The ARRIVE Trial: Interpretation from an Epidemiologic Perspective

Trends in induction of labour and associated co-morbidities and demographics in Queensland, Australia from 2001 to 2020: a population-based study

BACKGROUND

Amongst women who plan a vaginal birth at term, previous studies have reported that rates of induction of labour are increasing potentially impacting other labour and birth outcomes. Indications for induction of labour (IOL) have changed over time though the influences of parity and demographic factors such as age, ethnicity and regionality are not often considered. The aim of this study was to describe the changes in demographic, co-morbidity, IOL indication and clinical outcomes in women undertaking a planned cephalic vaginal birth at term over a 20 year period.

METHODS

A retrospective population-based study was undertaken using routinely collected anonymised perinatal data from Queensland, Australia from January 2001 to December 2020. We included all singleton term (≥ 37 weeks) planned vaginal births. A total of 836,065 births met the study criteria. Data for pregnancy complications and IOL indications were grouped by ICD-10 codes. Analysis was stratified by parity and presented as frequency and percentages over time and the difference in percentages between two defined years.

RESULTS

Rates of IOL increased by 15.5% (31.6 to 47.1%) in nulliparous and 14.6% (26.2 to 40.8% in multiparous women, most notable from 2015 onwards. Over the same period infants born between 37 and 38 weeks gestation increased by 13.9%. (18.1-32%). Amongst co-morbidities gestational diabetes increased from 3.8 to 12.8% and anaemia from 1.7 to 8.1%. As an indication for IOL prolonged pregnancy decreased from 41.0 to 11.2%. In nulliparous women the percentage of intact perineum decreased from 21.3 to 6.7% while episiotomy increased from 20.2 to 38.8%.

CONCLUSIONS

We conclude that for women planning a vaginal birth not only has the rate of IOL increased substantially over the last two decades there also appears to be considerable interaction between demographic, co-morbidity, IOL indications and clinical outcomes that warrants further large population-based research.

Equality, Diversity and Inclusion characteristics measured or reported in randomised trials of intrapartum interventions: A Scoping Review

Background

Equality, diversity and inclusion (EDI) has gained discursive momentum across multiple arenas, including in maternal health research. As a preliminary exploration for future discussion and development, we undertook a scoping review to identify the types, frequency, and extent of EDI characteristics that were measured and reported in randomised controlled trials (RCTs) of intrapartum interventions specifically.

Methods

Joanna Briggs Institute methodological guidance for scoping reviews guided the conduct of the review. The population were women of any parity and risk category who were enrolled in intrapartum RCTs in any birth setting or geographical location. The concept was measured and reported EDI characteristics. CINAHL, MEDLINE, PsycINFO, EMBASE, and CENTRAL were searched from January 2019 to March 2024. Data were extracted using a pre-designed form. The findings were summarised and narratively reported supported by illustrative tables and graphs.

Results

Two-hundred and forty-seven RCTs from 49 countries were included. Eleven EDI characteristics were measured or reported in at least one RCT, although frequency varied. Religion, for example, featured in three RCTs only, whereas Age featured in 222 RCTs. How the EDI characteristics featured also varied. Race/Ethnicity, for example, was described in 21 different ways in 25 RCTs. Similarly, Education was reported in 62 different ways across 96 RCTs. Ninety RCTs limited inclusion to nulliparous participants only, six RCTs required participants to have a minimum educational level, 127 RCTs had inclusion age cut-offs although 23 different variations of this were noted and 15 RCTs excluded participants on the grounds of disability.

Conclusions

This scoping review highlights EDI characteristic measurement and reporting deficits in intrapartum RCTs. There is a critical need for improvements in designing, conducting, and reporting RCTs to incorporate EDI. By adopting more extensive EDI practices a greater understanding of healthcare treatments and innovations leading to enhanced maternal health equity could be achieved.

Relationships Among Mode of Birth, Onset of Labor, and Bishop Score

OBJECTIVE

To investigate mode of birth in relation to onset of labor and Bishop score.

DESIGN

Retrospective observational cohort design.

SETTING

A 434-bed Magnet redesignated community hospital.

PARTICIPANTS

Nulliparous women, 18 years of age or older, who gave birth at 37 to 41 weeks gestation to live, singleton fetuses in the vertex presentation (N = 701).

METHODS

We conducted a retrospective chart review and used chi-square analysis to measure the associations among mode of birth, onset of labor, and Bishop score. We used logistic regression to test the probability of cesarean birth for women undergoing elective induction of labor.

RESULTS

Most participants (n = 531, 75.7%) gave birth vaginally. Significant findings included the following relationships: spontaneous onset of labor and vaginal birth (χ2 = 22.2, Ø = 0.18, p < .001) and Bishop score of greater than or equal to 8 and vaginal birth (χ2 = 4.9, Ø = .14, p = .028). Induction of labor was a significant predictor in cesarean birth when controlling for age and body mass index (OR = 2.1, 95% confidence interval [1.5, 3.1], p < .001).

