Elective induction compared with expectant management in nulliparous women with a favorable cervix

Methods for the induction of labor: efficacy and safety

This review assessed the efficacy and safety of pharmacologic agents (prostaglandins, oxytocin, mifepristone, hyaluronidase, and nitric oxide donors) and mechanical methods (single- and double-balloon catheters, laminaria, membrane stripping, and amniotomy) and those generally considered under the rubric of complementary medicine (castor oil, nipple stimulation, sexual intercourse, herbal medicine, and acupuncture). A substantial body of published reports, including 2 large network meta-analyses, support the safety and efficacy of misoprostol (PGE1) when used for cervical ripening and labor induction. Misoprostol administered vaginally at doses of 50 μg has the highest probability of achieving vaginal delivery within 24 hours. Regardless of dosing, route, and schedule of administration, when used for cervical ripening and labor induction, prostaglandin E2 seems to have similar efficacy in decreasing cesarean delivery rates. Globally, although oxytocin represents the most widely used pharmacologic agent for labor induction, its effectiveness is highly dependent on parity and cervical status. Oxytocin is more effective than expectant management in inducing labor, and the efficacy of oxytocin is enhanced when combined with amniotomy. However, prostaglandins administered vaginally or intracervically are more effective in inducing labor than oxytocin. A single 200-mg oral tablet of mifepristone seems to represent the lowest effective dose for cervical ripening. The bulk of the literature assessing relaxin suggests this agent has limited benefit when used for this indication. Although intracervical injection of hyaluronidase may cause cervical ripening, the need for intracervical administration has limited the use of this agent. Concerning the vaginal administration of nitric oxide donors, including isosorbide mononitrate, isosorbide, nitroglycerin, and sodium nitroprusside, the higher incidence of side effects with these agents has limited their use. A synthetic hygroscopic cervical dilator has been found to be effective for preinduction cervical ripening. Although a pharmacologic agent may be administered after the use of the synthetic hygroscopic dilator, in an attempt to reduce the interval to vaginal delivery, concomitant use of mechanical and pharmacologic methods is being explored. Combining the use of a single-balloon catheter with dinoprostone, misoprostol, or oxytocin enhances the efficacy of these pharmacologic agents in cervical ripening and labor induction. The efficacy of single- and double-balloon catheters in cervical ripening and labor induction seems similar. To date, the combination of misoprostol with an intracervical catheter seems to be the best approach when balancing delivery times with safety. Although complementary methods are occasionally used by patients, given the lack of data documenting their efficacy and safety, these methods are rarely used in hospital settings.

Challenges in timing and mode of delivery in morbidly obese women

Globally obesity is increasing especially in the reproductive age group. Pregnant women with obesity have higher complication and intervention rates. They are also at increased risk of stillbirth and intrapartum complications. Although organisations like NICE, RCOG, ACOG and WHO have published guidelines and recommendations on care of pregnant women with obesity the evidence from which Grade A recommendations can be made on timing and how to deliver is limited. The current advice is therefore to have discussions with the woman on risks to help her make an informed decision about timing, place, and mode of delivery. Obesity is an independent risk factor for pregnancy complications including diabetes, hypertension and macrosomia. In those with these complications, the timing of delivery is often influenced by the severity of the complication. As an independent factor, population based observational studies in obese women have shown an increase in the risk of stillbirth. This risk increases linearly with weight from overweight through to class II obesity, but then rises sharply in those with class III obesity by at least 10-fold beyond 42 weeks when compared to normal weight women. This risk of stillbirth is notably higher in obese women from 34 weeks onwards compared to normal weight women. One modifiable risk factor for stillbirth as shown from various cohorts of pregnant women is prolonged pregnancy. Research has linked obesity to prolonged pregnancy. Although the exact mechanism is yet unknown some have linked this to maternal dysregulation of the hypothalamic pituitary adrenal axis leading to hormonal imbalance delaying parturition. For these women the two dilemmas are when and how best to deliver. In this review, we examine the evidence and make recommendations on the timing and mode of delivery in women with obesity. For class I obese women there are no differences in outcome with regards to timing and mode of delivery when compared to lean weight women. However, for class II and III obesity, planned induction or caesarean sections may be associated with a lower perinatal morbidity and mortality although this may be associated with an increased in maternal morbidity especially in class III obesity. Studies have shown that delivery by 39 weeks is associated with lower perinatal mortality compared to delivering after in these women. On balance the evidence would favour planned delivery (induction or caesarean section) before 40 weeks of gestation. In the morbidly obese, apart from the standard lower transverse skin incision for CS, there is evidence that a supraumbilical transverse incision may reduce morbidity but is less cosmetic. Irrespective of the option adopted, it is important to discuss the pros and cons of each.

Predicting Spontaneous Labor beyond 39 Weeks among Low-Risk Expectantly Managed Pregnant Patients

OBJECTIVES

The aim of the study was to identify the characteristics associated with spontaneous labor onset in pregnant patients undergoing expectant management at greater than 39 weeks' gestation and delineate perinatal outcomes associated with spontaneous labor compared with labor induction.

STUDY DESIGN

This was a retrospective cohort study of singleton pregnancies at ≥390/7 weeks' gestation delivered at a single center in 2013. The exclusion criteria were elective induction, cesarean delivery or presence of a medical indication for delivery at 39 weeks, more than one prior cesarean delivery, and fetal anomaly or demise. We evaluated prenatally available maternal characteristics as potential predictors of the primary outcome-spontaneous labor onset. Multivariable logistic regression was used to generate two parsimonious models: one with and one without third trimester cervical dilation. We also performed sensitivity analysis by parity and timing of cervical examination, and compared the mode of delivery and other secondary outcomes between patients who went into spontaneous labor and those who did not.

RESULTS

Of 707 eligible patients, 536 (75.8%) attained spontaneous labor and 171 (24.2%) did not. In the first model, maternal body mass index (BMI), parity, and substance use were identified as the most predictive factors. Overall, the model did not predict spontaneous labor (area under the curve [AUC]: 0.65; 95% confidence interval [CI]: 0.61-0.70) with high accuracy. The addition of third trimester cervical dilation in the second model did not significantly improve labor prediction (AUC: 0.66; 95% CI: 0.61-0.70; p = 0.76). These results did not differ by timing of cervical examination or parity. Patients admitted in spontaneous labor had lower odds of cesarean delivery (odds ratio [OR]: 0.33; 95% CI: 0.21-0.53) and neonatal intensive care unit (NICU) admission (OR: 0.38; 95% CI: 0.15-0.94). Other perinatal outcomes were similar between the groups.

CONCLUSION

Maternal characteristics did not predict spontaneous labor onset at ≥39 weeks' gestation with high accuracy. Patients should be counseled on the challenges of labor prediction regardless of parity and cervical examination, outcomes if spontaneous labor does not occur, and benefits of labor induction.

KEY POINTS

· Majority of patients will attain spontaneous labor at ≥39 weeks.. · Maternal characteristics do not predict labor at ≥39 weeks.. · Spontaneous labor has associated lower perinatal risks.. · A shared decision model should be utilized in counseling patients who may choose expectant management..

Impact of labor induction at 39 weeks gestation compared with expectant management on maternal and perinatal morbidity among a cohort of low-risk women

OBJECTIVE

To determine maternal and perinatal outcomes after induction of labor (IOL) at 39 weeks compared with expectant management.

