Postterm with favorable cervix: is induction necessary?

doi:10.1016/S0301-2115(02)00243-9

European Journal of Obstetrics & Gynecology and Reproductive Biology

Volume 106, Issue 2, 10 February 2003, Pages 154-157

https://doi.org/10.1016/S0301-2115(02)00243-9 Get rights and content

Abstract

Objective: To study the cesarean rate between expectant management and immediate induction in the otherwise uncomplicated postterm pregnancy with favorable cervix. Study design: A total of 249 women with uncomplicated pregnancies at 41 weeks plus 3 days (290 days) with favorable cervix (Bishop score ≥6) were randomized to either expectant management (n=125) or immediate induction of labor (n=124). The women in the induction group were sent to labor ward for induction by artificial rupture of membranes (ARM) and/or oxytocin infusion. The women with expectant management had nonstress test (NST) and amniotic fluid index (AFI) performed once a week and twice a week after 43 weeks of gestation until spontaneous labor. Results: The cesarean rate was not different between expectant management and immediate induction (21.6% versus 26.6%; P=0.36). Ninety-five percent of the expectant group delivered within 1 week after enrollment, and all of them delivered within 9 days after randomization. Maternal and fetal complications in both groups were not different. There was also no difference in the mean birth weight (P=0.24) and the frequency of macrosomia (birth weight ≥4000 g) between the two groups (P=0.23). Conclusion: Cesarean section rate between expectant management and immediate induction in the otherwise uncomplicated postterm pregnancy with favorable cervix was not different. Due to the very low adverse perinatal outcome, both expectant management and immediate induction are acceptable.

Introduction

Postterm pregnancy is a common high-risk problem in obstetrics. The risks in postterm include marked increases in the perinatal morbidity and mortality [1]. In previous postterm studies comparing the expectant arm with induction arm, induction was initiated once the cervices became favorable [2], [3], [4], [5]. Although, meta-analysis demonstrates benefit of routine induction, most of the trials included either pregnant women with unfavorable cervix or those with both favorable and unfavorable cervix [6]. Subgroup analysis in the Cochrane database also compared cesarean section rate only in the pregnant women with Bishop score ≤6 [6]. Low-risk postterm women with favorable cervix are usually managed by induction of labor. However, there is not enough evidence to determine whether immediate induction is necessary.

The objective of this study was to determine the cesarean rate between expectant management and immediate induction in the otherwise uncomplicated postterm pregnancy with favorable cervix and to reveal the complications during the expectant period.

Section snippets

Materials and methods

This study was conducted from October 1998 to May 2000 at a university teaching hospital after being approved by the ethics committee. The study was a randomized trial comparing cesarean section rate between immediate induction and expectant management in otherwise uncomplicated postterm pregnancy with favorable cervix.

Results

A total of 250 low-risk postterm women with favorable cervix were enrolled in this study but one was excluded because of breech presentation. The remaining 249 patients, 125 were in the expectant management group and 124 were in the induction group.

Table 1 compares the maternal characteristics at the time of the randomization. There were no differences between treatment groups in the demographic variables. Most of the women (97%) were randomized at gestational age between 290 and 294 days. On

Discussion

Before the introduction of fetal surveillance, postterm pregnancy was associated with increasing perinatal morbidity and mortality [10]. Induction of labor was introduced as a means to reduce these events. In recent year, fetal surveillance techniques have offered some help in reducing the perinatal risks in postterm pregnancy. Previous studies have demonstrated that in the low-risk postterm pregnancy with unfavorable cervix, whether managed expectantly or immediate induction, the perinatal

Acknowledgements

This study was supported by Ramathibodi Hospital Research Grant no. 2/2542.