CONCLUSION

Reducing elective induction of labor in women with low-risk pregnancies may help lower the risk of cesarean birth. Clinically, Bishop score and mode of birth have a weak association, particularly when induction includes cervical ripening.

Caesarean Section frequency in Nulliparous Women induced at 39 weeks versus conventional management: An open label random allocation study

Objective

To compare frequency of caesarean section in singleton primary-para women induced at 39 week and its comparison with conventional management. The other objective was comparison of perinatal and neonatal outcomes.

Method

Open random allocation study was conducted at Gynae/Obst Department JPMC during period from 1st June 2022 to 30th September 2023. Primiparous women with singleton pregnancy without risk factors with gestational age 38 weeks 0 days to 38 weeks six days attending the anti-natal clinic offered to participate after consent. Non-probability convenience sampling method was used for induction. Randomization was done using random number table into one of the two groups, Group-A in which induction was done at 39 weeks while in Group-B induction was done conventionally. Mean age ±SD, gestational age and delivery time was calculated and compared by Student's t test. Frequency of CS, perinatal and neonatal outcomes was compared by χ2 test.

Results

Eighty-two women were inducted in Group-A and eighty-five in Group-B. The mean delivery time in Group-A was significantly more at 8.12±2.77 hours while in Group-B was 7.0±2.62 hours (p = .005). Frequency of CS between two groups was not statistically significant, it was 5 (6.1%) in Group-A and 2 (2.4%) in Group-B (p = 0.412). No significant difference in frequency of NICU admission was seen, in Group-A 8.54% babies were admitted to NICU while in Group-B 16.47% were admitted to NICU (p = 0.122).

Conclusion

No significant difference was observed in frequencies of CS, Foetal, Neonatal, and Maternal outcomes.

The Association Between Unintended Pregnancy and Perinatal Outcomes in Low-Risk Pregnancies: A Retrospective Registry Study in the Netherlands

INTRODUCTION

People with unintended pregnancies might be at increased risk of adverse perinatal outcomes due to structural factors, distress, or delayed prenatal care. Existing studies addressing this association yielded inconsistent findings. Using contemporary data from a large Dutch midwifery care registry, we investigated the association between unintended pregnancy ending in birth and neonatal outcomes, parental morbidity, and obstetric interventions. We extend previous research by exploring whether delayed initiation of prenatal care mediates these associations.

METHOD

This study used data (N = 9803) from a Dutch nationally representative registry of people with low-risk pregnancies receiving primary midwife-led care in the Netherlands between 2012 and 2020. Using logistic (mediation) regression analyses adjusted for potential confounders we investigated associations between unintended pregnancy and neonatal outcomes (low Apgar score, small for gestational age, and prematurity), parental morbidity (hypertension and gestational diabetes mellitus), and obstetric interventions (induction of labor, pain medication, assisted vaginal birth, and cesarean birth) and whether delayed initiation of prenatal care mediated these associations.

RESULTS

Unintended pregnancies were associated with increased odds of low Apgar scores (odds ratio [OR], 1.68; 95% CI, 1.09 -2.59), preterm birth (OR, 1.27; 95% CI, 1.02-1.58), small for gestational age (OR, 1.19; 95% CI, 1.00-1.41), and induction of labor (OR, 1.14; 95% CI, 1.01-1.28). Conversely, unintended pregnancy was associated with a decreased odds of cesarean birth (OR, 0.83; 95% CI, 0.71-0.97). The timing of prenatal care initiation did not mediate any of these associations.

DISCUSSION

Our findings suggest that people in primary midwifery-led care with unintended pregnancies ending in birth are at increased risk for adverse perinatal health outcomes and that structural factors might underlie this link. Health care professionals and policy makers should attend to their own biases and offer nonjudgmental, tailored preventive preconception care and antenatal care strategies for people with higher vulnerabilities.

Outcomes of Elective Induction of Labor at 39 Weeks from a Statewide Collaborative Quality Initiative

OBJECTIVE

This article evaluates the impact of adopting a practice of elective induction of labor (eIOL) at 39 weeks among nulliparous, term, singleton, vertex (NTSV) pregnancies in a statewide collaborative.

STUDY DESIGN

We used data from a statewide maternity hospital collaborative quality initiative to analyze pregnancies that reached 39 weeks without a medical indication for delivery. We compared patients who underwent an eIOL versus those who experienced expectant management. The eIOL cohort was subsequently compared with a propensity score-matched cohort who were expectantly managed. The primary outcome was cesarean birth rate. Secondary outcomes included time to delivery and maternal and neonatal morbidities. Chi-square test, t-test, logistic regression, and propensity score matching methods were used for analysis.

