Continuation versus discontinuation of oxytocin infusion during the active phase of labour: a randomised controlled trial

Impact of combined propranolol and oxytocin on the process and outcomes of labor: a meta-analysis of randomized controlled trials

PURPOSE

To systematically review the impact of propranolol combined with oxytocin on the process and outcomes of labor.

METHODS

A comprehensive literature search was performed across multiple databases, including China National Knowledge Infrastructure (CNKI), VIP, Wanfang, China Biomedical Literature Database, PubMed, Embase, and the Cochrane Library. All publicly published randomized controlled trials (RCTs) of propranolol combined with oxytocin compared to the use of oxytocin alone in labor were collected. After screening the literature and extracting data, the Cochrane Handbook for Systematic Reviews of Interventions 5.1.0 recommended bias risk assessment tool was used to assess the quality of the included studies. A meta-analysis was conducted using RevMan 5.3 software, and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system was used to rate the quality of evidence for outcome measures.

RESULTS

Meta-analysis results showed that the group receiving propranolol combined with oxytocin was more capable of reducing the cesarean section rate (eight studies, 815 women, RR = 0.67, 95% CI (0.53, 0.86), P = 0.001) and shortening the duration of the latent phase (two studies, 206 women, MD =  - 1.20, 95% CI (- 1.97, - 0.43), P = 0.002) and the duration of the active phase on day 1 (two studies, 296 women, MD =  - 0.69, 95% CI (- 0.83, - 0.54), P < 0.00001), compared to the oxytocin monotherapy group. No significant difference was found between the two groups in terms of the 5-min Apgar score (five studies, 609 women, MD =  - 0.05, 95% CI (- 0.14, 0.04), P = 0.32) and the rate of admissions to the Neonatal Intensive Care Unit (NICU) (three studies, 359 women, RR = 0.82, 95% CI (0.38, 1.79), P = 0.62).

CONCLUSION

The combined use of propranolol and oxytocin can significantly reduce the cesarean section rate, shorten the duration of the latent phase and the duration of the active phase on day 1, and is safe. However, due to the limitations, the conclusions of this article still need to be verified by large-sample, multicenter, rigorously designed high-quality clinical RCTs.

TRIAL REGISTRATION

Registration number is INPLASY202390107.

Discontinuation of Oxytocin in the Second Stage of Labor and its Association with Postpartum Hemorrhage

OBJECTIVE

 The objective of the study was to evaluate whether patients with oxytocin discontinued during the second stage of labor (≥30 minutes prior to delivery) had a lower rate of postpartum hemorrhage (PPH) compared with those with oxytocin continued until delivery or discontinued <30 minutes prior to delivery.

STUDY DESIGN

 Retrospective cohort study was performed from August 1, 2014 to July 31, 2019. Singleton pregnancies of 24 to 42 weeks gestation were included if they reached the second stage of labor and received oxytocin during labor. Patients on anticoagulants were excluded. Patients with oxytocin discontinued ≥30 minutes prior to delivery represented STOPPED and those with oxytocin continued until delivery or discontinued <30 minutes prior to delivery represented CONTINUED. Patient data were abstracted from the electronic medical record. The primary outcome was PPH (≥1,000 mL blood loss). Univariable analyses were performed to compare groups. Multi-variable logistic regression was performed to adjust for prespecified confounders. Planned sub-group analyses by the route of delivery were performed.

RESULTS

 Of 10,421 total patients, 1,288 had oxytocin STOPPED and 9,133 had oxytocin CONTINUED. There were no significant differences in age, race, or ethnicity, body mass index, public insurance, gestational diabetes, or pregnancy-induced hypertension between STOPPED and CONTINUED. The PPH rate was 15.2 and 5.7% in STOPPED and CONTINUED, respectively (p < 0.001). After adjusting for confounders, STOPPED remained at higher odds for PPH (adjusted odds ratio 2.859, 95% confidence interval 2.394, 3.414, p < 0.001). Among cesarean deliveries only, there was no significant difference in the rate of PPH between STOPPED and CONTINUED (38.0 vs. 36.4%, respectively, p = 0.730). However, among vaginal deliveries, the rate of PPH was actually lower in STOPPED than CONTINUED (3.4 vs. 5.2%, respectively, p = 0.024).