References (19)

D.C. Lagrew et al.
Management of postdate pregnancy
Am. J. Obstet. Gynecol.
(1986)
D.C. Dyson et al.
Management of prolonged pregnancy: induction of labor versus antepartum fetal testing
Am. J. Obstet. Gynecol.
(1987)
Y. Herabutya et al.
Prolonged pregnancy: the management dilemma
Int. J. Gynecol. Obstet.
(1992)
L. Rand et al.
Postterm induction of labor revisited
Obstet. Gynecol.
(2000)
The National Institute of Child Health and Human Development Network of Maternal-Fetal Medicine Units. A clinical trial...
P. BergsjØ et al.
Comparison of induced versus noninduced labor in postterm pregnancy: a randomized prospective study
Acta. Obstet. Gynecol. Scand.
(1989)
Crowley P. Interventions for preventing or improving the outcome of delivery at or beyond term (Cochrane Review). In:...
American College of Obstetricians and Gynecologists. Induction of labor. Technical Bulletin no. 217, December...
K.J. Shaw et al.
Selective labor induction in postterm patients: observations and outcomes
J. Reprod. Med.
(1992)

There are more references available in the full text version of this article.

Cited by (38)

Perinatal and maternal outcomes according to timing of induction of labour: A systematic review and meta-analysis
2023, European Journal of Obstetrics and Gynecology and Reproductive Biology
The risk of adverse perinatal and maternal outcomes increases with gestational age, and although induction of labour may reduce these risks, the optimal timing of induction remains unknown. We carried out a systematic review and meta-analysis, to determine the gestational age at which induction should be offered.
We searched Cochrane Central Register of Controlled Trials, Medline, and Embase databases from inception to July 2022, to identify randomised trials comparing induction of labour at or beyond 37′ weeks gestation with expectant management or delayed induction, and according to the gestational age at planned induction. We undertook random effects meta-analysis and pooled estimates as odds ratios with 95% confidence intervals. We assessed risk of bias of studies using the Cochrane Risk of Bias tool 2.0.
We included 44 trials (23,960 women and 22,191 offspring) from 1,839 citations in our meta-analysis. The odds of perinatal death (odds ratio 0.42, 95% confidence interval 0.22 to 0.81; 26 studies, 20,154 offspring), stillbirth (0.40, 0.16 to 0.98; 25 studies, 19,412 offspring), admission to neonatal intensive care unit (0.86, 0.78 to 0.96; 23 studies, 18,846 offspring), and caesarean section (0.90, 0.83 to 0.98; 40 studies, 23,616 women) were reduced in the induction of labour group compared to expectant management or delayed induction. The odds of admission to neonatal intensive care unit (0.82, 0.70 to 0.96; 6 studies, 9,316 offspring) were lower with induction of labour at 41 weeks compared to induction at or after 42 weeks’ gestation, and the odds of caesarean section were reduced with labour induction at 39 weeks’ compared to induction at or after 40 weeks’ (0.83, 0.74 to 0.93; 8 studies, 7,677 women). There were no significant differences in pregnancy outcomes by method of induction of labour.
Induction of labour compared to expectant management or delayed induction reduces the risk of adverse pregnancy outcomes, and the optimal timing may depend on the specific outcome of interest.
Timing induction of labour at 41 or 42 weeks? A closer look at time frames of comparison: A review
2018, Midwifery
Citation Excerpt :
Pooling these three trials showed no significant difference between IOL and EM (93/629 versus 106/629; RR 0.88; 95%CI 0.68–1.13). RCTs of Chanrachakul et al. (2003), Dyson et al. (1987), Henry (1969), James et al. (2001), Martin et al. (1989), NICHHD (1994), Augensen et al. (1987), Bergsjo et al. (1989), Herabutya (1992), Ocon (1997), Roach (1997) and Witter et al.(1987) were beyond 42 weeks (Table 3). There was no significant difference in the incidence of CS (222/1175 versus 237/1152; RR 0.92; 95%CI: 0.74–1.15).
