Obstet Gynecol Sci.  2015 Sep;58(5):346-352. 10.5468/ogs.2015.58.5.346.

Risk of cesarean section after induced versus spontaneous labor at term gestation

• Lee HR
• Kim MN
• You JY
• Choi SJ
• Oh SY
• Roh CR
• Kim JH

• KMID: 2058457
• DOI: http://doi.org/10.5468/ogs.2015.58.5.346

Abstract

OBJECTIVE
To investigate whether the cesarean section (CS) rate is increased in women whose labor was induced compared to those who had spontaneous labor at term pregnancy.
METHODS
A retrospective study was performed in women whose labor was either induced (induction group, n=497) or spontaneous (spontaneous group, n=878) at 37+0 to 41+6 weeks of gestation from January 2008 to June 2009. Maternal age, parity, body mass index (BMI), Bishop scores, gestational age, hypertension, diabetes, delivery mode, indications for CS, neonatal outcome were compared between the two groups. Multiple logistic regression analysis was used to examine the association between the CS rate and labor induction after adjusting for potential confounding variables.
RESULTS
CS (17.3% vs. 5.3%, P<0.001) and vacuum-assisted delivery (10.7% vs. 6.4%, P<0.001) rates were significantly higher in the induction group compared to the spontaneous group. The CS rate in the induction group was higher than the spontaneous group not only in nulliparous women (25.3% vs. 8.6%, P<0.001), but also in multiparous women (3.8% vs. 0.3%, P=0.002). However, after adjusting confounding factors, the higher CS rate was significantly associated with advanced maternal age, higher BMI, lower Bishop scores and nulliparity, with no demonstrable tie to labor induction. Neonatal outcome in the two groups were comparable.
CONCLUSION
Although CS rate was higher in women whose labor was induced than those who had spontaneous labor, this higher rate was associated with maternal age, BMI, Bishop scores and parity, but was not impacted by labor induction per se.

Keyword

Cesarean section; Labor induction; Spontaneous labor

MeSH Terms

Body Mass Index
Cesarean Section*
Confounding Factors (Epidemiology)
Female
Gestational Age
Humans
Hypertension
Logistic Models
Maternal Age
Parity
Pregnancy
Pregnancy*
Retrospective Studies

Figure

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  Fig. 1 Indications for labor induction in all subjects (A), in nulliparous women (B), and in multiparous women (C). DM, diabetes mellitus; SGA, small-for-gestational age; LGA, large-for-gestational age.

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  Fig. 2 Cesarean section (CS) rate by indication for labor induction. DM, diabetes mellitus; SGA, small-for-gestational age; LGA, large-forgestational age.

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  Fig. 3 Cesarean section (CS) rate by gestational age in (A) nulliparous women vs. multiparous women, and (B) in the spontaneous labor group vs. labor induction group.

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