RESULTS

In 2020, 27,313 NTSV pregnancies were entered into the collaborative's data registry. A total of 1,558 women underwent eIOL and 12,577 were expectantly managed. Women in the eIOL cohort were more likely to be ≥35 years old (12.1 vs. 5.3%, p < 0.001), identify as white non-Hispanic (73.9 vs. 66.8%, p < 0.001), and be privately insured (63.0 vs. 61.3%, p = 0.04). When compared with all expectantly managed women, eIOL was associated with a higher cesarean birth rate (30.1 vs. 23.6%, p < 0.001). When compared with a propensity score-matched cohort, eIOL was not associated with a difference in cesarean birth rate (30.1 vs. 30.7%, p = 0.697). Time from admission to delivery was longer for the eIOL cohort compared with the unmatched (24.7 ± 12.3 vs. 16.3 ± 11.3 hours, p < 0.001) and matched (24.7 ± 12.3 vs. 20.1 ± 12.0 hours, p < 0.001) cohorts. Expectantly managed women were less likely to have a postpartum hemorrhage (8.3 vs. 10.1%, p = 0.02) or operative delivery (9.3 vs. 11.4%, p = 0.029), whereas women who underwent an eIOL were less likely to have a hypertensive disorder of pregnancy (5.5 vs. 9.2%, p < 0.001).

CONCLUSION

eIOL at 39 weeks may not be associated with a reduced NTSV cesarean delivery rate.

KEY POINTS

· Elective IOL at 39 weeks may not be associated with a reduced NTSV cesarean delivery rate.. · The practice of elective induction of labor may not be equitably applied across birthing people.. · Further research is needed to identify best practices to support people undergoing labor induction..

Labor Induction in Women with Isolated Polyhydramnios at Term: A Multicenter Retrospective Cohort Analysis

Background: With the increasing popularity of elective induction after 39 + 0 weeks, the question of whether induction of labor (IOL) is safe in women with isolated polyhydramnios has become more relevant. We aimed to evaluate the pregnancy outcomes associated with IOL among women with and without isolated polyhydramnios. Methods: This was a multicenter retrospective cohort that included women who underwent induction of labor at term. The study compared women who underwent IOL due to isolated polyhydramnios to low-risk women who underwent elective IOL due to gestational age only. The main outcome measure was a composite adverse maternal outcome, while the secondary outcomes included maternal and neonatal adverse pregnancy outcomes. Results: During the study period, 1004 women underwent IOL at term and met inclusion and exclusion criteria; 162 had isolated polyhydramnios, and 842 had a normal amount of amniotic fluid. Women who had isolated polyhydramnios had higher rates of the composite adverse maternal outcome (28.7% vs. 20.4%, p = 0.02), prolonged hospital stay, perineal tear grade 3/4, postpartum hemorrhage, and neonatal hypoglycemia. Multivariate analyses revealed that among women with IOL, polyhydramnios was significantly associated with adverse composite maternal outcome [aOR 1.98 (1.27-3.10), p < 0.01]. Conclusions: IOL in women with isolated polyhydramnios at term was associated with worse perinatal outcomes compared to low-risk women who underwent elective IOL. Our findings suggest that the management of women with polyhydramnios cannot be extrapolated from studies of low-risk populations and that clinical decision-making should take into account the individual patient's risk factors and preferences.

Projecting future prolapse outcomes with induction of labor at 39 weeks: a decision analysis

INTRODUCTION AND HYPOTHESIS

In 2018, the ARRIVE trial (A Randomized Trial of Induction Versus Expectant Management) concluded that routine induction of labor (IOL) at 39 weeks gestation decreases cesarean delivery risk, with slightly lighter birthweight infants. We debated whether routine IOL would improve, worsen, or not change POP risk compared with expectant management (EM).

METHODS

We constructed a decision analysis model with a lifetime horizon where nulliparous women reaching 39 weeks underwent IOL or EM. Subsequent vaginal versus cesarean delivery varied based on prior deliveries for up to four births. Subsequent delivery prior to 39 weeks and distribution of gestational age, birthweight, and delivery mode between 24 and 39 weeks was modeled from national data. We modeled increased POP risk with increasing vaginal parity, forceps delivery, and weight of largest infant delivered vaginally, accounting for differential infant weights in each strategy.

RESULTS

IOL and EM have similar population-wide POP risk (15.9% and 15.7% respectively). Among women with only spontaneous vaginal deliveries that reached 39 weeks or beyond, the prevalence of POP was 20% after one delivery and 29% after four deliveries, with no difference between groups. The cesarean rate was lower with IOL (27.8% versus 29.8%). Sensitivity analysis revealed no meaningful thresholds among the variables, supporting model robustness.

CONCLUSION

While routine induction of labor at 39 weeks results in a meaningfully higher vaginal delivery rate, there was no increase in POP, possibly due to the protective effect of lower birthweight.

Factors associated with spontaneous vaginal birth in nulliparous women: A descriptive systematic review

PROBLEM

Spontaneous vaginal birth (SVB) rates for nulliparous women are declining internationally.

BACKGROUND

There is inadequate understanding of factors affecting this trend overall and limited large-scale responses to improve women's opportunity to birth spontaneously.

AIM

To undertake a descriptive systematic review identifying factors associated with spontaneous vaginal birth at term, in nulliparous women with a singleton pregnancy.