Background: Postterm pregnancy is associated with increased perinatal risk. The WHO defines postterm pregnancy as a pregnancy at or beyond 42 weeks + 0 days, though currently labour is induced at 41 weeks in many settings. Guidelines on timing of labour induction are frequently based on the Cochrane systematic review ‘Induction of labour for improving birth outcomes for women at or beyond term’ in which is concluded that a policy of induction of labour is associated with fewer adverse perinatal outcome and fewer Caesarean sections. However, the included trials differed regarding the timing of induction, ranging from 39 to beyond 42 weeks while the upper limit of expectant management exceeded a gestational age of 42 weeks in most studies. Objective: to evaluate perinatal mortality, meconium aspiration syndrome and Caesarean section rate of trials comparing a policy of elective induction of labour and expectant management according to timeframes of comparison with a focus on studies within the 41–42 weeks’ timeframe. Design: Review. Methods: The systematic review of Cochrane was used as a starting point for assessing relevant trials and a search was performed for additional recent trials. We evaluated incidence and causes of perinatal mortality, incidence of meconium aspiration syndrome and Caesarean section according to three time frames of comparison. We pooled estimates and heterogeneity was tested. The quality of the included trials was assessed using the Quality Assessment Tool for Quantative Studies (EPHPP). Findings: In total 22 trials were included which had all different timeframes of comparison. Only one trial compared induction of labour at 41 weeks + 0–2 days with induction at 42 weeks + 0 days, three other trials compared induction of labour at 41 weeks + 0–6 days with induction at 42 weeks + 0–6 days. In 18 trials the comparison was outside the 41–42 weeks’ timeframe: in six trials induction was planned ≤ 40 weeks and in another 12 trials expectant management was beyond 43 weeks. The incidence of potentially gestational age associated perinatal mortality between 41 and 42 weeks was 0/2.444 [0%] (induction) versus 4/2.452 [0.16%] (expectant management), NNT 613; 95%CI 613 – infinite. Two trials in the timeframe of comparison 41–42 weeks were available for evaluation of meconium aspiration syndrome (6/554 (induction) versus 14/554 (expectant management), RR 0.44; 95%CI 0.17–1.16). Three trials in the timeframe 41–42 weeks could be evaluated for Caesarean section, with different inclusion criteria regarding Bishop score. There was no significant difference in the Caesarean section rate 93/629 (induction) versus 106/629 (expectant management), RR 0.88; 95%CI 0.68–1.13. Conclusion: Evidence is lacking for the recommendation to induce labour at 41 weeks instead of 42 weeks for the improvement of perinatal outcome. More studies comparing both timeframes with an adequate sample size are needed to establish the optimal timing of induction of labour in late-term pregnancies.
No. 214-Guidelines for the Management of Pregnancy at 41+0 to 42+0 Weeks
2017, Journal of Obstetrics and Gynaecology Canada
Citation Excerpt :
Women should be offered the option of membrane sweeping commencing at 38 to 41 weeks, following a discussion of risks and benefits (I-A). Nineteen trials randomizing women with uncomplicated pregnancies at 41 or more weeks' gestation to induction or expectant management with surveillance were identified.49–67 A recently published trial randomized women at 41 weeks and two days of gestation to induction or expectant management; however, the authors do not specify if the pregnancies are uncomplicated.68
To provide evidence-based guidelines for the management of pregnancy at 41+0 to 42+0 weeks.
Reduction of perinatal mortality associated with Caesarean section at 41+0 to 42+0 weeks of pregnancy.
The Medline database, the Cochrane Library, and the American College of Obstetricians and Gynecologists and the Royal College of Obstetricians and Gynecologists, were searched for English language articles published between 1966 and March 2007, using the following key words: prolonged pregnancy, post-term pregnancy, and postdates pregnancy. The quality of evidence was evaluated and recommendations were made according to guidelines developed by the Canadian Task Force on Preventive Health Care.
- 1.
  First trimester ultrasound should be offered, ideally between 11 and 14 weeks, to all women, as it is a more accurate assessment of gestational age than last menstrual period with fewer pregnancies prolonged past 41+0 weeks (I-A).
- 2.
  If there is a difference of greater than 5 days between gestational age dated using the last menstrual period and first trimester ultrasound, the estimated date of delivery should be adjusted as per the first trimester ultrasound (I-A).
- 3.