METHODS

This is a retrospective national cohort study from the National Center for Health Statistics birth database. The study included singleton, low-risk pregnancies with a non-anomalous fetus delivered at 39-42 weeks gestation between 2015 and 2018. Maternal outcomes available included chorioamnionitis (Triple I), blood transfusion, intensive care unit (ICU) admission, uterine rupture, cesarean delivery (CD), and cesarean hysterectomy. Fetal and infant outcomes included stillbirth, 5-min Apgar ≤3, prolonged ventilation, seizures, ICU admission, and death within 28 days. We compared women undergoing IOL at 39 weeks to those managed expectantly. Non-adjusted and adjusted relative risks (aRRs) were estimated using multivariate log-binomial regression analysis.

RESULTS

There were 15,900,956 births available for review of which 5,017,524 met inclusion and exclusion criteria. For the maternal outcomes, the IOL group was less likely to require a CD (aRR 0.880; 95% CI [0.874-0.886]; p value < .01) or develop Triple I (aRR 0.714; 95% CI [0.698-0.730]; p value < .01) but demonstrated a small increase in the cesarean hysterectomy rate (aRR 1.231; 95% CI [1.029-1.472]; p value < .01). Among perinatal outcomes, the stillbirth rate (aRR 0.195; 95% CI [0.153-0.249]; p value < .01), 5-min Apgar ≤3 (aRR 0.684; 95% CI [0.647-0.723]; p value < .01), prolonged ventilation (aRR 0.840; 95% CI [0.800-0.883]; p value < .01), neonatal intensive care (NICU) admission (aRR 0.862; 95% CI [0.849-0.875]; p value < .01) were lower after 39 week IOL compared with expectant management. There were no differences in risk for neonatal seizures (aRR 0.848; 95% CI [0.718-1.003]; p value 0.011) or death (aRR 1.070; 95% CI [0.722-1.586]; p value 0.660).

CONCLUSIONS

IOL at 39 weeks of gestation in a low-risk cohort is associated with a lower risk of CD and maternal infection, stillbirth, and lower neonatal morbidity. There was no effect on the risk for neonatal seizures or death.

Outcomes of Elective Induction of Labor versus Expectant Management among Obese Women at ≥39 Weeks

OBJECTIVE

Maternal obesity is associated with many adverse obstetric outcomes including cesarean delivery. It is unclear whether induction of labor can reduce these risks. Previous studies report conflicting results on the outcomes of elective induction of labor among obese women. This study aimed to compare maternal and neonatal outcomes between obese women undergoing elective induction of labor and those undergoing expectant management at ≥39 weeks.

STUDY DESIGN

This was a retrospective cohort study from the Consortium on Safe Labor of obese women (defined by prepregnancy body mass index≥ 30kg/m²) with singleton gestations at ≥39 weeks without medical comorbidities from 2002 through 2008. Women scheduled for medically indicated induction of labor were excluded. The primary outcome of cesarean delivery was compared between obese women undergoing elective induction of labor and expectant management during 39th, 40th, and 41st weeks using univariable and multivariable analyses, stratifying by parity.

RESULTS

In all, 7,298 nulliparous and 9,789 parous women were eligible for analysis. After controlling for potential confounders, elective induction of labor during 39th week in nulliparous and parous women was associated with lower odds of cesarean delivery (39.1 vs. 41.6%, adjusted odds ratio [OR]: 0.47, 95% confidence interval [CI]: 0.30-0.74 for nulliparous and 5.5 vs. 10.1%, adjusted OR: 0.34, 95% CI: 0.20-0.61 for parous women) compared with expectant management. Elective induction of labor during 40th and 41st weeks was not associated with lower odds of cesarean delivery. In addition, macrosomia was reduced in nulliparous women undergoing elective induction of labor during the 40th week (12.1 vs. 18.5%, adjusted OR: 0.56, 95% CI: 0.35-0.87) and in parous women undergoing elective induction of labor during 39th (11.6 vs. 17.6%, adjusted OR: 0.50, 95% CI: 0.38-0.66) and 40th weeks (16.4 vs. 22.2%, adjusted OR: 0.53, 95% CI: 0.36-0.78).

CONCLUSION

Elective induction of labor at 39 weeks, when compared with expectant management, was associated with lower cesarean deliveries in obese nulliparous and parous women.

Induction of labor in continuing pregnancies

This chapter aims to provide an evidence-based approach to cervical-ripening methods and induction of labor in high-, middle-, and low-income countries. We will review the epidemiology of induction and will also review pharmacological and mechanical methods of cervical-ripening as well as oxytocin for induction. Lastly, we will review current guidelines of when to determine an induction to be failed.

Neonatal and Maternal Adverse Outcomes Among Low-Risk Parous Women at 39-41 Weeks of Gestation

OBJECTIVE

To compare the composite neonatal or maternal adverse outcome among low-risk, parous women at 39-41 weeks of gestation.

METHODS

This was a retrospective cohort study using the U.S. vital statistics data sets (2012-2016). We evaluated low-risk parous women with nonanomalous singleton gestations who delivered at 39, 40, or 41 weeks of gestation (as reported in completed weeks, eg, 39 weeks includes 39 0/7-39 6/7 weeks of gestation). The primary outcome, the composite neonatal adverse outcome, included any of the following: Apgar score less than 5 at 5 minutes, assisted ventilation for longer than 6 hours, neonatal seizure, or neonatal mortality. The secondary outcome, the composite maternal adverse outcome, included any of the following: intensive care unit admission, blood transfusion, uterine rupture, or unplanned hysterectomy. We used multivariable Poisson regression analyses to estimate the association between gestational age and adverse outcome (using adjusted relative risks [aRR] and 95% CI).

RESULTS

Of 19.9 million live births during the study period, 5.4 million (27.1%) met inclusion criteria. Among them, 54.4% delivered at 39 weeks of gestation, 35.7% at 40 weeks, and 9.9% at 41 weeks. The overall rate of the composite neonatal adverse outcome was 4.86 per 1,000 live births. The risk of the composite neonatal adverse outcome was higher for those delivered at 40 (aRR 1.18; 95% CI 1.15-1.22) and 41 (aRR 1.59; 95% CI 1.53-1.65) weeks of gestation when compared with 39 weeks. The overall rate of the composite maternal adverse outcome was 2.31 per 1,000 live births. The risk of the composite maternal adverse outcome was also significantly higher with delivery at 40 (aRR 1.15; 95% CI 1.11-1.19) and 41 weeks of gestation (aRR 1.50; 95% CI 1.42-1.58) than at 39 weeks.

CONCLUSION

Though only modestly, the rates of the composite neonatal and maternal adverse outcomes increase, from 39 through 41 weeks of gestation, among low-risk parous women.

Elective Induction at 39 Weeks of Gestation and the Implications of a Large, Multicenter, Randomized Controlled Trial

On August 8, 2018, Grobman et al published the findings from the ARRIVE (A Randomized Trial of Induction Versus Expectant Management) trial, a large randomized controlled trial of elective induction of labor in nulliparous women at 39 weeks of gestation compared with expectant management. Conducted by the Eunice Kennedy Shriver National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network, the trial found there was no difference between the two groups in the primary outcome, a composite of neonatal morbidity. Also, there was a reduction in rates of cesarean delivery and hypertensive disorders of pregnancy in the elective induction group. The topic of elective induction has been of interest to clinicians for decades, and research has yielded inconsistent results in the past. This trial offers the best evidence thus far to address this complex issue. Our objective is to briefly review the history and literature regarding elective induction of labor, discuss the recently published ARRIVE trial, and consider its implications on clinical practice and health policy.