METHODS

Quantitative studies of all designs, of nulliparous women with a singleton pregnancy and cephalic presentation, who experienced a SVB at term were included. Nine databases were searched (inception to October 2022). Two reviewers undertook quality appraisal; Randomised Controlled Trials (RCTs) with high risk of bias (ROB 2.0) and other designs with (QATSDD) scoring ≤ 50% were excluded.

FINDINGS

Data were abstracted from 90 studies (32 RCTs, 39 cohort, 9 cross-sectional, 4 prevalence, 5 case control, 1 quasi-experimental). SVB rates varied (13%-99%). Modifiable factors associated with SVB included addressing fear of childbirth, low impact antenatal exercise, maternal positioning during second-stage labour and midwifery led care. Complexities arising during pregnancy and regional analgesia were shown to decrease SVB and other interventions, such as routine induction of labour were equivocal.

DISCUSSION

Antenatal preparation (low impact exercise, childbirth education, addressing fear of childbirth) may increase SVB, as does midwifery continuity-of-care. Intrapartum strategies to optimise labour progression emerged as promising areas for further research.

CONCLUSION

Declining SVB rates may be improved through multi-factorial approaches inclusive of maternal, fetal and clinical care domains. However, the variability of SVB rates testifies to the complexity of the issue.

Effects of the ARRIVE (A Randomized Trial of Induction Versus Expectant Management) Trial on Elective Induction and Obstetric Outcomes in Term Nulliparous Patients

OBJECTIVE

To evaluate the effect of publication of the ARRIVE (A Randomized Trial of Induction Versus Expectant Management) trial on perinatal outcomes in singleton, term, nulliparous patients.

METHODS

An interrupted time series analysis was performed using clinical data for nulliparous singleton births at 39 weeks of gestation or later at 13 hospitals in the Northwest region of the United States (January 2016-December 2020). A modified Poisson regression was used to model time trends and changes after the ARRIVE trial (August 9, 2018). Outcomes of interest were elective induction, unplanned cesarean births, hypertensive disorders of pregnancy, a composite of perinatal adverse outcomes, and neonatal intensive care unit admissions.

RESULTS

The analysis included 28,256 births (15,208 pre-ARRIVE and 13,048 post-ARRIVE). The rate of elective labor induction was 3.6% during the pre-ARRIVE period (January 2016-July 2018) and 10.8% post-ARRIVE (August 2018-December 2020). In the interrupted time series analysis, elective induction increased by 42% (relative risk [RR] 1.42; 95% CI 1.18-1.71) immediately after the ARRIVE trial publication. Thereafter, the trend was unchanged compared with the pre-ARRIVE period. There was no statistically significant change in cesarean birth (RR 0.96; 95% CI 0.89-1.04) or hypertensive disorders of pregnancy (RR 0.91; 95% CI 0.79-1.06) immediately after the trial, and no change in trend. After the ARRIVE trial, there was no immediate change in adverse perinatal outcomes, but a statistically significant increase in trend of adverse perinatal events (1.03; 95% CI 1.01-1.05) when compared with a declining trend observed in the pre-ARRIVE period.

CONCLUSION

Publication of the ARRIVE trial was associated with an increase in elective induction, and no change in cesarean birth or hypertensive disorders of pregnancy in singleton nulliparous patients giving birth at 39 weeks or later. There was a flattening of the pre-ARRIVE decreasing trend in perinatal adverse events.

Regional practice variation in induction of labor in the Netherlands: Does it matter? A multilevel analysis of the association between induction rates and perinatal and maternal outcomes

BACKGROUND

Practice variation in healthcare is a complex issue. We focused on practice variation in induction of labor between maternity care networks in the Netherlands. These collaborations of hospitals and midwifery practices are jointly responsible for providing high-quality maternity care. We explored the association between induction rates and maternal and perinatal outcomes.

METHODS

In a retrospective population-based cohort study, we included records of 184,422 women who had a singleton, vertex birth of their first child after a gestation of at least 37 weeks in the years 2016-2018. We calculated induction rates for each maternity care network. We divided networks in induction rate categories: lowest (Q1), moderate (Q2-3) and highest quartile (Q4). We explored the association of these categories with unplanned caesarean sections, unfavorable maternal outcomes and adverse perinatal outcomes using descriptive statistics and multilevel logistic regression analysis corrected for population characteristics.

FINDINGS

The induction rate ranged from 14.3% to 41.1% (mean 24.4%, SD 5.3). Women in Q1 had fewer unplanned caesarean sections (Q1: 10.2%, Q2-3: 12.1%; Q4: 12.8%), less unfavorable maternal outcomes (Q1: 33.8%; Q2-3: 35.7%; Q4: 36.3%) and less adverse perinatal outcomes (Q1: 1.0%; Q2-3: 1.1%; Q4: 1.3%). The multilevel analysis showed a lower unplanned caesarean section rate in Q1 in comparison with reference category Q2-3 (OR 0.83; p = .009). The unplanned caesarean section rate in Q4 was similar to the reference category. No significant associations with unfavorable maternal or adverse perinatal outcomes were observed.