CONCLUSION

 The rate of PPH was higher in patients with oxytocin STOPPED compared with CONTINUED. However, among vaginal deliveries, there was a significantly lower rate of PPH in STOPPED. These disparate findings may be explained by the variable impact of second-stage oxytocin on PPH as a function of delivery type.

KEY POINTS

· It is unclear if oxytocin use in the second stage of labor may independently increase the risk of hemorrhage.. · Patients with oxytocin discontinued during the second stage of labor had a higher rate of PPH.. · PPH was significantly lower among vaginal deliveries in patients with oxytocin discontinued..

Outcome of Inducing Labor in Pregnancies with Suspected Fetal Growth Restriction: Oxytocin Discontinuation during the Active Phase of Labor versus Conventional Management

OBJECTIVE

 Although fetal growth restriction (FGR) is associated with an increased risk of cesarean delivery during induced labor, there is limited evidence to guide labor management. This study aimed to investigate the prognosis of induced labor in pregnancies with suspected FGR and whether oxytocin discontinuation during the active phase of labor affects maternal and neonatal outcomes.

STUDY DESIGN

 This retrospective cohort study investigated singleton pregnancies with vertex presentation and indications for labor induction owing to FGR after 34.0 weeks of gestation at Osaka University Hospital. From January 2010 to December 2013, women were conventionally managed, and oxytocin was continued until delivery unless there was an indication for discontinuation (conventional management group). From January 2013 to December 2020, oxytocin was routinely discontinued, or the dose was reduced at the beginning of the active phase of labor (oxytocin discontinuation group).

RESULTS

 A total of 161 women (conventional management group, n = 74; oxytocin discontinuation group, n = 87) were included. After the active phase of induced labor, the total incidence of cesarean delivery was very low (3.1%), and the duration was short (173 ± 145 minutes). Oxytocin discontinuation was associated with lower cesarean delivery (1.1 vs. 5.4%; p = 0.12) and uterine tachysystole (9.8 vs. 23.0%; p = 0.08) rates and longer duration of the second stage of labor (mean: 56.5 ± 90 vs. 34.2 ± 45 minutes; p = 0.08) than conventional management; however, the difference was not significant. The other maternal and neonatal outcomes, including postpartum hemorrhage, did not also significantly differ between them.

CONCLUSION

 After the active phase of induced labor for suspected FGR, the risk of cesarean delivery is low, and the high incidence of uterine tachysystole and rapid labor progression should be considered cautiously. Oxytocin can be safely discontinued during the active phase of labor in women undergoing labor induction for FGR without an increased risk of cesarean delivery or other unfavorable outcomes.

KEY POINTS

· The cesarean delivery rate was low after the active phase.. · The labor progress after the active phase was rapid.. · Oxytocin can be safely discontinued during the active phase..

Impact of discontinuing oxytocin in active labour on neonatal morbidity: an open-label, multicentre, randomised trial

BACKGROUND

Oxytocin is effective in reducing labour duration but can be associated with fetal and maternal complications that could potentially be reduced by discontinuing the treatment during labour. We aimed to assess the impact of discontinuing oxytocin during active labour on neonatal morbidity.

METHODS

STOPOXY was a multicentre, randomised, open-label, controlled, superiority trial conducted in 21 maternity units in France. Participants who received oxytocin before 4 cm dilation were randomly assigned 1:1 to either discontinuous oxytocin (oxytocin infusion stopped beyond a cervical dilation equal to or greater than 6 cm) or continuous oxytocin (administration of oxytocin continued until delivery). Randomisation was stratified by centre and parity. The primary outcome, neonatal morbidity, was assessed at birth using a composite variable defined by an umbilical arterial pH at birth less than 7·10, a base excess greater than 10 mmol/L, umbilical arterial lactates greater than 7 mmol/L, a 5-min Apgar score less than 7, or admission to the neonatal intensive care unit. Efficacy and safety was assessed in participants who were randomly assigned (excluding those who withdrew consent or were deemed ineligible after randomisation) and had reached a cervical dilation of at least 6 cm. This trial is registered with ClinicalTrials.gov, NCT03991091.