Elective induction of labor at 39 weeks compared with expectant management: a meta-analysis of cohort studies

BACKGROUND

Elective induction of labor at 39 weeks among low-risk nulliparous women has reduced the chance of cesarean and other adverse maternal and perinatal outcomes in a randomized trial, although its clinical effectiveness in nonresearch settings remains uncertain.

OBJECTIVE

To perform a systematic review of observational studies that compared elective induction of labor at 39 weeks among nulliparous women with expectant management and to use meta-analytic techniques to estimate the association of elective induction with cesarean delivery, as well as other maternal and perinatal outcomes.

STUDY DESIGN

Studies were eligible for this meta-analysis only if they: (1) were observational; (2) compared women undergoing labor induction at 39 weeks with women undergoing expectant management beyond that gestational age; (3) included women in the induction group only if they had no other indication for labor induction at 39 weeks; and (4) provided data specifically for nulliparous women. The predefined primary outcome was cesarean delivery, and secondary outcomes representing other maternal and perinatal morbidities also were evaluated. Outcome data from different studies were combined to estimate pooled relative risks with 95% confidence intervals using random-effects models.

RESULTS

Of 375 studies identified by the initial search, 6 cohort studies, which included 66,019 women undergoing elective labor induction at 39 weeks and 584,390 undergoing expectant management, met inclusion criteria. Elective induction of labor at 39 weeks was associated with a significantly lower frequency of cesarean delivery (26.4% vs 29.1%; relative risk, 0.83; 95% confidence interval, 0.74-0.93), as well as of peripartum infection (2.8% vs 5.2%; relative risk, 0.53; 95% confidence interval, 0.39-0.72). Neonates of women in the induction group were less likely to have respiratory morbidity (0.7% vs 1.5%; relative risk, 0.71; 95% confidence interval, 0.59-0.85); meconium aspiration syndrome (0.7% vs 3.0%; relative risk, 0.49; 95% confidence interval, 0.26-0.92); and neonatal intensive care unit admission (3.5% vs 5.5%; relative risk, 0.80; 95% confidence interval, 0.72-0.88). There also was a lower risk of perinatal mortality (0.04% vs 0.2%; relative risk, 0.27; 95% confidence interval, 0.09-0.76).

CONCLUSION

This meta-analysis of 6 cohort studies demonstrates that elective induction of labor at 39 weeks, compared with expectant management beyond that gestational age, was associated with a significantly lower risk of cesarean delivery, maternal peripartum infection, and perinatal adverse outcomes, including respiratory morbidity, intensive care unit admission, and mortality.

SMFM Statement on Elective Induction of Labor in Low-Risk Nulliparous Women at Term: the ARRIVE Trial

A Randomized Trial of Induction Versus Expectant Management (ARRIVE) was conducted by the Eunice Kennedy Shriver National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network from March 2014 to August 2017.This large multicenter, unmasked, randomized controlled trial was performed to test the hypothesis that elective IOL at 39 weeks of gestation, compared with expectant management among low-risk nulliparous women, reduces the risk of a composite outcome of perinatal death or severe neonatal morbidity. Nulliparous women with reliable dating and no obstetric or medical complications were eligible, regardless of favorability of cervical examination. The purpose of this document is to review the findings of the recent randomized trial and to provide guidance for implementation of the study findings.

A conceptual framework for the impact of obesity on risk of cesarean delivery

Cesarean deliveries accounted for 32.2% of nearly 4 million births in the United States in 2014. Obesity affects a third of reproductive-age women and is associated with worse cesarean delivery outcomes. Studies have shown that increasing maternal body mass index correlates linearly with cesarean delivery rates, but little is known about the potential mediating and moderating mechanisms. Thus, a conceptual framework for understanding how obesity correlates with risk of cesarean delivery is crucial to determining safe ways to reduce the cesarean delivery rate among obese gravidas. Based on an extensive review and synthesis of the literature, we present a conceptual framework that posits how obesity may operate through several pathways to lead to a cesarean delivery. Our framework explores the complexity of obesity as an exposure that operates through potential mediating pathways, a moderator of cesarean delivery risk, and a covariate with other cesarean delivery risk factors. Among nulliparas, obesity appears to operate through 3 main proximal mediating mechanisms to increase risk of cesarean delivery including: (1) preexisting comorbidities and obstetric complications; (2) a slower progression of first-stage labor, potentially increasing the risk of cesarean delivery secondary to failure to progress; and (3) a prolongation of pregnancy, which is associated with risk of maternal postdates. For multiparas, a fourth proximal mediator of prior uterine scar may also increase cesarean delivery risk. Distal mediating mechanisms, which operate through one of the proximal mechanisms, may include an induction of labor or planned prelabor cesarean delivery. Obesity may also moderate the likelihood of cesarean delivery by interacting with clinician-level or hospital-level factors. Future research should assess the validity of this framework and seek to understand the relative contributions of each potential pathway between obesity and cesarean delivery. This will allow for evidence-based recommendations to reduce preventable cesareans among obese women by targeting modifiable mediators and moderators of the relationship between obesity and increased risk of cesarean delivery.

Elective induction of labor at 39 weeks among nulliparous women: The impact on maternal and neonatal risk

Objective

Optimal management of pregnancies at 39 weeks gestational age is unknown. Therefore, we sought to perform a comparative effectiveness analysis of elective induction of labor (eIOL) at 39 weeks among nulliparous women with non-anomalous singleton, vertex fetuses as compared to expectant management (EM) which included IOL for medical or obstetric indications or at 41 weeks in undelivered mothers.

Materials and methods

A Monte Carlo micro-simulation model was constructed modeling two mutually exclusive health states: eIOL at 39 weeks, or EM with IOL for standard medical or obstetrical indications or at 41 weeks if undelivered. Health state distribution probabilities included maternal and perinatal outcomes and were informed by a review of the literature and data derived from the Consortium of Safe Labor. Analyses investigating preferences for maternal versus infant health were performed using weighted utilities. Primary outcome was determining which management strategy posed less maternal and neonatal risk. Secondary outcomes were rates of cesarean deliveries, maternal morbidity and mortality, stillbirth, neonatal morbidity and mortality, and preferences regarding the importance of maternal and perinatal health.

Results

A management strategy of eIOL at 39 weeks resulted in less maternal and neonatal risk as compared to EM with IOL at 41 weeks among undelivered patients. Cesarean section rates were higher in the EM arm (35.9% versus 13.9%, p<0.01). When analysis was performed only on patients with an unfavorable cervix, 39 week eIOL still resulted in fewer cesarean deliveries as compared to EM (8.0% versus 26.1%, p<0.01). There was no statistical difference in maternal mortality (eIOL 0% versus EM 0.01%, p = 0.32) but there was an increase in maternal morbidity among the EM arm (21.2% versus 16.5, p<0.01). There were more stillbirths (0.13% versus 0%, p<0.0003), neonatal deaths (0.25% versus 0.12%, p< 0.03), and neonatal morbidity (12.1% versus 9.4%, p<0.01) in the EM arm as compared to the eIOL arm. Preference modeling revealed that 39 week eIOL was favored over EM.

Conclusions and relevance

Mathematical modeling revealed that eIOL at 39 weeks resulted in lower population risks as compared to EM with induction of labor at 41 weeks. Specifically, eIOL at 39 weeks resulted in a lower cesarean section rate, lower rates of maternal morbidity, fewer stillbirths and neonatal deaths, and lower rates of neonatal morbidity.

