The Impact of Cervical Effacement at Time of Amniotomy in Patients Undergoing Induction of Labor

Abstract

Objective There is evidence to suggest that early amniotomy during induction of labor is advantageous. However, following cervical ripening balloon removal, the cervix remains less effaced and the utility of amniotomy in this setting is less clear. We investigated whether cervical effacement at the time of amniotomy impacts outcomes among nulliparas undergoing induction of labor.

Study Design This was a secondary analysis of a prospective cohort of singleton, term, nulliparous patients at a tertiary care center undergoing induction of labor and amniotomy. The primary outcome was completion of the first stage of labor. Secondary outcomes were vaginal delivery and postpartum hemorrhage. Outcomes were compared between patients with cervical effacement ≤50% (low effacement) and >50% (high effacement) at time of amniotomy. Multivariable logistic regression was used calculate risk ratios (RR) to adjust for confounders including cervical dilation. Stratified analysis was performed in patients with cervical ripening balloon use. A post hoc sensitivity analysis was performed to further control for cervical dilation.

Results Of 1,256 patients, 365 (29%) underwent amniotomy at low effacement. Amniotomy at low effacement was associated with reduced likelihood of completing the first stage (aRR: 0.87 [95% confidence interval, CI: 0.78–0.95]) and vaginal delivery (aRR: 0.87 [95% CI: 0.77–0.96]). Although amniotomy at low effacement was associated with lower likelihood of completing the first stage in all-comers, those who had amniotomy performed at low effacement following cervical ripening balloon expulsion were at the highest risk (aRR: 0.84 [95% CI: 0.69–0.98], p for interaction = 0.04) In the post hoc sensitivity analysis, including patients who underwent amniotomy at 3- or 4-cm dilation, low cervical effacement remained associated with a lower likelihood of completing the first stage of labor.

Conclusion Low cervical effacement at time of amniotomy, particularly following cervical ripening balloon expulsion, is associated with a lower likelihood of successful induction.

Key Points

• Low cervical effacement at amniotomy was associated with lower rates of complete dilation.

• Effacement at amniotomy is especially important for patients who had a cervical ripening balloon.

• Providers should consider cervical effacement when timing amniotomy for nulliparous term patients.

Keywords

induction - amniotomy - nulliparous - cervical effacement

Note

This study was previously presented as poster no. 958 at the 42nd Annual Pregnancy Meeting, Society for Maternal-Fetal Medicine (February 4, 2022).