FINDINGS

Of 2459 participants randomly assigned between Jan 13, 2020, and Jan 24, 2022, 2170 were eligible to receive the intervention and were included in the final modified intention-to-treat analysis. The primary outcome occurred for 102 (9·6%) of 1067 participants (95% CI 7·9 to 11·5) in the discontinuous oxytocin group and for 101 (9·2%) of 1103 participants (7·6 to 11·0) in the continuous oxytocin group; absolute difference 0·4% (95% CI -2·1 to 2·9); relative risk 1·0 (95% CI 0·8 to 1·4). There were no clinically significant differences in adverse events between the two groups of the safety population.

INTERPRETATION

Among participants receiving oxytocin in early labour, discontinuing oxytocin when the active phase is reached does not clinically or statistically significantly reduce neonatal morbidity compared with continuous oxytocin.

FUNDING

French Ministry of Health and the Département de la Recherche Clinique et du Développement de l'Assistance Publique-Hôpitaux de Paris.

Fetal to Neonatal Heart Rate Transition during Normal Vaginal Deliveries: A Prospective Observational Study

Documentation of fetal to neonatal heart rate (HR) transition is limited. The aim of the current study was to describe HR changes from one hour before to one hour after normal vaginal deliveries. We conducted a prospective observational cohort study in Tanzania from 1 October 2020 to 30 August 2021, including normal vaginal deliveries with normal neonatal outcomes. HR was continuously recorded from one hour before to one hour after delivery, using the Moyo fetal HR meter, NeoBeat newborn HR meter, and the Liveborn Application for data storage. The median, 25th, and 75th HR percentiles were constructed. Overall, 305 deliveries were included. Median (interquartile range; IQR) gestational age was 39 (38-40) weeks and birthweight was 3200 (3000-3500) grams. HR decreased slightly during the last 60 min before delivery from 136 (123,145) to 132 (112,143) beats/minute. After delivery, HR increased within one minute to 168 (143,183) beats/min, before decreasing to around 136 (127,149) beats/min at 60 min after delivery. The drop in HR in the last hour of delivery reflects strong contractions and pushing. The rapid increase in initial neonatal HR reflects an effort to establish spontaneous breathing.

Continued versus discontinued oxytocin after the active phase of labor: An updated systematic review and meta-analysis

Objective

To systematically assess the effect of discontinued vs continued oxytocin after active stage of labour is established.

Methods

Pubmed, Embase, and the Cochrane Library were systematically searched to 18 April 2021. The risk ratio or mean difference with corresponding 95% confidence interval were computed to investigate the effect of intervention or control on maternal and fetus outcomes. This review was registered in the International Prospective Register of Systematic Reviews: CRD42021249635.

Results

Discontinuing oxytocin when the active labour was established might decrease the risk of cesarean delivery [RR (95% CI): 0.84 (0.72–0.98), P = 0.02]. However, when we restricted our analysis to women who performed cesarean section after the active phase was reached, the difference was no longer significant [RR (95% CI): 0.82 (0.60–1.10), P = 0.19]. The incidence of uterine tachysystole [RR (95% CI): 0.36 (0.27–0.49)], postpartum hemorrhage [RR (95% CI): 0.78 (0.65–0.93)], and non-reassuring fetal heart rate [RR (95% CI): 0.66 (0.58–0.76)] were significantly lower in the oxytocin discontinuation group. We also found a possible decrease in the risk of chorioamnionitis in discontinued oxytocin group [RR (95% CI): 2.77 (1.02–5.08)]. An increased duration of active [MD (95% CI): 2.28 (2.86–41.71)] and second [MD (95% CI): 5.36 (3.18–7.54)] phase of labour was observed in discontinued oxytocin group, while the total delivery time was not significantly different [MD (95% CI): 20.17 (-24.92–65.26)].

Conclusion

After the active labor is reached, discontinuation of oxytocin could be considered a new recommendation for the improved maternal and fetal outcomes without delaying labour.

Amniotomy and early oxytocin infusion vs amniotomy and delayed oxytocin infusion for labour augmentation amongst nulliparous women at term: A randomised controlled trial

OBJECTIVE

to compare the effect of amniotomy with early vs delayed oxytocin infusion on successful vaginal delivery.

DESIGN

randomised controlled trial of nulliparous women with spontaneous labour at term.

SETTING

labour suite of a university teaching hospital in Kuala Lumpur, Malaysia.

PARTICIPANTS

240 women were included (120 randomised into two arms).

INTERVENTIONS

the randomisation sequence was generated using a computer randomisation program in two blocks: oxytocin infused early following amniotomy; and oxytocin infused 2 h after amniotomy.