[To the question of elective induction of labor at 39 weeks of gestation, the answer lies in the question]

The goal of induction of labor is to achieve vaginal delivery when the benefits of expeditious delivery outweigh the risks of continuing the pregnancy. In order to correctly understand the problematic of the elective induction of labor at 39 weeks of gestation (WG), two questions must be raised. (i) What is the perinatal mortality evolution according the gestational age at delivery? All the most recent and methodologically well-conducted studies are convergent: they show that the fetal mortality risk exceeds the perinatal/infant (during the first year of life) mortality risk from 39 WG. The benefit/risk balance related to the expectant management is therefore reversed from 39 WG in favor of the elective induction of labor when the considered issue is the perinatal mortality. (ii) What are the associated risks with elective induction of labor? While some observational studies suggested that the elective induction of labor after 37 WG was associated with an increased risk of cesarean sections, these studies presented a major methodological bias: an error in the control group selection. Indeed, the control group consisted of women in spontaneous labor, whereas the appropriate comparison group must be an expectant management group. Several large cohort studies using a rigorous methodology have shown that elective induction of labor at 39 WG reduces the cesarean section risk compared to an expectant management. Three systematic reviews with meta-analysis of randomized controlled trials comparing induction of labor with expectant management were published: two showed that the cesarean section risk was lowered with the induction of labor compared to an expectant management and the third that the cesarean section rates were similar. Finally, the most recent randomized controlled trial, published in 2016, showed no significant difference between the 2 arms in the cesarean section rate. In all, the most recent literature data, free from comparative bias, show that elective induction of labor at term is associated with a significant reduction in the cesarean section risk and perinatal morbidity and mortality compared to an expectant management.

Induction of labor versus expectant management of large-for-gestational-age infants in nulliparous women

Background

There is no apparent consensus on obstetric management, i.e., induction of labor or expectant management of women with suspected large-for-gestational-age (LGA)-fetuses.

Methods and findings

To further examine the subject, a nationwide population-based cohort study from the Swedish Medical Birth Register in nulliparous non-diabetic women with singleton, vertex LGA (>90^th centile) births, 1992–2013, was performed. Delivery of a live-born LGA infant induced at 38 completed weeks of gestation in non-preeclamptic pregnancies, was compared to those of expectant management, with delivery at 39, 40, 41, or 42 completed weeks of gestation and beyond, either by labor induction or via spontaneous labor. Primary outcome was mode of delivery. Secondary outcomes included obstetric anal sphincter injury, 5-minute Apgar<7 and birth injury. Multivariable logistic regression analysis was performed to control for potential confounding. We found that among the 722 women induced at week 38, there was a significantly increased risk of cesarean delivery (aOR = 1.44 95% CI:1.20–1.72), compared to those with expectant management (n = 44 081). There was no significant difference between the groups in regards to risk of instrumental vaginal delivery (aOR = 1.05, 95% CI:0.85–1.30), obstetric anal sphincter injury (aOR = 0.81, 95% CI:0.55–1.19), nor 5-minute Apgar<7 (aOR = 1.06, 95% CI:0.58–1.94) or birth injury (aOR = 0.82, 95% CI:0.49–1.38). Similar comparisons for induction of labor at 39, 40 or 41 weeks compared to expectant management with delivery at a later gestational age, showed increased rates of cesarean delivery for induced women.

Conclusions

In women with LGA infants, induction of labor at 38 weeks gestation is associated with increased risk of cesarean delivery compared to expectant management, with no difference in neonatal morbidity.

Cervical Evaluation: From Ancient Medicine to Precision Medicine

Since ancient times, cervical assessment for predicting timing of delivery has relied primarily on digital (subjective) assessment of dilatation, softening, and length. To date, transvaginal ultrasound cervical length is the only one of these parameters that meets criteria for a biomarker; no objective, quantitative measure of cervical dilatation or softening has gained clinical acceptance. This review discusses how the cervix has been assessed from ancient times to the present day and how a precision medicine approach could improve understanding of not only the cervix, but also parturition in general.

Outcome of Induction and Associated Factors among Term and Post-Term Mothers Managed at Jimma University Specialized Hospital: A Two Years' Retrospective Analysis

BACKGROUND

Induction of labor using oxytocin is a routine procedure in obstetrics used for vaginal delivery of gravid uterus. The purpose of this study was to analyze outcome of induction with oxytocin and associated factors among mothers who delivered at term and post-term in Jimma University Specialized Hospital, Southwest Ethiopia.

METHODS

A facility based cross-sectional study was conducted on records of 280 laboring mothers who delivered at term and post-term after induction with oxytocin from September 1(st), 2009 to August 31(st), 2011. The data were extracted using checklist and analyzed using SPSS windows version 16.0. The level of significance to declare relationship between the dependent and independent variables was set at p< 0.05.

RESULTS

Mean maximum oxytocin levels used until vaginal delivery and at time of diagnosis of failed induction were 55.0 ± 29.8 and 89.7± 11.6 miu/min respectively. Mean time elapsed from initiation of induction with oxytocin to vaginal delivery and till diagnosis of failed induction were 6:10 ± 3:09 and 9:57± 2:01 hours respectively. Failed induction was diagnosed in 21.4% of the mothers. Primigravidity, unfavorable and intermediate Bishop Scores determined at admission were found to be predictors of failed induction.

CONCLUSION

High rate of failed induction and high level of oxytocin use were found. Preparation of the cervix before commencing induction in primigravid women is recommended to improve success of induction with the current protocol.

Mode of delivery in nulliparous women with gestational hypertension undergoing early term induction of labor

OBJECTIVE

To evaluate perinatal outcomes in nulliparous women undergoing induction of labor for gestational hypertension at term.

STUDY DESIGN

Retrospective cohort study of nulliparous women with gestational hypertension undergoing induction of labor ≥37 weeks. Mode of delivery and perinatal outcomes were compared for women who delivered at 37^0-6/7, 38^0-6/7, and ≥39^0/7 weeks gestation.

RESULTS

The cohort included 320 women: 67 (21%) at 37^0-6/7, 76 (24%) at 38^0-6/7, and 177 (55%) at ≥39^0/7. There was no increase in cesarean delivery (CD) in women delivering earlier, with 26.9% (37^0-6/7), 19.7% (38^0-6/7) and 29.9% (≥39^0/7) requiring CD (p values = 0.39). Compared to ≥39 weeks, composite maternal morbidity was lowest in women delivering at 38^0-6/7 (adjusted odds ratio [aOR] 0.45, 95% confidence interval (CI) 0.24-0.84). Composite neonatal morbidity was similar among the groups. When compared to women delivering at ≥39^0/7 weeks, women delivered at 38^0-6/7 were less likely to experience any adverse maternal or neonatal outcome (aOR 0.50, 95% CI 0.28-0.90).

CONCLUSIONS

Compared to induction of labor at ≥39 weeks, early term induction of labor was not associated with an increased risk of CD in nulliparous women with gestational hypertension.

Induction of labour for postdates in nulliparous women with uncomplicated pregnancy - is the caesarean section rate really lower?

Induction for "post-dates" is a very common procedure and in Queensland, Australia, accounts for 35.5% of all inductions. Systematic reviews all conclude that induction of labour does not increase the risk of caesarean section (CS). However, these reviews have generally included a mixed population and have not stratified for parity. We report in a retrospective cohort study involving only nulliparous women with uncomplicated singleton pregnancy at 40° to 41⁶ weeks that compared to spontaneous labour, incidence of CS was significantly higher in the induction group, 22.2% versus 12.1% (OR 2.06; 95% CI 1.93-2.20) at 40° to 41⁶ weeks versus spontaneous labour at 40° to 41⁶ weeks; and also higher at 21.0% versus 14.9% (OR 1.52; 95% CI 1.34-1.73) at 40° to 40⁶ weeks versus spontaneous labour at 41° to 41⁶ weeks (expectant management).