  If there is a difference of greater than 10 days between gestational age dated using the last menstrual period and second trimester ultrasound, the estimated date of delivery should be adjusted as per the second trimester ultrasound (I-A).
- 4.
  When there has been both a first and second trimester ultrasound, gestational age should be determined by the earliest ultrasound (I-A).
- 5.
  Women should be offered the option of membrane sweeping commencing at 38 to 41 weeks, following a discussion of risks and benefits (I-A).
- 6.
  Women should be offered induction at 41+0 to 42+0 weeks, as the present evidence reveals a decrease in perinatal mortality without increased risk of Caesarean section (I-A).
- 7.
  Antenatal testing used in the monitoring of the 41- to 42-week pregnancy should include at least a non-stress test and an assessment of amniotic fluid volume (I-A).
- 8.
  Each obstetrical department should establish guidelines dependent on local resources for scheduling of labour induction (I-A).
No. 214 - Guidelines for the management of pregnancy at 41+0 to 42+0 weeks
2017, Journal of Obstetrics and Gynaecology Canada
Fournir une directive clinique factuelle sur la prise en charge de la grossesse entre la 41^e+0 et la 42^e+0 semaine de gestation.
Baisse de la mortalité périnatale associée à la césarienne effectuée entre la 41^e+0 et la 42^e+0 semaine de gestation.
Des recherches ont été menées dans la base de données Medline, la Cochrane Library, ainsi qu’auprès du American College of Obstetricians and Gynecologists et du Royal College of Obstetricians and Gynecologists, afin d’en tirer les articles publiés en anglais entre 1966 et mars 2007, au moyen des mots clés suivants : prolonged pregnancy, post-term pregnancy et postdates pregnancy. La qualité des résultats a été évaluée et les recommandations ont été formulées conformément aux lignes directrices élaborées par le Groupe d’étude canadien sur les soins de santé préventifs.
- 1.
  L’exécution d’une échographie devrait être offerte au cours du premier trimestre (idéalement, entre la 11^e et la 14^e semaine de gestation) à toutes les femmes, puisqu’il s’agit d’un moyen de déterminer l’âge gestationnel plus précis que le recours à la date des dernières règles; l’utilisation de l’échographie du premier trimestre à cette fin donne, en effet, lieu à un nombre moindre de grossesses prolongées au-delà de 41+0 semaines (I-A).
- 2.
  Lorsque plus de cinq jours séparent l’âge gestationnel déterminé au moyen de la date des dernières règles et l’âge gestationnel déterminé au moyen de l’échographie du premier trimestre, la date prévue de l’accouchement devrait être modifiée en fonction de résultats de l’échographie du premier trimestre (I-A).
- 3.
  Lorsque plus de dix jours séparent l’âge gestationnel déterminé au moyen de la date des dernières règles et l’âge gestationnel déterminé au moyen de l’échographie du deuxième trimestre, la date prévue de l’accouchement devrait être modifiée en fonction de résultats de l’échographie du deuxième trimestre (I-A).
- 4.
  Lorsque l’on dispose d’échographies tant du premier que du deuxième trimestre, l’âge gestationnel devrait être déterminé en fonction des résultats de la première échographie (I-A).
- 5.
  Les femmes devraient se voir offrir l’option du décollement des membranes à partir de la période se situant entre la 38^e; et la 41^e semaine de gestation, à la suite d’une discussion sur les risques; et avantages d’une telle intervention (I-A).
- 6.
  Les femmes devraient se voir offrir un déclenchement entre la 41^e+0 et la 42^e+0 semaine de gestation, puisque les données actuelles indiquent que cette pratique entraîne une baisse du taux de mortalité périnatale sans hausse du risque de césarienne (I-A).
- 7.
  Le dépistage prénatal utilisé dans le cadre de la surveillance des grossesses se situant entre la 41^e et la 42^e semaine de gestation devrait comprendre au moins un examen de réactivité fœtale et une évaluation du volume de liquide amniotique (I-A).
- 8.
  Tous les services d’obstétrique devraient, en fonction de leurs ressources locales, formuler des lignes directrices quant à la planification du déclenchement du travail (I-A).
Induction of labor compared to expectant management in low-risk women and associated perinatal outcomes
2012, American Journal of Obstetrics and Gynecology
We sought to examine the association of labor induction and perinatal outcomes.
This was a retrospective cohort study of low-risk nulliparous women with term, live births. Women who had induction at a given gestational age (eg, 39 weeks) were compared to delivery at a later gestation (eg, 40, 41, or 42 weeks).