MEASUREMENTS AND FINDINGS

labour duration, mode of delivery, oxytocin dosage used, uterine hyperstimulation, postpartum haemorrhage, Apgar score and admission to the neonatal intensive care unit were recorded. No differences in vaginal delivery rate (62.9% vs 70.9%; p = 0.248) and second-stage labour were found between the early and delayed oxytocin infusion groups (21.2 ± 18.3 min vs 25.5 ± 19.9 min; p = 0.220). The mean interval from amniotomy to vaginal delivery was significantly shorter for the early group (5.8 ± 1.7 h vs 7.0 ± 1.9 h; p = 0.001), and more women in the early group delivered during/before the planned review at 4 h after amniotomy (53.6% vs 10.6%; p<0.001). Maximum oxytocin usage was lower in the early group (5.6 ± 4.4 mL/hour vs 6.8 ± 5.3 mL/hour; p = 0.104).

KEY CONCLUSIONS

early oxytocin augmentation following amniotomy could be employed in low-risk primigravida, given that it is associated with a shorter labour duration without jeopardising maternal or neonatal outcomes.

IMPLICATIONS FOR PRACTICE

low-risk primigravida benefit from early oxytocin infusion following amniotomy, and this can be offered as an additional practice in labour room care.

Is there unwarranted variation in obstetric practice in Australia? Obstetric intervention trends in Queensland hospitals

Objective The aim of this study was to report on the rates of obstetric interventions within each hospital jurisdiction in the state of Queensland, Australia. Methods This project used a whole-of-population linked dataset that included the health and cost data of all mothers who gave birth in Queensland, Australia, between 2012 and 2015 (n=186789), plus their babies (n=189909). Adjusted and unadjusted rates of obstetric interventions and non-instrumental vaginal delivery were reported within each hospital jurisdiction in Queensland. Results High rates of obstetric intervention exist in both the private and public sectors, with higher rates demonstrated in the private than public sector. Within the public sector, there is substantial variation in rates of intervention between hospital and health service jurisdictions after adjusting for confounding variables that influence the need for obstetric intervention. Conclusions Due to the high rates of obstetric interventions statewide, a deeper understanding is needed of what factors may be driving these high rates at the health service level, with a focus on the clinical necessity of the provision of Caesarean sections. What is known about the topic? Variation in clinical practice exists in many health disciplines, including obstetric care. Variation in obstetric practice exists between subpopulation groups and between states and territories in Australia. What does this paper add? What we know from this microlevel analysis of obstetric intervention provision within the Australian population is that the provision of obstetric intervention varies substantially between public sector hospital and health services and that this variation is not wholly attributable to clinical or demographic factors of mothers. What are the implications for practitioners? Individual health service providers need to examine the factors that may be driving high rates of Caesarean sections within their institution, with a focus on the clinical necessity of Caesarean section.

Continued versus discontinued oxytocin stimulation in the active phase of labour (CONDISOX): double blind randomised controlled trial

OBJECTIVE

To determine whether discontinuing oxytocin stimulation in the active phase of induced labour is associated with lower caesarean section rates.

DESIGN

International multicentre, double blind, randomised controlled trial.

SETTING

Nine hospitals in Denmark and one in the Netherlands between 8 April 2016 and 30 June 2020.

PARTICIPANTS

1200 women stimulated with intravenous oxytocin infusion during the latent phase of induced labour.

INTERVENTION

Women were randomly assigned to have their oxytocin stimulation discontinued or continued in the active phase of labour.

MAIN OUTCOME MEASURE

Delivery by caesarean section.

RESULTS

A total of 607 women were assigned to discontinuation and 593 to continuation of the oxytocin infusion. The rates of caesarean section were 16.6% (n=101) in the discontinued group and 14.2% (n=84) in the continued group (relative risk 1.17, 95% confidence interval 0.90 to 1.53). In 94 parous women with no previous caesarean section, the caesarean section rate was 7.5% (11/147) in the discontinued group and 0.6% (1/155)in the continued group (relative risk 11.6, 1.15 to 88.7). Discontinuation was associated with longer duration of labour (median from randomisation to delivery 282 v 201 min; P<0.001), a reduced risk of hyperstimulation (20/546 (3.7%) v 70/541 (12.9%); P<0.001), and a reduced risk of fetal heart rate abnormalities (153/548 (27.9%) v 219/537 (40.8%); P<0.001) but rates of other adverse maternal and neonatal outcomes were similar between groups.