Elective Induction of Labor Compared With Expectant Management of Nulliparous Women at 39 Weeks of Gestation: A Randomized Controlled Trial

OBJECTIVE

To evaluate whether the elective induction of labor in nulliparous women with an unfavorable cervix affects the cesarean delivery rate.

METHODS

We conducted a randomized controlled trial at a tertiary care medical center. Nulliparous woman between 38 0/7 and 38 6/7 weeks of gestation who were least 18 years of age with a singleton gestation and a Bishop score of 5 or less were randomized to elective induction of labor or expectant management. The induction of labor group was induced within 1 week of enrollment but not before 39 0/7 weeks of gestation. The control group continued routine prenatal care with admission for labor or obstetric indication. The primary outcome was cesarean delivery. Assuming a 20% rate in women in a control group, 80% power, and a goal to detect a twofold increase to 40% in the induction of labor group, 162 patients were needed.

RESULTS

From March 2010 to February 2014, 82 patients were randomly allocated to induction of labor and 80 to expectant management. Baseline characteristics were similar between groups. The cesarean delivery rate in the induction of labor group was 30.5% (25/82) compared with 17.7% (14/79) in the expectant management group (relative risk 1.72, 95% confidence interval 0.96-3.06).

CONCLUSION

In nulliparous women with a Bishop score of 5 or less, elective induction after 39 0/7 weeks of gestation compared with expectant management of pregnancy did not double the rate of cesarean delivery.

CLINICAL TRIAL REGISTRACTION

ClinicalTrials.gov, www.clinicaltrials.gov, NCT01076062.

LEVEL OF EVIDENCE

I.

Elective induction of labour and maternal request: a national population-based study

OBJECTIVE

To estimate the rate of elective inductions in France and the proportion of them that were maternally requested, and to study the factors associated with elective inductions that were or were not requested by women.

DESIGN

Cross-sectional population-based study.

SETTING

All maternity units in France.

POPULATION

About 14 681 women from the 2010 French National Perinatal Survey of a representative sample of births.

METHODS

Inductions were classified as elective based on their indications and maternal and fetal characteristics, collected from medical records. Elective inductions requested by women were identified from the mother's postpartum interviews. Polytomous logistic regression analysis was used to study the determinants of inductions that were or were not maternally requested. Women with spontaneous labour served as the comparison group.

MAIN OUTCOME MEASURE

Rate of elective inductions.

RESULTS

The induction rate was 22.6, 13.9% elective. Among elective inductions, 47.3% were requested by women. The characteristics of mothers, pregnancies, and maternity units were similar in both groups of elective inductions. The main associated factors were parity 2 or more [adjusted odds ratio (OR) 4.7, 95% confidence interval (CI) 3.1-7.2 for maternally requested inductions and aOR of 1.8 (95% CI1.2-2.7) for unrequested inductions, compared with parity 0] and private hospital status [aOR 4.5 95% (CI 3.3-6.0) for maternally requested inductions and aOR 3.7 (95% CI 2.8-4.9) for inductions not requested by the mother]. We found no association between maternal social characteristics and type of elective induction.

CONCLUSION

Parity and organisational factors appear to influence the decision about elective inductions. It would be interesting to determine how obstetricians and women make this decision and for what reasons.

TWEETABLE ABSTRACT

About 13.9% of inductions of labour were elective in France, 47.3% of these requested by women.

Measures of success: Prediction of successful labor induction

Ideally, all pregnant women would enter labor spontaneously at the safest time to yield the best health outcomes for both themselves and their newborns. Unfortunately, this does not always happen and leaves obstetric providers weighing the maternal and fetal risks of continued expectant management versus labor induction. Several elements have been reported to affect the success rate of an induction, including the Bishop score, maternal parity, body mass index (BMI), age, medical comorbidities, fetal gestational age, and estimated weight, as well as the hospital site and provider practice. Recent data suggest that the decision to induce or continue expectant management in anticipation of labor is an important variable in determining whether a woman has a safe and successful delivery.

Association of Second-Trimester Cervical Length With Prolonged Pregnancy

OBJECTIVE

To estimate whether there is an association between second-trimester cervical length and prolonged pregnancy (defined as delivery at or beyond 41 weeks of gestation).

METHODS

This is a cohort study of nulliparous women with a singleton pregnancy who underwent routine cervical length measurement between 18 and 24 weeks of gestation. Women were divided into quartiles by cervical length and the association with prolonged pregnancy was evaluated in bivariable and multivariable analyses. A planned secondary analysis included only women who achieved at least 39 weeks of gestation.

RESULTS

During the study period, a total of 9,165 women met inclusion criteria, of whom 1,481 (16.2%) had a prolonged pregnancy. Women in increasing cervical length quartiles were more likely to experience a prolonged pregnancy (12.9%, 15.8%, 17.1%, 18.6%, P<.001). This association remained significant when controlling for possible confounding variables. An analysis confined to women who achieved at least 39 weeks of gestation was consistent with the overall analysis.

CONCLUSION

Increasing second-trimester cervical length is associated with an increased likelihood of having a prolonged pregnancy in nulliparous women.

LEVEL OF EVIDENCE

II.

Nonmedically indicated induction vs expectant treatment in term nulliparous women

OBJECTIVE

The purpose of this study was to compare maternal and neonatal outcomes in nulliparous women with nonmedically indicated inductions at term vs those expectantly treated.

STUDY DESIGN

Data were obtained from maternal and neonatal charts for all deliveries on randomly selected days across 25 US hospitals over a 3-year period. A low-risk subset of nulliparous women with vertex nonanomalous singleton gestations who delivered 38 0/7 to 41 6/7 weeks were selected. Maternal and neonatal outcomes for nonmedically indicated induction within each week were compared with women who did not undergo nonmedically indicated induction during that week. Multivariable analysis was used to adjust for hospital, maternal age, race/ethnicity, body mass index, cigarette use, and insurance status.

RESULTS

We found 31,169 women who met our criteria. Neonatal complications were either less frequent with nonmedically indicated induction or no different between groups. Nonmedically indicated induction was associated with less frequent peripartum infections (odds ratio [OR], 0.39; 95% confidence interval [CI], 0.16-0.98) at 38 weeks of gestation and less frequent third- and fourth-degree lacerations (OR, 0.60; 95% CI, 0.42-0.86) and less frequent peripartum infections (OR, 0.66; 95% CI, 0.49-0.90) at 39 weeks of gestation. Nonmedically indicated induction was associated with a longer admission-to-delivery time by approximately 3-4 hours and increased odds of cesarean delivery at 38 (OR, 1.50; 95% CI, 1.08-2.08) and 40 weeks (OR, 1.30; 95% CI, 1.15-1.46) of gestation.

CONCLUSION

At 39 weeks of gestation, nonmedically indicated induction is associated with lower maternal and neonatal morbidity than women who are expectantly treated.

