Risk factors for failed induction in nulliparous women.
OBJECTIVE
To identify risk factors for failed induction in nulliparous women.


METHODS
A retrospective cohort study of nulliparous women admitted for induction of labour (IOL). Identification of risk factors for failed IOL by comparing clinical characteristics of patients with a failed IOL defined as birth by caesarean section (LSCS) with those achieving vaginal birth.


RESULTS
During a 12 month episode, 400 nulliparous women had an IOL; of these 168 (42%) failed to deliver vaginally. Independent antenatal risk factors for failed IOL were higher maternal age (OR = 1.052 per additional year), being shorter (OR = 1.112 per cm less maternal height) and a lower cervical dilatation score (OR = 1.411 per lower cervical dilatation score). A longer active phase (OR = 1.004 per additional minute) was the only independent intrapartum risk factor for having a LSCS.


CONCLUSIONS
Maternal age, height and cervical dilatation are independent antepartum risk factors, while duration of active phase is the single independent intrapartum risk factor for a failed IOL. Increased maternal BMI was less of a risk factor than anticipated with increased risk for failed IOL, as independent risk factor, more or less restricted to the morbidly obese women.
Women and Children's Division, Lyell McEwin Hospital, University of Adelaide, Adelaide, Australia.
Femke
F
Frederiks
Shalem
S
Lee
Gus
G
Dekker
D000328:Adult; D015992:Body Mass Index; D002585:Cesarean Section / Q000706:statistics & numerical data; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007751:Labor, Induced / Q000009:adverse effects / Q000706:statistics & numerical data; D009767:Obesity, Morbid / Q000150:complications; D007744:Obstetric Labor Complications / Q000453:epidemiology / Q000209:etiology*; D010298:Parity / Q000502:physiology; D011247:Pregnancy; D012189:Retrospective Studies; D012307:Risk Factors; D017211:Treatment Failure; D055815:Young Adult