing uterine responsiveness to oxytocin augmentation across four labor patterns in maternal obesity.

BACKGROUND: Optimizing care during labor protraction is a key strategy for reducing cesareans, especially among people with obesity. The pathophysiology of labor dystocia remains poorly understood, limiting precise interventions targeting the cause of protraction. METHODS: In this secondary analysis of nulliparas (n = 92) with obesity (BMI ≥ 30 kg/m2 ) and spontaneous labor onset, we classified labor into four phenotypes based on duration of protraction and birth route: (1) no protraction, (2) short protraction and vaginal birth, (3) extended protraction meeting criteria for labor arrest, but with eventual progression and vaginal birth, and (4) extended protraction meeting criteria for labor arrest and cesarean birth. Across these phenotypes, we compared MVU, oxytocin dose, and novel measures of uterine responsiveness to oxytocin augmentation (MVU to oxytocin dose ratios). RESULTS: In our sample, phenotype group 1 comprised 14.1% (n = 13); group 2 comprised 30.4% (n = 28); group 3 comprised 34.8% (n = 32); and group 4 comprised 20.7% (n = 19). Uterine responsiveness to oxytocin, but not MVU, decreased with each labor phenotype. Participants with cesarean birth had the lowest uterine responsiveness to oxytocin. CONCLUSION: Labor and birth outcomes were associated with measures of uterine responsiveness to oxytocin rather than MVU alone, and thus these may be more clinically appropriate measures for guiding clinical decision-making. Current criteria for labor arrest are likely too stringent for nulliparas with obesity, many of whom appear to progress to safe vaginal birth after longer labor durations. Differences in uterine responsiveness to oxytocin augmentation across the groups suggests underlying physiologic differences in the labor phenotypes, which should drive future research targeting pathophysiology.

The Relationship Between Uterine Activity, Oxytocin Dosing, Labor Progress, and Mode of Birth in Nulliparas with Obesity: Minimal Usefulness of Montevideo Unit Measurement.

BACKGROUND: Maternal obesity and cesarean birth disproportionately affect Black parturients; thus, prevention of cesarean birth is a key modifiable factor to improve pregnancy outcomes and reduce disparities. The primary driver of unplanned cesarean birth among people with higher body mass index is prolonged labor duration. However, strategies to optimize outcomes in these situations have not been established. We aimed to evaluate the influence of oxytocin augmentation on uterine activity and labor progression in nulliparas with obesity. METHODS: This secondary analysis involved nulliparas with obesity (BMI ≥30 kg/m2) who had spontaneous labor onset followed by oxytocin augmentation and an intrauterine pressure catheter. Using Linear Mixed Models, we evaluated relationships between uterine activity measured in Montevideo units (MVU), oxytocin dose, and rate of cervical dilation normalized by labor duration. RESULTS: In this diverse sample (35.6% Caucasian, 16.11% African American, 40.2% Hispanic) of nulliparas with obesity (n = 87; BMI 35.54 ± 4.38 kg/m2), 31% ended labor with cesarean birth. Among those with vaginal birth, only 13% had MVU ≥200 prior to the final 2 hours of labor. MVUs were only minimally responsive to oxytocin dose and were not associated with labor progression nor birth route. CONCLUSION: MVU measurements may not be useful to diagnose labor arrest in nulliparas with obesity. Optimizing care for birthing people with obesity is essential for improving perinatal outcomes and for reducing racial health disparities.

Prenatal and Postpartum Experience, Knowledge and Engagement with Kegels: A Longitudinal, Prospective, Multisite Study.

Introduction: Urinary incontinence (UI) increases during pregnancy and continues into the postpartum period. Continued UI impacts women's comfort and affects aspects of their everyday lives. Kegel exercises have been found to decrease the incidence and severity of UI. The purpose of this study was to describe severity of UI, how women gained knowledge about Kegels, influences impacting Kegel exercises during pregnancy and postpartum, and characterize women's performance of Kegels. Methods: A longitudinal, prospective, multistate study was undertaken at four sites across the United States. Postpartum women completed the Pelvic Floor Control Questionnaire that incorporated the Sandvik Severity Index. At 3 and 6 months postpartum the women's UI, performance of Kegels, and affect on life was reviewed through seven questions. Institutional Review Board (IRB) approval was obtained. Results: Participants were 368 predominately multiparous, white women. Approximately 20% of women reported prepregnancy UI. Multiparous women reported similar incidence rate of UI regardless of birth history. Among one-fifth of the participants, persistent UI was reported as 45.2% at 3 months and 44.1% at 6 months postpartum. Only 25% of these women sought care. Women learned about Kegel exercises from written information or their provider. Women performed an average 16 Kegels twice daily. Kegel performance increased at 3 months postbirth but dropped by 6 months. UI was associated with age >35 and parity. Discussion: Prevalence of UI before and during pregnancy and postpartum is high, yet consistent Kegel performance postpartum is low. Screening for UI is necessary and high-quality referrals for treatment are needed. Consistent education is needed for all women. Education and support should be individualized. Future research is needed to identify techniques that motivate women to routinely perform Kegel exercises.

An Integrated Review of Uterine Activity Monitoring for Evaluating Labor Dystocia.

INTRODUCTION: Labor dystocia is the most common cause of cesarean birth in the United States, yet how dystocia develops during labor remains elusive. Uterine activity monitoring has significant potential for advancing our understanding of labor dystocia. While evaluating contraction frequency and amplitude is a common component of labor dystocia management, the literature describing the relationship between measures of uterine activity and labor dystocia is heterogeneous and has not been synthesized to identify the best methods for use in clinical investigation. METHODS: We conducted a literature search for original research exploring the relationship between uterine activity and labor dystocia published between 2000 and 2019. Included articles were critically reviewed and synthesized. RESULTS: Across 11 identified studies, investigators employed 3 different techniques for monitoring uterine activity and 9 different measures were employed. Uterine activity measures, including Montevideo units, uterine electromyography power density spectrum and sample entropy, and the fall-to-rise ratio of contraction shape, detected patterns associated with labor dystocia or cesarean birth. DISCUSSION: The use of multiple regression with clinical covariates and a uterine activity measure increased the accuracy of predicting cesarean delivery. Uterine electromyography may be especially useful to evaluate labor dystocia phenotypes to differentiate uterine muscle fatigue from understimulation and lead to algorithms for increased precision in the diagnosis of labor dystocia and innovative approaches to treatment.