Methods of cervical ripening and labor induction: pharmacologic

Over the years, multiple forms and doses of pharmacologic agents have been used for cervical ripening and labor induction. This chapter will review potential criteria and article situations for choosing a particular pharmacologic agent. The discussion in this chapter will be limited to comparisons between pharmacologic agents; direct comparisons between mechanical agents and pharmacologic agents will largely be reviewed in the accompanying article: Methods of cervical ripening and labor induction: mechanical. For the purposes of this discussion, the term labor induction will be limited to patients with a "favorable cervix" by Bishop's score <6, whereas the term cervical ripening will be limited to patients with an unfavorable cervix and includes subsequent induction or augmentation of labor. Although the pharmacologic agent used for the initial cervical ripening process is the focus of this discussion, subsequent treatment with oxytocin may or may not be required for delivery.

Maternal and neonatal outcomes in electively induced low-risk term pregnancies

OBJECTIVE

Elective induction of labor has been discouraged over concerns regarding increased complications. We evaluated the mode of delivery and maternal and neonatal morbidities in low-risk patients whose labor was electively induced or expectantly managed at term.

STUDY DESIGN

This was a retrospective cross-sectional study from 12 US institutions (19 hospitals), 2002 through 2008 (Safe Labor Consortium). Healthy women with viable, vertex singleton pregnancies at 37-41 weeks of gestation were included. Women electively induced in each week were compared with women managed expectantly. The primary outcome was mode of delivery.

RESULTS

Of 131,243 low-risk deliveries, 13,242 (10.1%) were electively induced. The risk of cesarean delivery was lower at each week of gestation with elective induction vs expectant management regardless of parity and modified Bishop score (for unfavorable nulliparous patients at: 37 weeks = 18.6% vs 34.2%, adjusted odds ratio, 0.40; [95% confidence interval, 0.18-0.88]; 38 weeks = 28.4% vs 35.4%, 0.65 [0.49-0.85]; 39 weeks = 23.6% vs 38.5%, 0.47 [0.38-0.57]; 40 weeks = 32.3% vs 42.3%, 0.70 [0.59-0.81]). Maternal infections were significantly lower with elective inductions. Major, minor, and respiratory neonatal morbidity composites were lower with elective inductions at ≥38 weeks (for nulliparous patients at: 38 weeks = adjusted odds ratio, 0.43; [95% confidence interval, 0.26-0.72]; 39 weeks = 0.75 [0.61-0.92]; 40 weeks = 0.65 [0.54-0.80]).

CONCLUSION

Elective induction of labor at term is associated with decreased risks of cesarean delivery and other maternal and neonatal morbidities compared with expectant management regardless of parity or cervical status on admission.

Relation between induced labour indications and neonatal morbidity

PURPOSE

To assess the main neonatal morbidity results in relation to induced labour indications.

METHODS

Historical groups from a total of 3,817 deliveries over a three year period (2009, 2010 and 2011) in "Mancha-Centro" Hospital (Alcázar de San Juan) formed the study group. All programmed and non-avoidable caesarean sections and pregnancies under 35 weeks were excluded. The main variable result was a neonatal morbidity variable made up of the Apgar score after 5 min, pH of umbilical artery <7.10 and the neonatal need for resuscitation type III-V. Multivariate analysis was used to control confounding variables.

RESULTS

The incidence of induced labour was 22.6 % (862). The highest indication was premature rupture of membranes for more than 12 h 22.8 % (190), poorly controlled diabetes 22.6 % (189) and oligoamnios 16.2 % (135). The rate of pH lower than 7.10 was 2.8 % (22), the rate of the Apgar score lower than 7 after 5 min was 0.2 % (2) and the neonatal need for resuscitation type III-IV was 5.7 % (48) for induced labour. The relation between induced labour and neonatal morbidity indicators were not statistically significant. 10.1 % (4) of induced labour for suspected intrauterine growth restriction and 8.6 % (10) of postterm pregnancies required neonatal resuscitation type III-IV.

DISCUSSION

No relation was found between induced labour and the neonatal morbidity indicators. The highest neonatal risk indicator is when a intrauterine growth restriction, hypertensión/preeclampsia or a postterm pregnancy is suspected.

Risk of cesarean in obese nulliparous women with unfavorable cervix: elective induction vs expectant management at term

OBJECTIVE

The objective of the study was to examine maternal and neonatal outcomes in obese nulliparous women with an unfavorable cervix undergoing elective induction of labor compared with expectant management after 39.0 weeks.

STUDY DESIGN

This was a retrospective analysis of a cohort of nulliparous women with a vertex singleton gestation who delivered at MedStar Washington Hospital Center from 2007 to 2012. Patients with unfavorable cervix between 38.0 and 38.9 weeks (modified Bishop <5) and a body mass index of 30.0 kg/m(2) or greater at the time of delivery were included. Women undergoing elective induction between 39.0 and 40.9 weeks' gestation were compared with those who were expectantly managed beyond 39.0 weeks. Outcomes were analyzed using χ(2), Student t, or Wilcoxon rank sum tests as appropriate with a significance set at P < .05.

RESULTS

Sixty patients meeting inclusion criteria underwent elective induction of labor and were compared with 410 patients expectantly managed beyond 39.0 weeks. The rate of cesarean delivery was significantly higher in the electively induced group (40.0% vs 25.9%, respectively, P = .022). Other maternal outcomes, including operative vaginal delivery, rate of third- or fourth-degree lacerations, chorioamnionitis, postpartum hemorrhage, and a need for a blood transfusion were similar. The neonatal intensive care unit admission rate was higher in the electively induced group (18.3% vs 6.3%, P = .001). Birthweight, umbilical artery pH less than 7.0, and Apgar less than 7 at 5 minutes were similar.

CONCLUSION

Elective labor induction at term in obese nulliparous parturients carries an increased risk of cesarean delivery and higher neonatal intensive care unit admission rate as compared with expectant management.

Obstetric care consensus no. 1: safe prevention of the primary cesarean delivery

In 2011, one in three women who gave birth in the United States did so by cesarean delivery. Cesarean birth can be life-saving for the fetus, the mother, or both in certain cases. However, the rapid increase in cesarean birth rates from 1996 to 2011 without clear evidence of concomitant decreases in maternal or neonatal morbidity or mortality raises significant concern that cesarean delivery is overused. Variation in the rates of nulliparous, term, singleton, vertex cesarean births also indicates that clinical practice patterns affect the number of cesarean births performed. The most common indications for primary cesarean delivery include, in order of frequency, labor dystocia, abnormal or indeterminate (formerly, nonreassuring) fetal heart rate tracing, fetal malpresentation, multiple gestation, and suspected fetal macrosomia. Safe reduction of the rate of primary cesarean deliveries will require different approaches for each of these, as well as other, indications. For example, it may be necessary to revisit the definition of labor dystocia because recent data show that contemporary labor progresses at a rate substantially slower than what was historically taught. Additionally, improved and standardized fetal heart rate interpretation and management may have an effect. Increasing women's access to nonmedical interventions during labor, such as continuous labor and delivery support, also has been shown to reduce cesarean birth rates. External cephalic version for breech presentation and a trial of labor for women with twin gestations when the first twin is in cephalic presentation are other of several examples of interventions that can contribute to the safe lowering of the primary cesarean delivery rate.