CONCLUSIONS

In a setting where monitoring of the fetal condition and the uterine contractions can be guaranteed, routine discontinuation of oxytocin stimulation may lead to a small increase in caesarean section rate but a significantly reduced risk of uterine hyperstimulation and abnormal fetal heart rate patterns.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02553226.

Cervical Ripening and Labor Induction and Augmentation, 5th Edition

Cervical ripening and induction and augmentation of labor are common procedures in labor and birth units. The potential risks and benefits for the procedure should be explained to women so that they can make informed decisions. Clinicians should be knowledgeable about the methods and medications used and be skilled in maternal-fetal assessment. Adequate nurse staffing is required to monitor the mother and fetus to promote the best possible outcomes. This practice monograph includes information on mechanical and pharmacologic methods for cervical ripening; labor induction and augmentation with oxytocin, a high alert drug; and nurse staffing levels and skills needed to provide safe and effective care during cervical ripening and labor induction and augmentation.

Reducing neonatal morbidity by discontinuing oxytocin during the active phase of first stage of labor: a multicenter randomized controlled trial STOPOXY

BACKGROUND

Oxytocin is effective in reducing labor duration, but can be associated with fetal and maternal complications such as neonatal acidosis and post-partum hemorrhage. When comparing discontinuing oxytocin in the active phase with continuing oxytocin infusion, previous studies were underpowered to show a reduction in neonatal morbidity. Thus, we aim at evaluating the impact of discontinuing oxytocin during the active phase of the first stage of labor on the neonatal morbidity rate.

METHODS

STOPOXY is a multicenter, randomized, open-label, controlled trial conducted in 20 maternity units in France. The first participant was recruited January 17th 2020. The trial includes women with a live term (≥37 weeks) singleton, in cephalic presentation, receiving oxytocin before 4 cm, after an induced or spontaneous labor. Women aged < 18 years, with a lack of social security coverage, a scarred uterus, a multiple pregnancy, a fetal congenital malformation, a growth retardation <3rd percentile or an abnormal fetal heart rate at randomization are excluded. Women are randomized before 6 cm when oxytocin is either continued or discontinued. Randomization is stratified by center and parity. The primary outcome, neonatal morbidity is assessed using a composite variable defined by an umbilical arterial pH at birth < 7.10 and/or a base excess > 10 mmol/L and/or umbilical arterial lactates> 7 mmol/L and/or a 5 min Apgar score < 7 and/or admission in neonatal intensive care unit. The primary outcome will be compared between the two groups using a chi-square test with a p-value of 0.05. Secondary outcomes include neonatal complications, duration of active phase, mode of delivery, fetal and maternal complications during labor and delivery, including cesarean delivery rate and postpartum hemorrhage, and birth experience. We aim at including 2475 women based on a reduction in neonatal morbidity from 8% in the control group to 5% in the experimental group, with a power of 80% and an alpha risk of 5%.

DISCUSSION

Discontinuing oxytocin during the active phase of labor could improve both child health, by reducing moderate to severe neonatal morbidity, and maternal health by reducing cesarean delivery and postpartum hemorrhage rates.

TRIAL REGISTRATION

Clinical trials NCT03991091 , registered June 19th, 2019.

Cervical Ripening and Labor Induction and Augmentation, 5th Edition

Cervical ripening and induction and augmentation of labor are common procedures in labor and birth units. The potential risks and benefits for the procedure should be explained to women so that they can make informed decisions. Clinicians should be knowledgeable about the methods and medications used and be skilled in maternal-fetal assessment. Adequate nurse staffing is required to monitor the mother and fetus to promote the best possible outcomes. This practice monograph includes information on mechanical and pharmacologic methods for cervical ripening; labor induction and augmentation with oxytocin, a high alert drug; and nurse staffing levels and skills needed to provide safe and effective care during cervical ripening and labor induction and augmentation.

Augmentation of labor with oxytocin and its association with delivery outcomes: A large-scale cohort study in 12 public hospitals in Nepal

INTRODUCTION

The use of oxytocin to augment labor is increasing in many low-resource settings; however, little is known about the effects of such use in contexts where resources for intrapartum monitoring are scarce. In this study, we sought to assess the association between augmentation of labor with oxytocin and delivery outcomes.