Publikationsverlauf

Eingereicht: 28. Februar 2023

Angenommen: 18. Mai 2023

Accepted Manuscript online:
19. Mai 2023

Artikel online veröffentlicht:
19. Juni 2023

• References

• 1 Grobman WA, Rice MM, Reddy UM. et al; Eunice Kennedy Shriver National Institute of Child Health and Human Development Maternal–Fetal Medicine Units Network. Labor induction versus expectant management in low-risk nulliparous women. N Engl J Med 2018; 379 (06) 513-523
• 2 Cooney LG, Bastek JA. The association between early artificial amniotomy and chorioamnionitis in nulliparous induction of labor. Int Sch Res Notices 2014; 2014: 628452
• 3 Mercer BM, McNanley T, O'Brien JM, Randal L, Sibai BM. Early versus late amniotomy for labor induction: a randomized trial. Am J Obstet Gynecol 1995; 173 (04) 1321-1325
• 4 De Vivo V, Carbone L, Saccone G. et al. Early amniotomy after cervical ripening for induction of labor: a systematic review and meta-analysis of randomized controlled trials. Am J Obstet Gynecol 2020; 222 (04) 320-329
• 5 Battarbee AN. et al. Association of early amniotomy after cervical ripening balloon catheter ripening and duration of nulliparous labor induction. Obstet Gynecol 2016; 128 (03) 592-597
• 6 Bala A, Bagga R, Kalra J, Dutta S. Early versus delayed amniotomy during labor induction with oxytocin in women with Bishop's score of ≥6: a randomized trial. J Matern Fetal Neonatal Med 2018; 31 (22) 2994-3001
• 7 Macones GA, Cahill A, Stamilio DM, Odibo AO. The efficacy of early amniotomy in nulliparous labor induction: a randomized controlled trial. Am J Obstet Gynecol 2012; 207 (05) 403.e1-403.e5
• 8 Pasko DN, Miller KM, Jauk VC, Subramaniam A. Pregnancy outcomes after early amniotomy among class III obese gravidas undergoing induction of labor. Am J Perinatol 2019; 36 (05) 449-454
• 9 Varvoutis MS, Sayres LC, Dotters-Katz SK. Is early amniotomy associated with higher likelihood of vaginal birth after cesarean?. AJP Rep 2020; 10 (01) e37-e41
• 10 Rath W, Kehl S. The renaissance of transcervical balloon catheters for cervical ripening and labour induction. Geburtshilfe Frauenheilkd 2015; 75 (11) 1130-1139
• 11 Cahill AG, Tuuli MG, Stout MJ, López JD, Macones GA. A prospective cohort study of fetal heart rate monitoring: deceleration area is predictive of fetal acidemia. Am J Obstet Gynecol 2018; 218 (05) 523.e1-523.e12
• 12 Zhang J, Yu KF. What's the relative risk? A method of correcting the odds ratio in cohort studies of common outcomes. JAMA 1998; 280 (19) 1690-1691
• 13 Gomez Slagle HB. et al. Early vs expectant artificial rupture of membranes following cervical ripening balloon catheter ripening: a randomized controlled trial. Am J Obstet Gynecol 2021
• 14 Levy R. et al. A randomised comparison of early versus late amniotomy following cervical ripening with a cervical ripening balloon catheter. BJOG 2002; 109 (02) 168-172
• 15 Polónia Valente R, Santos P, Ferraz T, Montenegro N, Rodrigues T. Effect of obesity on labor duration among nulliparous women with epidural analgesia. J Matern Fetal Neonatal Med 2020; 33 (13) 2195-2201
• 16 Hilliard AM, Chauhan SP, Zhao Y, Rankins NC. Effect of obesity on length of labor in nulliparous women. Am J Perinatol 2012; 29 (02) 127-132
• 17 Battarbee AN, Glover AV, Stamilio DM. Association between early amniotomy in labour induction and severe maternal and neonatal morbidity. Aust N Z J Obstet Gynaecol 2020; 60 (01) 108-114
• 18 Raghuraman N, Stout MJ, Young OM. et al. Utility of the simplified Bishop score in spontaneous labor. Am J Perinatol 2016; 33 (12) 1176-1181
• 19 Tan PC, Vallikkannu N, Suguna S, Quek KF, Hassan J. Transvaginal sonographic measurement of cervical length vs. Bishop score in labor induction at term: tolerability and prediction of cesarean delivery. Ultrasound Obstet Gynecol 2007; 29 (05) 568-573
• 20 Strobel E, Sladkevicius P, Rovas L, De Smet F, Karlsson ED, Valentin L. Bishop score and ultrasound assessment of the cervix for prediction of time to onset of labor and time to delivery in prolonged pregnancy. Ultrasound Obstet Gynecol 2006; 28 (03) 298-305
• 21 Kim SW, Nasioudis D, Levine LD. Role of early amniotomy with induced labor: a systematic review of literature and meta-analysis. Am J Obstet Gynecol MFM 2019; 1 (04) 100052
• 22 Wei S, Wo BL, Qi HP. et al. Early amniotomy and early oxytocin for prevention of, or therapy for, delay in first stage spontaneous labour compared with routine care. Cochrane Database Syst Rev 2013; (08) CD006794
• 23 Bréart G, Mlika-Cabane N, Kaminski M. et al. Evaluation of different policies for the management of labour. Early Hum Dev 1992; 29 (1-3): 309-312
• 24 Cammu H, Van Eeckhout E. A randomised controlled trial of early versus delayed use of amniotomy and oxytocin infusion in nulliparous labour. Br J Obstet Gynaecol 1996; 103 (04) 313-318
• 25 Rogers R, Gilson GJ, Miller AC, Izquierdo LE, Curet LB, Qualls CR. Active management of labor: does it make a difference?. Am J Obstet Gynecol 1997; 177 (03) 599-605
• 26 Sadler LC, Davison T, McCowan LM. A randomised controlled trial and meta-analysis of active management of labour. BJOG 2000; 107 (07) 909-915
• 27 Tabowei TO, Oboro VO. Active management of labour in a district hospital setting. J Obstet Gynaecol 2003; 23 (01) 9-12
• 28 Zhang J, Landy HJ, Ware Branch D. et al; Consortium on Safe Labor. Contemporary patterns of spontaneous labor with normal neonatal outcomes. Obstet Gynecol 2010; 116 (06) 1281-1287