Safe prevention of the primary cesarean delivery

In 2011, 1 in 3 women who gave birth in the United States did so by cesarean delivery. Cesarean birth can be lifesaving for the fetus, the mother, or both in certain cases. However, the rapid increase in cesarean birth rates from 1996 through 2011 without clear evidence of concomitant decreases in maternal or neonatal morbidity or mortality raises significant concern that cesarean delivery is overused. Variation in the rates of nulliparous, term, singleton, vertex cesarean births also indicates that clinical practice patterns affect the number of cesarean births performed. The most common indications for primary cesarean delivery include, in order of frequency, labor dystocia, abnormal or indeterminate (formerly, nonreassuring) fetal heart rate tracing, fetal malpresentation, multiple gestation, and suspected fetal macrosomia. Safe reduction of the rate of primary cesarean deliveries will require different approaches for each of these, as well as other, indications. For example, it may be necessary to revisit the definition of labor dystocia because recent data show that contemporary labor progresses at a rate substantially slower than what was historically taught. Additionally, improved and standardized fetal heart rate interpretation and management may have an effect. Increasing women's access to nonmedical interventions during labor, such as continuous labor and delivery support, also has been shown to reduce cesarean birth rates. External cephalic version for breech presentation and a trial of labor for women with twin gestations when the first twin is in cephalic presentation are other of several examples of interventions that can contribute to the safe lowering of the primary cesarean delivery rate.

Timing of delivery in women with diabetes in pregnancy

The incidence of both gestational and pre-gestational diabetes is increasing worldwide. The main cause of this increase is likely the concomitant increase in the incidence of global obesity, but in the case of gestational diabetes, changes in the diagnostic criteria are also a contributing factor. The adverse outcomes associated with pre-gestational diabetes are well known and have led clinicians to implement various strategies that include increased fetal surveillance and induction of labour at various gestational ages. In many cases these same strategies have been applied in clinical practice also to women with gestational diabetes despite there being differences in the type and magnitude of perinatal complications associated with this diagnosis. Despite the widespread application of these clinical practices, there is a paucity of quality data in the medical literature to guide the clinician in choosing a strategy for fetal surveillance and timing of delivery in both gestational diabetes and pre-gestational diabetes pregnancies. In the following review, we will discuss the rationale and consequences of planned delivery in gestational diabetes and pre-gestational diabetes, the evidence supporting different strategies for delivery and finally highlight future targets for research in this area.

Induction of labour

OBJECTIVE

To review the most current literature in order to provide evidence-based recommendations to obstetrical care providers on induction of labour.

OPTIONS

Intervention in a pregnancy with induction of labour.

OUTCOMES

Appropriate timing and method of induction, appropriate mode of delivery, and optimal maternal and perinatal outcomes.

EVIDENCE

Published literature was retrieved through searches of PubMed, CINAHL, and The Cochrane Library in 2010 using appropriate controlled vocabulary (e.g., labour, induced, labour induction, cervical ripening) and key words (e.g., induce, induction, augmentation). Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies. There were no date or language restrictions. Searches were updated on a regular basis and incorporated in the guideline to the end of 2010. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies.

VALUES

The evidence in this document was rated using criteria described in the Report of the Canadian Task Force on Preventative Health Care (Table 1). SUMMARY STATEMENTS: 1. Prostaglandins E(2) (cervical and vaginal) are effective agents of cervical ripening and induction of labour for an unfavourable cervix. (I) 2. Intravaginal prostaglandins E(2) are preferred to intracervical prostaglandins E(2) because they results in more timely vaginal deliveries. (I).

Association and risk factors between induction of labor and cesarean section

OBJECTIVE

To determine risk factors and to quantify the risk of cesarean section (CS) associated with labor induction.

METHOD

A prospective controlled study of women admitted for labor induction with PGE2 in a single tertiary medical center. Outcome was compared with women who presented with spontaneous onset of delivery.

RESULTS

The induction group were characterized by a higher body mass index (BMI), lower Bishop score and a higher cervical length at presentation compared with controls. Labor induction with PGE2 was associated with increased risk of CS (14.8% versus 4.5%, p = 0.02). This association persists after adjustment for potential confounders including Bishop score at presentation (OR = 2.9, 95% CI 1.03-11.8). The risk of CS was especially high for nulliparous (24.4% versus 5.1%, p = 0.02), overweight (21.2% versus 3.7%, p = 0.047), induction at <40 weeks of gestation (22.2% versus 2.2%, p = 0.004), in Bishop score <4 (18.2% versus 4.5%, p = 0.03), cervical length >25 mm (19.2% versus 4.5%, p = 0.005), or intact membranes (25.0% versus 4.5%, p = 0.02) at presentation.

CONCLUSIONS

Labor induction with PGE2 is associated with increased risk of CS. These data should be taken into consideration when deciding on labor induction, especially in the absence of clear medical indication.

Induction of labor and risk of postpartum hemorrhage in low risk parturients

Objective

Labor induction is an increasingly common procedure, even among women at low risk, although evidence to assess its risks remains sparse. Our objective was to assess the association between induction of labor and postpartum hemorrhage (PPH) in low-risk parturients, globally and according to its indications and methods.

Method

Population-based case-control study of low-risk women who gave birth in 106 French maternity units between December 2004 and November 2006, including 4450 women with PPH, 1125 of them severe, and 1744 controls. Indications for labor induction were standard or non-standard, according to national guidelines. Induction methods were oxytocin or prostaglandins. Multilevel multivariable logistic regression modelling was used to test the independent association between induction and PPH, quantified as odds ratios.

Results

After adjustment for all potential confounders, labor induction was associated with a significantly higher risk of PPH (adjusted odds ratio, AOR1.22, 95%CI 1.04–1.42). This excess risk was found for induction with both oxytocin (AOR 1.52, 95%CI 1.19–1.93 for all and 1.57, 95%CI 1.11–2.20 for severe PPH) and prostaglandins (AOR 1.21, 95%CI 0.97–1.51 for all and 1.42, 95%CI 1.04–1.94 for severe PPH). Standard indicated induction was significantly associated with PPH (AOR1.28, 95%CI 1.06–1.55) while no significant association was found for non-standard indicated inductions.

Conclusion

Even in low risk women, induction of labor, regardless of the method used, is associated with a higher risk of PPH than spontaneous labor. However, there was no excess risk of PPH in women who underwent induction of labor for non-standard indications. This raises the hypothesis that the higher risk of PPH associated with labor induction may be limited to unfavorable obstetrical situations.

Maternal outcome monitoring: induction of labor versus spontaneous onset of labor—a retrospective data analysis

PURPOSE

To determine the efficacy and maternal complication rates of induction of labor, and to identify a concrete point in time for induction with the lowest possible risk for adverse events.

METHODS

We designed a retrospective data analysis of all births at the general hospital of Vienna from 2003 to 2008(n = 16,872) and compared maternal complications of induced labors from 38 or more weeks of gestation versus spontaneous deliveries. The ethical committee of the General Hospital of Vienna and the Medical University of Vienna monitored this study and provided approval.

RESULTS

Women who had induction between 38 and 42 weeks of gestation (n = 1,254) had a significant higher risk for the need of a secondary cesarean (15.2 vs. 8.6%;p\0.001) and a higher chance for abnormally adherent placentas (1.5 vs. 2.5%; p = 0.13). The amount of maternal blood loss was equal in both groups. Concerning the question when to induct labor, there was no significant difference of distribution of complications between induced labors at term and induction within the next 10 days.

CONCLUSIONS

This study suggests that induction is associated with a higher risk for secondary cesareans and abnormally adherent placentas. The exact time of induction seems to be irrelevant between expected date of delivery and the next 10 days.

Induction of labor compared to expectant management in low-risk women and associated perinatal outcomes

OBJECTIVE

We sought to examine the association of labor induction and perinatal outcomes.

STUDY DESIGN

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).

RESULTS

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.

CONCLUSION

Induction of labor in low-risk women at term is not associated with increased risk of cesarean delivery compared to delivery later.