MATERIAL AND METHODS

We conducted a cohort study in 12 public hospitals in Nepal, including all deliveries with and without augmentation of labor with oxytocin, but excluding elective cesarean sections, women with missing information on augmentation of labor, and women without fetal heart rate on admission. Bivariate and multivariate logistic regression calculating the crude and adjusted risk ratio (aRR) with corresponding 95% CI were performed, comparing (a) intrapartum stillbirth and first-day mortality (primary outcome); and (b) intrapartum monitoring, mode of delivery, postpartum hemorrhage, bag-and-mask ventilation of the newborn, Apgar score, and neonatal death before discharge (secondary outcomes) among women with and without oxytocin-augmented labor.

RESULTS

The total cohort consisted of 78 931 women, of whom 28 915 (37%) had labor augmented with oxytocin and 50 016 (63%) did not have labor augmented with oxytocin. Women with augmentation of labor had no increased risk of intrapartum stillbirth and first-day mortality (aRR 1.24, 95% CI 0.65-2.4), but decreased risks of suboptimal partograph use (aRR 0.71, 95% CI 0.68-0.74), suboptimal fetal heart rate monitoring (aRR 0.50, 95% CI 0.48-0.53), and emergency cesarean section (aRR 0.62, 95% CI 0.59-0.66), and increased risks of bag-and-mask ventilation (aRR 2.1, 95% CI 1.8-2.5), Apgar score <7 at 5 minutes (aRR 1.65, 95% CI 1.49-1.86), and neonatal death (aRR 1.93, 95% CI 1.46-2.56).

CONCLUSIONS

Although augmentation of labor with oxytocin might be associated with beneficial effects, such as improved monitoring and a decreased risk of cesarean section, its use may lead to an increased risk of adverse perinatal outcomes. We urge for a cautious use of oxytocin to augment labor in low-resource contexts, and call for evidence-based guidelines on augmentation of labor in low-resource settings.

CONDISOX- continued versus discontinued oxytocin stimulation of induced labour in a double-blind randomised controlled trial

BACKGROUND

Oxytocin is an effective drug for induction of labour, but is associated with serious adverse effects of which uterine tachysystole, fetal distress and the need of immediate delivery are the most common. Discontinuation of oxytocin once the active phase of labour is established could reduce the adverse effects. The objective is to investigate how the caesarean section rate is affected when oxytocin stimulation is discontinued in the active phase of labour compared to labours where oxytocin is continued.

METHODS

CONDISOX is a double-blind multicentre randomised controlled trial conducted at Danish and Dutch Departments of Obstetrics and Gynaecology. The first participant was recruited on April 8 2016. Based on a clinically relevant relative reduction in caesarean section rate of 7%, an alpha of 0.05, a beta of 80%, we aim for 1200 participating women (600 in each arm). The CONDISOX trial includes women at a gestational age of 37-42 complete weeks of pregnancy, who have uterine activity stimulated with oxytocin infusion for the induction of labour. Women are randomised when the active phase of labour becomes established, to study medication containing either oxytocin (continuous group) or placebo (discontinued group) infusion. Women are stratified by birth site, indication for oxytocin stimulation (induction of labour, prelabour rupture of membranes) and parity (nulliparous, parous +/- previous caesarean section). We will compare the primary outcome, caesarean section rate, in the two groups using a chi-square test with a p-value of 0.05. If superiority is not demonstrated, we have a pre-defined post hoc non-inferiority boundary (margin, delta) at 1.09. Secondary outcomes include duration of the active phase of labour, incidence of uterine tachysystole, postpartum haemorrhage, admission to the neonatal intensive care unit, Apgar score, umbilical arterial blood pH, and birth experience.

DISCUSSION

The high frequency of oxytocin use and the potential risks of both maternal and fetal adverse effects of oxytocin emphasise the need to determine the optimal oxytocin regime for induction of labour.

TRIAL REGISTRATION

NCT02553226 (registered September 17, 2015). Eudra-CT number: 2015-002942-30.

