Risk factors for Caesarean delivery after induction of labour among nulliparous women at term

Selina Tsz-Ching LEE; Winnie Wai-Yan YEUNG; Kwok-Yin LEUNG

doi:10.12809/hkjgom.20.1.06

Authors

Selina Tsz-Ching LEE
Winnie Wai-Yan YEUNG
Kwok-Yin LEUNG

DOI:

https://doi.org/10.12809/hkjgom.20.1.06

Keywords:

Cesarean section, Labor, induced, Nomograms

Abstract

Objectives: To determine risk factors for Caesarean section after induction of labour (IOL) at term among nulliparous women, and to develop and validate a predictive model.
Methods: We retrospectively reviewed records of all nulliparous women with term, singleton, cephalic pregnancies and induction of labour from 1 January to 31 December 2017 in Queen Elizabeth Hospital. The cervix was examined on admission using the Modified Bishop Score for cervical dilatation, effacement, position, consistency, fetal station. Women with unfavourable cervix received cervical priming. Those with favourable cervix proceeded to induction of labour by combining artificial rupture of membrane and oxytocin infusion. Risk factors for Caesarean delivery were identified using univariable analysis and multivariable logistic regression. A nomogram was constructed using the independent risk factors. A receiver-operating characteristics curve and the area under the curve were generated to assess the discriminative power of the predictive model. An external validation was performed.
Results: A total of 1557 women who were nulliparous and had term, singleton, cephalic pregnancies and induction of labour were included for analysis. 1426 (91.6%) of them were of Chinese ethnicity. Of the 1557 women, 473 (30.4%) underwent Caesarean delivery and the remaining 1084 women delivered vaginally. In the multivariable logistic regression, independent risk factors for Caesarean delivery were maternal age (odds ratio [OR]=1.04, p=0.005), baseline height (OR=0.954, p=0.001), final body mass index (OR=1.11, p=0.001), and need for cervical priming (OR=1.32, p=0.033). The discriminative power of the predictive model was assessed by the area under the curve, which was 0.661 for the study cohort and 0.613 for the external validation set of 142 women.
Conclusion: Among Hong Kong nulliparous women with induction of labour at term, independent risk factors for Caesarean delivery were older maternal age, lower baseline height, higher final body mass index, and more need for cervical priming. The predictive model based on these risk factors can calculate the probability of Caesarean section for counselling these women.

References

ACOG Committee on Practice Bulletins -- Obstetrics. ACOG Practice Bulletin No. 107: Induction of labor. Obstet Gynecol 2009;114:386-97.

Osterman MJK, Martin JA. Recent declines in induction of labor by gestational age. Centers for Disease Control and Prevention. Available at: https://www.cdc.gov/nchs/data/databriefs/db155.pdf. Accessed 29 July 2019.

Seyb ST, Berka RJ, Socol ML, Dooley SL. Risk of cesarean delivery with elective induction of labor at term in nulliparous women. Obstet Gynecol 1999;94:600-7.

Rouse DJ, Weiner SJ, Bloom SL, et al. Failed labour induction: toward an objective diagnosis. Obstet Gynecol 2011;117:267-72.

Field A, Haloob R. Complications of caesarean section. Obstet Gynaecol 2016;18:265-72.

Miller DA, Chollet JA, Goodwin TM. Clinical risk factors for placenta previa-placenta accreta. Am J Obstet Gynecol 1997;177:210-4.

Kwee A, Bots ML, Visser GH, Bruinse HW. Obstetric management and outcome of pregnancy in women with a history of caesarean section in the Netherlands. Eur J Obstet Gynecol Reprod Biol 2007;132:171-6.

Tolcher MC, Holbert MR, Weaver AL, et al. Predicting cesarean delivery after induction of labour among nulliparous women at term. Obstet Gynecol 2015;126:1059-68.

Levine LD, Downes KL, Parry S, Elovitz MA, Sammel MD, Srinivas SK. A validated calculator to estimate risk of cesarean after an induction of labor with an unfavorable cervix. Am J Obstet Gynecol 2018;254:e1-254.e7.

Vrouenraets FP, Roumen FJ, Dehing CJ, van den Akker ES, Aarts MJ, Scheve EJ. Bishop score and risk of cesarean delivery after induction of labour in nulliparous women. Obstet Gynecol 2005;105:690-7.

Peregrine E, O’Brien P, Omar R, Jauniaux E. Clinical and ultrasound parameters to predict the risk of cesarean delivery after induction of labor. Obstet Gynecol 2006;107:227-33.

Rane SM, Guirgis RR, Higgins B, Nicolaides KH. Models for the prediction of successful induction of labor based on pre-induction sonographic measurement of cervical length. J Matern Fetal Neonatal Med 2005;17:315-22.

Bishop EH. Pelvic scoring for elective induction. Obstet Gynecol 1964;24:266-8.

Grobman WA, Lai Y, Landon MB, et al. Development of a nomogram for prediction of vaginal birth after cesarean delivery. Obstet Gynecol 2007;109:806-12.

Bleeker SE, Moll HA, Steyerberg EW, et al. External validation is necessary in prediction research: a clinical example. J Clin Epidemiol 2003;56:826-32.

Ware V, Raynor BD. Transvaginal ultrasonographic cervical measurement as a predictor of successful labor induction. Am J Obstet Gynecol 2000;182:1030-2.

Chandra S, Crane JM, Hutchens D, Young DC. Transvaginal ultrasound and digital examination in predicting successful labor induction. Obstet Gynecol 2001;98:2-6.

Ennen CS, Bofill JA, Magann EF, Bass JD, Chauhan SP, Morrison JC. Risk factors for cesarean delivery in preterm, term and post-term patients undergoing induction of labor with an unfavorable cervix. Gynecol Obstet Invest 2009;67:113-7.

Crane JM. Factors predicting labor induction success: a critical analysis. Clin Obstet Gynecol 2006;49:573-84.

Lange AP, Secher NJ, Westergaard JG, Skovgard I. Prelabor evaluation of inducibility. Obstet Gynecol 1982;60:137-47.