The influence of practice management on primary cesarean birth

As the cesarean delivery rate has increased to once unimaginable levels, obstetricians should question the loss of our credibility. Older mothers, obesity, larger birth weights, too many twins, and no more breech vaginal deliveries have all been cited as contributing factors to the increase in primary cesarean birth, but one cannot neglect the influence of physician practice style. Attempts to curtail or reverse the escalating incidence of primary abdominal deliveries should focus on caution with inductions of labor, patience with the management of arrest disorders, more accurate assessment of fetal compromise, patient education and informed decision making about the benefits/risks of operative delivery, and improvement in the medicolegal environment.

Predictors of induction success

If the prediction of induction success is to be used as a tool to lower the frequency of a first cesarean delivery, such prediction would need to be among women who are undergoing elective induction, and would need to indicate which women are more likely to have cesarean if they are induced as opposed to expectantly managed. This review summarizes the data that link elective labor induction and cesarean delivery, as well as the factors (or lack thereof) that may be used to better understand which women who are induced ultimately have a vaginal delivery.

Factors that influence the practice of elective induction of labor: what does the evidence tell us?

Elective induction of labor has been linked to increased rates of prematurity and rising rates of cesarean birth. The purpose of this investigation was to evaluate current trends in induction of labor scholarship focusing on evidence-based factors that influence the practice of elective induction. A key word search was conducted to identify studies on the practice of elective induction of labor. Analysis of the findings included clustering and identification of recurrent themes among the articles with 3 categories being identified. Under each category, the words/phrases were further clustered until a construct could be named. A total of 49 articles met inclusion criteria: 7 patient, 6 maternity care provider, and 4 organization factors emerged. Only 4 of the articles identified were evidence based. Patient factors were divided into preferences/convenience, communication, fear, pressure/influence, trust, external influences, and technology. Provider factors were then divided into practice preferences/convenience, lack of information, financial incentives, fear, patient desire/demand, and technology. Organization factors were divided into lack of enforcement/accountability, hospital culture, scheduling of staff, and market share issues. Currently, there is limited data-based information focused on factors that influence elective induction of labor. Despite patient and provider convenience/preferences being cited in the literature, the evidence does not support this practice.

Changes in labor patterns over 50 years

OBJECTIVE

The objective of the study was to examine differences in labor patterns in a modern cohort compared with the 1960s in the United States.

STUDY DESIGN

Data from pregnancies at term, in spontaneous labor, with cephalic, singleton fetuses were compared between the Collaborative Perinatal Project (CPP, n = 39,491 delivering 1959-1966) and the Consortium on Safe Labor (CSL; n = 98,359 delivering 2002-2008).

RESULTS

Compared with the CPP, women in the CSL were older (26.8 ± 6.0 vs 24.1 ± 6.0 years), heavier (body mass index 29.9 ± 5.0 vs 26.3 ± 4.1 kg/m(2)), had higher epidural (55% vs 4%) and oxytocin use (31% vs 12%), and cesarean delivery (12% vs 3%). First stage of labor in the CSL was longer by a median of 2.6 hours in nulliparas and 2.0 hours in multiparas, even after adjusting for maternal and pregnancy characteristics, suggesting that the prolonged labor is mostly due to changes in practice patterns.

CONCLUSION

Labor is longer in the modern obstetrical cohort. The benefit of extensive interventions needs further evaluation.

Timing of delivery and pregnancy outcomes among laboring nulliparous women

OBJECTIVE

The objective of the study was to compare pregnancy outcomes by completed week of gestation after 39 weeks with outcomes at 39 weeks.

STUDY DESIGN

Secondary analysis of a multicenter trial of fetal pulse oximetry in spontaneously laboring or induced nulliparous women at a gestation of 36 weeks or longer. Maternal outcomes included a composite (treated uterine atony, blood transfusion, and peripartum infections) and cesarean delivery. Neonatal outcomes included a composite of death, neonatal respiratory and other morbidities, and neonatal intensive care unit admission.

RESULTS

Among the 4086 women studied, the risks of the composite maternal outcome (P value for trend < .001), cesarean delivery (P < .001), and composite neonatal outcome (P = .047) increased with increasing gestational age from 39 to 41 or more completed weeks. Adjusted odds ratios (95% confidence interval) for 40 and 41 or more weeks, respectively, compared with 39 weeks were 1.29 (1.03-1.64) and 2.05 (1.60-2.64) for composite maternal outcome, 1.28 (1.05-1.57) and 1.75 (1.41-2.16) for cesarean delivery, and 1.25 (0.86-1.83) and 1.37 (0.90-2.09) for composite neonatal outcome.

CONCLUSION

Risks of maternal morbidity and cesarean delivery but not neonatal morbidity increased significantly beyond 39 weeks.

Impending macrosomia: will induction of labour modify the risk of caesarean delivery?

OBJECTIVE

To compare the annual incidence rates of caesarean delivery between induction of labour and expectant management in the setting of macrosomia.

DESIGN

This is a retrospective cohort study.

SETTING

Deliveries in the USA in 2003.

POPULATION

Singleton births of macrosomic neonates to low-risk nulliparous women at 39 weeks of gestation and beyond.

METHODS

Women who had induction of labour at 39 weeks of gestation with a neonatal birthweight of 4000 ± 125 g (3875-4125 g) were compared with women who delivered (either induced or spontaneous labour) at 40, 41 or 42 weeks (i.e. expectant management), assuming an intrauterine fetal weight gain of 200 g per additional week of gestation. Similar comparisons were made at 40 and 41 weeks of gestation. Chi-square test and multivariable logistic regression analysis were used for statistical comparison.

MAIN OUTCOME MEASURES

Method of delivery, 5-minute Apgar scores, neonatal injury.

RESULTS

There were 132,112 women meeting the study criteria. In women whose labours were induced at 39 weeks and who delivered a neonate with a birthweight of 4000 ± 125 g, the frequency of caesarean was lower compared with women who delivered at a later gestational age (35.2% versus 40.9%; adjusted OR 1.25, 95% CI 1.17-1.33). This trend was maintained at both 40 weeks (36.1% versus 42.6%; adjusted OR 1.31, 95% CI 1.23-1.40) and 41 weeks (38.9% versus 41.8%; adjusted OR 1.16, 95% CI 1.06-1.28) of gestation.

CONCLUSIONS

In the setting of known birthweight, it appears that induction of labour may reduce the risk of caesarean delivery. Future research should concentrate on clinical and radiological methods to better estimate birthweight to facilitate improved clinical care. These findings deserve examination in a large, prospective, randomised trial.

Postpartum hemorrhage in low risk population

OBJECTIVE

To identify risk factors for postpartum hemorrhage (PPH) in low risk patients.

METHODS

All deliveries between 2001 and 2007 were retrieved. Women with well-established preexisting risk factors for PPH were excluded. Among the remaining women (n=15,198) considered at low risk, various factors were assessed to evaluate their role in PPH.

RESULTS

Rates of PPH increased from 1.03 in 2001 to 2.45% in 2007. Gestational age at delivery, induction of labor with oxytocin, cesarean section and regional analgesia were not associated with PPH. Logistic regression analysis demonstrated that the following factors were significantly associated with PPH: increased birth weight (P<0.001), female gender (P=0.006), duration of membrane rupture (P=0.002), duration of second stage (P<0.001), chorioamnionitis (P=0.02), and use of prostaglandins (P=0.041).

CONCLUSION

Early recognition of the specific factors presented as associated with PPH should prompt early intervention to reduce the PPH and maternal morbidity.