Compared to delivery at a later gestational age, those induced at 39 weeks had a lower risk of cesarean (adjusted odds ratio [aOR], 0.90; 95% confidence interval [CI], 0.88–0.91) and labor dystocia (aOR, 0.88; 95% CI, 0.84–0.94). Their neonates had lowered risk of having 5-minute Apgar <7 (aOR, 0.81; 95% CI, 0.72–0.92), meconium aspiration syndrome (aOR, 0.30; 95% CI, 0.19–0.48), and admission to neonatal intensive care unit (aOR, 0.87; 95% CI, 0.78–0.97). Similar findings were seen for women who were induced at 40 weeks compared to delivery later.
Induction of labor in low-risk women at term is not associated with increased risk of cesarean delivery compared to delivery later.
Elective termination versus expectant management in prolonged pregnancy: A prospective study of 200 pregnant women
2010, Progresos de Obstetricia y Ginecologia
Comparar la finalización electiva de la gestación prolongada versus el manejo expectante, en gestaciones de bajo riesgo obstétrico.
Ensayo clínico controlado y aleatorizado entre actuaciones activas y expectantes, sobre una muestra de 200 mujeres con gestación prolongada de bajo riesgo obstétrico entre febrero de 2003 y junio de 2005 en el Hospital Universitario Materno-Infantil de Canarias.
El grupo estudio está formado por 200 pacientes - 102 del grupo activa y 98 del grupo expectante -. No se encontraron diferencias epidemiológicas entre ambos grupos. El parto no fue inducido en un porcentaje de gestantes significativamente superior en el grupo activa frente al grupo expectante (51% vs 35,7%, p = 0,02; OR 0,53 [CI 95% 0,3-0,94]), es decir, el número de inducciones es significativamente superior en el grupo de manejo expectante. Una tasa significativamente menor de gestantes del grupo activa presentó líquido amniótico meconial durante la dilatación (15,7% vs 28,6% p = 0,02; OR 0,47 [IC 95% 0,23-0,93]). No existen diferencias significativas con relación al tipo de parto, no obstante el porcentaje de intervención cesárea fue marcadamente inferior en el grupo activa frente al grupo expectante ([12,7% vs 18,4%, p = 0,3; OR 0,65 [IC 95% 0.3-1.41]). Los resultados perinatales no muestran diferencias significativas entre ambos grupos.
La finalización electiva en el semana 42, en gestaciones de bajo riesgo obstétrico con condiciones cervicales desfavorables, parece reducir la tasa de cesáreas sin comprometer los resultados perinatales.
To compare elective termination versus expectant management in low-risk prolonged pregnancy.
We performed a controlled randomized clinical trial comparing the results of active and expectant approaches in the management of low-risk prolonged pregnancy in a sample of 200 women between February 2003 and June 2005 at the Maternity Ward of the Canary Islands University Hospital.
The study group consisted of 200 patients. There were 102 in the active management group and 98 in the expectant management group. No between-group epidemiologic differences were found. Labor was not induced in a significantly higher proportion of patients in the active than in the expectant group [51% vs 35.7%, p = 0.02; OR 0.53 (95% CI 0.3-0.94)] i.e. the induction rate was significantly higher in the expectant group. The proportion of patients with meconium-stained amniotic fluid during labor was significantly lower in the active management group [15.7% vs 28.6% p = 0.02; OR 0.47 (95% CI 0.23-0.93)]. No significant differences were found in the type of delivery, although the proportion of cesarean sections was noticeably lower in the active management than in the expectant management group [(12.7% vs 18.4%, p = 0.3; OR 0.65 (95% CI 0.3-1.41)]. No significant differences were found in perinatal outcomes between the two groups.
Elective termination of low-risk pregnancies with unfavorable cervical findings at week 42 seems to reduce the rate of cesarean section without impairing perinatal outcome.

View all citing articles on Scopus

View full text

Postterm with favorable cervix: is induction necessary?

Abstract

Introduction

Section snippets

Materials and methods

Results

Discussion

Acknowledgements

Am. J. Obstet. Gynecol.

Am. J. Obstet. Gynecol.

Int. J. Gynecol. Obstet.

Obstet. Gynecol.

Comparison of induced versus noninduced labor in postterm pregnancy: a randomized prospective study

Acta. Obstet. Gynecol. Scand.

Selective labor induction in postterm patients: observations and outcomes

J. Reprod. Med.