CONCLUSION

Practice variation in labor induction is high in Dutch maternity care networks, with limited association with maternal outcomes and no association with perinatal outcomes. Networks with low induction rates had lower unplanned caesarean section rates compared to networks with moderate rates. Further in-depth research is necessary to understand the mechanisms that contribute to practice variation and the observed association with unplanned caesarean sections.

Improving the external validity of Antenatal Late Preterm Steroids trial findings

BACKGROUND

The external validity of randomised trials can be compromised when trial participants differ from real-world populations. In the Antenatal Late Preterm Steroids (ALPS) trial of antenatal corticosteroids at late preterm ages, participants had systematically younger gestational ages than those outside the trial setting. As risk of respiratory morbidity (the primary trial outcome) is higher at younger gestations, absolute benefits of corticosteroids calculated in the trial population may overestimate real-world treatment benefits.

OBJECTIVES

To estimate the real-world absolute risk reduction and number-needed-to-treat (NNT) for antenatal corticosteroids at late preterm ages, accounting for gestational age differences between the ALPS and real-world populations.

METHODS

Individual participant data from the ALPS trial (which recruited 2831 women with imminent preterm birth at 34+0 to 36+5 weeks') was appended to population-based data for 15,741 women admitted for delivery between 34+0 and 36+5 weeks' from British Columbia, Canada, 2000-2013. We used logistic regression to calculate inverse odds of sampling weights for each trial participant and re-estimated treatment effects of corticosteroids on neonatal respiratory morbidity in ALPS participants, weighted to reflect the gestational age distribution of the population-based (real-world) sample.

RESULTS

The real-world absolute risk reduction was estimated to be -2.2 (95% CI -4.6, 0.0) cases of respiratory morbidity per 100, compared with -2.8 (95% CI -5.3, -0.3) in original trial data. Corresponding NNTs were 46 in the real-world setting vs 35 in the trial. Our focus on absolute measures also highlighted that the benefits of antenatal corticosteroids may be meaningfully greater at 34 weeks vs. 36 weeks (e.g., risk reductions of -3.7 vs. -1.2 per 100 respectively).

CONCLUSIONS

The absolute risk reductions and NNTs associated with antenatal corticosteroid administration at late preterm ages estimated in our study may be more appropriate for patient counselling as they better reflect the anticipated benefits of treatment when used in a real-world situation.

Factors associated with cesarean birth in nulliparous women: A multicenter prospective cohort study

BACKGROUND

There is widespread concern around the rising rates of cesarean births (CBs), especially among first-time mothers, despite evidence suggesting increased morbidities after birth by cesarean. There are uncertainties around factors associated with rising rates of CBs among first-time mothers in Ireland, and insight into these is essential for understanding the rising trend in CBs. Therefore, this study aimed to identify the factors associated with CBs in nulliparous women.

METHODS

A prospective cohort study was conducted in three maternity hospitals in the Republic of Ireland between 2012 and 2017. Data were collected from 3047 nulliparous women using self-administered surveys antenatally and at 3 months postpartum and from consenting women's hospital records (n = 2755) and analyzed using the Poisson regression to assess associations between demographic and clinical factors and the main outcome measures, planned and unplanned CBs.

RESULTS

Common risk factors for planned and unplanned CBs were being aged ≥40 years, being in private care, multiple pregnancy, and fetus in breech or other malpresentations. An unplanned CB occurred for 22.43% (n = 377/1681) of women who did not have induction of labor (IOL) or who had IOL with no epidural, but the risk was about twice as high for women who had IOL and epidural.

CONCLUSIONS

Findings confirm multifactorial reasons for CB and the challenge of reversing the increasing CB rate if maternal age, overweight/obesity, infertility treatment, multiple pregnancy, and preexisting hypertension in Ireland continue to increase. There is a need to address prelabor interventions, especially IOL combined with epidural analgesia with respect to unplanned CB.

Racial and Ethnic Inequities in Cesarean Birth and Maternal Morbidity in a Low-Risk, Nulliparous Cohort

OBJECTIVE

To evaluate race and ethnicity differences in cesarean birth and maternal morbidity in low-risk nulliparous people at term.

METHODS

We conducted a secondary analysis of a randomized trial of expectant management compared with induction of labor in low-risk nulliparous people at term. The primary outcome was cesarean birth. Secondary outcome was maternal morbidity, defined as: transfusion of 4 or more units of red blood cells, any transfusion of other products, postpartum infection, intensive care unit admission, hysterectomy, venous thromboembolism, or maternal death. Multivariable modified Poisson regression was used to evaluate associations between race and ethnicity, cesarean birth, and maternal morbidity. Indication for cesarean birth was assessed using multivariable multinomial logistic regression. A mediation model was used to estimate the portion of maternal morbidity attributable to cesarean birth by race and ethnicity.