Influence of Body Mass Index on Gestation and Delivery in Nulliparous Women: A Cohort Study

Aims: To assess the influence of obesity on pregnancy and delivery in pregnant nulliparous women. Methods: A cohort, longitudinal, retrospective study was conducted in Spain with 710 women, of which 109 were obese (BMI > 30) and 601 were normoweight (BMI < 25). Consecutive nonrandom sampling. Variables: maternal age, BMI, gestational age, fetal position, start of labor, dilation and expulsion times, type of delivery and newborn weight and height. Results: The dilation time in obese women (309.81 ± 150.42 min) was longer than that in normoweight women (281.18 ± 136.90 min) (p = 0.05, Student's t-test). A higher fetal weight was more likely to lead to longer dilation time (OR = 0.43, 95% CI 0.010-0.075, p < 0.001) and expulsion time (OR = 0.027, 95% CI 0.015-0.039, p < 0.001). A higher maternal age was more likely to lead to a longer expulsion time (OR = 2.054, 95% CI 1.17-2.99, p < 0.001). Obese women were more likely to have gestational diabetes [relative risk (RR) = 3.612, 95% CI 2.102-6.207, p < 0.001], preeclampsia (RR = 5.514, 95% CI 1.128-26.96, p = 0.05), induced birth (RR = 1.26, 95% CI 1.06-1.50, p = 0.017) and cesarean section (RR = 2.16, 95% CI 1.11-4.20, p = 0.022) than normoweight women. Conclusion: Obesity is associated with increased complications during pregnancy, an increased incidence of a cesarean section and induced birth but it has no significant effect on the delivery time.

Physiologic childbirth and active management of the third stage of labor: A latent class model of risk for postpartum hemorrhage

BACKGROUND

Postpartum hemorrhage (PPH) is a threat to maternal mortality worldwide. Evidence supports active management of third stage labor (AMTSL) for preventing PPH. However, trials of AMTSL include women at varying risk levels, such as women undergoing physiologic labor and those with labor complications. Counseling women about their risk for PPH and AMTSL is difficult as many women who appear low-risk can still have PPH.

METHODS

This study uses outcomes of 2322 vaginal births from a hospital midwifery service in the United States to examine risks for PPH and effectiveness of AMTSL. Using a latent class analysis approach, physiologic birth practices and other risk factors for PPH were analyzed to understand if discrete classes of clinical characteristics would emerge. The effect of AMTSL on the PPH outcome was also considered by class.

RESULTS

A four-class solution best fit the data; each class was clinically distinct. The two largest Classes (A and B) represented women with term births and lower average parity, with higher rates of nulliparity in Class B. Class A women had more physiologic birth elements and less labor induction or labor dysfunction compared with Class B. PPH and AMTSL use was higher in Class B. In Class B, AMTSL lowered risk for PPH. However, in Class A, AMTSL was associated with higher risk for PPH and delayed placental delivery (>30 minutes).

DISCUSSION

AMTSL may not be as beneficial to women undergoing physiologic birth. Further study of the etiology of PPH in these women is indicated to inform preventive care.

Update on uterine tachysystole

Uterine tachysystole (TS) is a potentially significant intrapartum complication seen most commonly in induced or augmented labors but may also occur in women with spontaneous labor. When it occurs, maternal and perinatal complications can arise if not identified and managed promptly by obstetric care providers. Over recent years, new definitions of the condition have facilitated further research into the field, which has been synthesized to inform clinical management guidelines and protocols. We propose a set of recommendations pertaining to TS in line with contemporary evidence and obstetric practice.

Continuous oxytocin versus intermittent oxytocin for induction of labor: a randomized study

Objective: To assess whether intermittent usage of oxytocin infusion increases the duration of the active phase of labor and reduces maternal and neonatal complications or not.Materials and Methods: A prospective randomized controlled study was conducted of 200 consenting women with singleton pregnancy in the vertex position undergoing labor induction or augmentation at the Zeynep Kamil Maternity and Children's Training and Research Hospital. Participants with cervical dilation of 3 cm were randomized to either continued or intermittent oxytocin infusion when cervical dilation reached 5 cm. The primary outcome measures were the duration of the active phase of labor, defined as the period of labor from 5 cm of cervical dilation to vaginal delivery. Secondary outcomes were the duration of oxytocin infusion, mode of delivery, hyperstimulation, abnormalities in fetal heart rate, perineal tears, and neonatal outcomes.Results: The median duration of the active phase for the women with a vaginal delivery was longer in the intermittent oxytocin group than the continued oxytocin group, but it was not statistically significant (median, 6.91 vs. 7.58 h, p = .37). There was a significant difference in the duration of oxytocin infusion (median, 12.38 h in the intermittent group vs. 15.79 h in the continued group, p = .005). The incidence of uterine hyperstimulation was significantly greater in the continued group (21.1%) than the intermittent oxytocin group (3.8%) (p=.001).Conclusions: Intermittent usage of oxytocin infusion seems to make labor less complicated without lengthening duration of labor.