RESULTS

Of 5,759 included participants, 1,158 (20.1%) underwent cesarean birth; 1,404 (24.3%) identified as non-Hispanic Black, 1,670 (29.0%) as Hispanic, and 2,685 (46.6%) as non-Hispanic White. Adjusted models showed increased relative risk of cesarean birth among non-Hispanic Black (adjusted relative risk [aRR] 1.21, 95% CI 1.03-1.42) and Hispanic (aRR 1.26, 95% CI 1.08-1.46) people compared with non-Hispanic White people. Maternal morbidity affected 132 (2.3%) individuals, and was increased among non-Hispanic Black (aRR 2.05, 95% CI 1.21-3.47) and Hispanic (aRR 1.92, 95% CI 1.17-3.14) people compared with non-Hispanic White people. Cesarean birth accounted for an estimated 15.8% (95% CI 2.1-48.7%) and 16.5% (95% CI 4.0-44.0%) of excess maternal morbidity among non-Hispanic Black and Hispanic people, respectively.

CONCLUSION

Non-Hispanic Black and Hispanic nulliparous people who are low-risk at term undergo cesarean birth more frequently than low-risk non-Hispanic White nulliparous people. This difference accounts for a modest portion of excess maternal morbidity.

Term Labor Induction and Cesarean Delivery Risk among Obese Women with and without Comorbidities

OBJECTIVE

Findings of the recent ARRIVE (A Randomized Trial of Induction Versus Expectant Management) trial, showing reduced cesarean risk with elective labor induction among low-risk nulliparous women at 39 weeks' gestation, have the potential to change interventional delivery practices but require examination in wider populations. The aim of this study was to identify whether term induction of labor was associated with reduced cesarean delivery risk among women with obesity, evaluating several maternal characteristics associated with obesity, induction, and cesarean risk.

STUDY DESIGN

We studied administrative records for 66,280 singleton, term births to women with a body mass index ≥30, without a prior cesarean delivery, in New York City from 2008 to 2013. We examined elective inductions in 39 and 40 weeks' gestation and calculated adjusted risk ratios for cesarean delivery risk, stratified by parity and maternal age. We additionally evaluated medically indicated inductions at 37 to 40 weeks among women with obesity and diabetic or hypertensive disorders, comorbidities that are strongly associated with obesity.

RESULTS

Elective induction of labor was associated with a 25% (95% confidence interval: 19-30%) lower adjusted risk of cesarean delivery as compared with expectant management at 39 weeks of gestation and no change in risk at 40 weeks. Patterns were similar when stratified by parity and maternal age. Risk reductions in week 39 were largest among women with a prior vaginal delivery. Women with comorbidities had reduced cesarean risk with early term induction and in 39 weeks.

CONCLUSION

Labor induction at 39 weeks was consistently associated with reduced risk of cesarean delivery among women with obesity regardless of parity, age, or comorbidity status. Cesarean delivery findings from induction trials at 39 weeks among low-risk nulliparous women may generalize more broadly across the U.S. obstetric population, with potentially larger benefit among women with a prior vaginal delivery.

KEY POINTS

· We found reduced cesarean risk with induction at 39 weeks.. · Results were consistent for age and comorbidity subgroups.. · Risk reductions were largest among multiparous women..

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.

Integrative Review of Disparities in Mode of Birth and Related Complications among Mexican American Women

INTRODUCTION

Cesarean rates are particularly high among Hispanic women in some regions of the United States, placing a disproportionate health burden on women and their newborns. This integrative review synthesized the literature on mode of birth (vaginal vs cesarean) and related childbirth complications (hemorrhage, surgical site infection, perineal trauma) among Mexican American women living in the United States.

METHODS

Four electronic databases, PubMed, Embase, CINAHL, and SCOPUS, were searched to identify studies meeting the inclusion criteria, research studies that included Mexican American women who were pregnant or postpartum. Results were limited to English language and publications that were peer-reviewed and published before May 2020. Covidence was used in article identification, screening, and assessment. Critical appraisal of the research was performed using the Quality Assessment Tool for Studies with Diverse Designs.

RESULTS

Ten articles met inclusion criteria. In some studies, Mexican American women born in the United States were more likely to have cesareans than women born in Mexico; in other studies, these findings were reversed. Mexican American women often had lower unadjusted cesarean rates compared with non-Hispanic white women, but adjusting for birth facility (some facilities perform more cesareans than others), sociodemographic, and risk factors often revealed Mexican American women have a higher adjusted risk for cesarean birth. Women with higher socioeconomic status had higher cesarean rates compared with women with lower socioeconomic status. In studies of birth outcome by level of acculturation, women who were US-oriented had higher rates of cesarean and more frequent perinatal complications. By ethnic subgroup, rates of cesarean and complications varied among Hispanic women.

DISCUSSION

Birth facility was associated with perinatal outcomes for Mexican American women; those who gave birth at higher-performing facilities had better outcomes when compared with women who gave birth at lower-performing facilities. After adjusting for pregnancy complications, Mexican American women had a greater risk for cesarean birth compared with non-Hispanic white women, a finding that may have clinical practice implications. Level of acculturation affected birth outcomes, but more research using precise instruments is needed.

Reducing the cesarean delivery rate

BACKGROUND

The cesarean delivery rate has been rising in recent years, having associated maternal morbidities. Elective induction of labor has also been seen to rise during this same time period.

OBJECTIVE

This current study investigated the difference in the cesarean delivery rate between induction of labor and spontaneous labor among nulliparous, term, singleton, and vertex-presenting women.

STUDY DESIGN

A retrospective cohort in a single institution over a seven-year period was used for this analysis, observing the difference in cesarean delivery rate at different term gestational ages and neonatal morbidity using the 5-minute Apgar score < 5.

RESULTS

A statistically significant difference was found in cesarean delivery rate between those women whose labor was induced and those whose labor began spontaneously, at each term gestational age of labor initiation (P < 0.001). The proportion of indications for induction was described (i.e. elective vs. medically-indicated), and no difference was found for neonatal morbidity between the groups analyzed, using the 5-minute Apgar score as the perinatal outcome measure.

CONCLUSION

A comparison was made between spontaneous and induced labor regarding the resultant cesarean delivery rate, and a significant difference was found favoring spontaneous labor. This should be considered when electing to deliver using an induction methodology for nulliparous women, especially when there are no medical indications for it.

Maternal and Perinatal Outcomes of Expectant Management of Full-Term, Low-Risk, Nulliparous Patients

OBJECTIVE

To compare risks of maternal and perinatal outcomes by completed week of gestation from 39 weeks in low-risk nulliparous patients undergoing expectant management.

METHODS

We conducted a secondary analysis of a multicenter randomized trial of elective induction of labor at 39 weeks of gestation compared with expectant management in low-risk nulliparous patients. Participants with nonanomalous neonates, who were randomized to and underwent expectant management and attained 39 0/7 weeks of gestation, were included. Delivery gestation was categorized by completed week: 39 0/7-39 6/7 (39 weeks), 40 0/7-40 6/7 (40 weeks), and 41 0/7-42 2/7 (41-42 weeks) (none delivered after 42 2/7). The coprimary outcomes were cesarean delivery and a perinatal composite (death, respiratory support, 5-minute Apgar score 3 or less, hypoxic ischemic encephalopathy, seizure, sepsis, meconium aspiration syndrome, birth trauma, intracranial or subgaleal hemorrhage, or hypotension requiring vasopressor support). Other outcomes included a maternal composite (blood transfusion, surgical intervention for postpartum hemorrhage, or intensive care unit admission), hypertensive disorders of pregnancy, peripartum infection, and neonatal intermediate or intensive care unit admission. For multivariable analysis, P<.0125 was considered to indicate statistical significance for the coprimary outcomes.

RESULTS

Of 2,502 participants who underwent expectant management, 964 (38.5%) delivered at 39 weeks of gestation, 1,111 (44.4%) at 40 weeks, and 427 (17.1%) at 41-42 weeks. The prevalence of medically indicated delivery was 37.9% overall and increased from 23.8% at 39 weeks of gestation to 80.3% at 41-42 weeks. The frequency of cesarean delivery (17.3%, 22.0%, 37.5%; P<.001) and the perinatal composite (5.1%, 5.9%, 8.2%; P=.03) increased with 39, 40, and 41-42 weeks of gestation, respectively, and hypertensive disorders of pregnancy decreased (16.4%, 12.1%, 10.8%, P=.001). The adjusted relative risk, 95% CI (39 weeks as referent) was significant for cesarean delivery at 41-42 weeks of gestation (1.93, 1.61-2.32) and for hypertensive disorders of pregnancy at 40 weeks (0.71, 0.58-0.88) and 41-42 weeks (0.61, 0.45-0.82). None of the other outcomes were significant.

CONCLUSION

In expectantly managed low-risk nulliparous participants, the frequency of medically indicated induction of labor, and the risks of cesarean delivery but not the perinatal composite outcome, increased significantly from 39 to 42 weeks of gestation.

An hypothetical external validation of the ARRIVE trial in a European academic hospital

BACKGROUND

Recent evidence supports elective induction of labor at 39 weeks in low-risk pregnancies to improve maternal and perinatal outcomes. This evidence includes the ARRIVE trial (A Randomized Trial of Induction Versus Expectant Management). However, concerns have been raised on the external validity of the ARRIVE trial, especially with regard to the demographic and clinical characteristics of the pregnant women recruited.

OBJECTIVE

This study compared the outcomes in a cohort of consecutive pregnant women, who fulfilled the criteria of the ARRIVE trial and were managed expectantly in an Italian referral academic hospital, with those reported in the expectant and induction arms of the ARRIVE trial.

STUDY DESIGN

This was a retrospective single-center study. Consecutive low-risk nulliparous women who fulfilled the ARRIVE trial criteria were evaluated for eligibility at 36-38 weeks of gestation. Those who neither developed complications nor delivered spontaneously before 39 weeks were eligible for this comparative analysis. Maternal and fetal growth and wellbeing were screened and monitored from 36 to 38 weeks of gestation.

RESULTS

A total of 1696 patients met the established criteria at recruitment. Of these, 343 spontaneously delivered in <39 weeks, 82 delivered because of maternal indication, and 37 for fetal indication. A total of 1234 pregnant women were eligible for comparison with the elective induction and the expectant management groups of the ARRIVE trial. The socioeconomic status was significantly better, maternal age was significantly higher, and body mass index was significantly lower in our cohort. Cesarean section rate in our cohort was lower than that of the expectant group of the ARRIVE trial (18.7 vs. 22.2%; p = 0.02) and similar to that of the elective induction group (18.7 vs. 18.6%). A new diagnosis of hypertensive disorders during expectant management was noted in 1.6% in our cohort vs. 14.1% in the ARRIVE arm. Among the different obstetric outcomes, only the prevalence of postpartum hemorrhage was not significantly lower in our cohort. The primary perinatal composite outcome was significantly better in our cohort than in both arms of the ARRIVE trial (2.1 vs. 5.4% in the expectant group and 4.3% in the induction group). We did not record cases with an Apgar score ≤ 3 or hypoxic-ischemic encephalopathy.

CONCLUSION

In our cohort, expectant management in low-risk pregnancies with late preterm screening of feto-maternal well-being seemed to achieve better maternal and perinatal outcomes than a universal policy of induction at 39 weeks. The results of the ARRIVE trial should be carefully evaluated in different demographic and clinical settings and cannot be extended to the general population.

A survey of obstetricians' attitudes to induction of labour at 39 weeks gestation with the intention of reducing caesarean section rates

BACKGROUND

Induction of labour (IOL) and caesarean section (CS) rates continue to increase in Australia, New Zealand and globally. There is evidence that CS rates are decreased in the context of medically indicated and elective IOL; therefore, the emerging concept of using IOL as means of preventing CS warrants investigation.

AIMS

To assess obstetricians' opinions of elective IOL at 39 weeks gestation, its feasibility, generalisability and utility as a means of preventing CS in Australia and New Zealand.

MATERIALS AND METHODS

A de-identified cross-sectional survey was distributed electronically to all Fellows and trainees of The Royal Australian and New Zealand College of Obstetricians and Gynaecologists (RANZCOG). The survey was voluntary and distributed with the approval of the RANZCOG Continuing Education Committee. The survey addressed opinions relating to rates of and indications for IOL, the perceived validity of those indications and explored the acceptability of using a screening tool to predict women at increased risk of intra-partum CS and tailoring obstetric management to include the option of IOL at 39 weeks gestation.

RESULTS

The overall response rate was 34% (492/1423) (including trainees) and the response rate was 53% (394/750) for currently practising obstetricians. The majority (90%) of responders agreed on medical and clinical indications for IOL. There was no consensus on the validity of IOL if a woman were at apparent high risk of intra-partum CS; however, 81% (360/443) of clinicians would be interested in a tool that could predict those women at risk.

CONCLUSIONS

There is heterogeneity of obstetrician's beliefs on using IOL at 39 weeks as a mechanism to reduce the CS rate.

Factors Associated with Unplanned Primary Cesarean Birth: Secondary Analysis of the Listening to Mothers in California Survey

BACKGROUND

In many countries, cesarean section has become the most common major surgical procedure. Most nations have high cesarean birth rates, suggesting overuse. Due to the excess harm and expense associated with unneeded cesareans, many health systems are seeking approaches to safe reduction of cesarean rates. Surveys of childbearing women are a distinctive and underutilized source of data for examining factors that may contribute to cesarean reduction.

METHODS

To identify factors associated with unplanned primary cesarean birth, we carried out a secondary analysis of the Listening to Mothers in California Survey, limited to the subgroup who had not had a previous cesarean birth and did not have a planned primary cesarean (n = 1,964). Participants were identified through birth certificate sampling and contacted initially by mail and then by telephone, text message and email, as available. Sampled women could participate in English or Spanish, on any device or with a telephone interviewer. Following bivariate demographic, knowledge and attitude, and labor management analyses, we carried out multivariable analyses to adjust with covariates and identify factors associated with unplanned primary cesarean birth.

RESULTS

Whereas knowledge, attitudes, preferences and behaviors of the survey participants were not associated with having an unplanned primary cesarean birth, their experience of pressure from a health professional to have a cesarean and a series of labor management practices were strongly associated with how they gave birth. These practices included attempted induction of labor, early hospital admission, and labor augmentation. Women's reports of pressure from a health professional to have a primary cesarean were strongly related to the likelihood of cesarean birth.

CONCLUSIONS

While women largely wish to avoid unneeded childbirth interventions, their knowledge, preferences and care arrangement practices did not appear to impact their likelihood of an unplanned primary cesarean birth. By contrast, a series of labor management practices and perceived health professional pressure to have a cesarean were associated with unplanned primary cesarean birth. Improving ways to engage childbearing women and implementing changes in labor management and communication practices may be needed to reduce unwarranted cesarean birth.