Discontinuation of intravenous oxytocin in the active phase of induced labour

BACKGROUND

In most Western countries, obstetricians and midwives induce labour in about 25% of pregnant women. Oxytocin is an effective drug for this purpose, but associated with serious adverse effects of which uterine tachysystole, fetal distress and the need for immediate delivery are the most common. Various administration regimens such as reduced or pulsatile dosing have been suggested to minimise these. Discontinuation in the active phase of labour, i.e. when contractions are well-established and the cervix is dilated at least 5 cm is another method which may reduce adverse effects.

OBJECTIVES

To assess whether birth outcomes can be improved by discontinuation of intravenous (IV) oxytocin, initiated in the latent phase of induced labour, once active phase of labour is established.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register (31 January 2018), Scopus, ClinicalTrials.gov, and the WHO International Clinical Trials Registry Platform (ICTRP) (23 January 2018) together with reference checking, citation searching, and contact with study authors to identify additional studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing discontinued IV with continuous IV oxytocin in the active phase of induced labour.No exclusion criteria were applied in terms of parity, maternal age, ethnicity, co-morbidity status, labour setting, gestational age, and prior caesarean delivery.Studies comparing different dosage regimens are outside the scope of this review.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods.

MAIN RESULTS

We found 10 completed RCTs involving 1888 women. One additional trial is ongoing. The included trials were conducted in hospital settings between February 1998 and January 2016, two in Europe (Denmark, and Greece), two in Turkey, and one each in Israel, Iran, USA, Bangladesh, India, and Thailand. Most trials included full-term singleton pregnancies with a fetus in vertex presentation. Some excluded women with cervical priming prior to induction and some excluded women with a history of prior caesarean delivery. When reported, the average age of the women ranged from 22 to 31 years, nulliparity from 45% to 68%, and pre-pregnancy body mass index from 22 to 32.Many of the included trials had design limitations and were judged to be at either high or unclear risk of bias across a number of 'Risk of bias' domains.Four trials included a Consort flow diagram. In three, this gave details of participants delivered before the active phase of labour, and treatment compliance for those who reached that stage. One Consort diagram only provided the latter information. The data in many of the trials without such a flow diagram were implausibly compliant with treatment allocation, suggesting that there had been silent post randomisation exclusions of women delivered before the active phase of labour. We therefore conducted a secondary analysis (not in our protocol) of caesarean section among women who reached the active phase of labour and were therefore eligible for the intervention.Our analysis by 'intention-to-treat' found that, compared with continuation of IV oxytocin stimulation, discontinuation of IV oxytocin may reduce the caesarean delivery rate, risk ratio (RR) 0.69, 95% confidence interval (CI) 0.56 to 0.86, 9 trials, 1784 women, low-level certainty. However, restricting our analysis to women who reached the active phase of labour (using 'reached active phase' as our denominator) suggests there is probably little or no difference between groups (RR 0.92, 95% CI 0.65 to 1.29, 4 trials, 787 women, moderate-certainty evidence).Discontinuation of IV oxytocin probably reduces the risk ofuterine tachysystole combined with abnormal fetal heart rate (FHR) compared with continued IV oxytocin (RR 0.15, 95% CI 0.05 to 0.46, 3 trials, 486 women, moderate-level certainty). We are uncertain about whether or not discontinuation increases the risk of chorioamnionitis (average RR 2.32, 95% CI 0.99 to 5.45, 1 trial, 252 women, very low-level certainty). Discontinuation of IV oxytocin may have little or no impact on the use of analgesia and epidural during labour compared to the use of continued IV oxytocin (RR 1.04 95% CI 0.95 to 1.14, 3 trials, 556 women, low-level certainty). Intrapartum cardiotocography (CTG) abnormalities (suspicious/pathological CTGs) are probably reduced by discontinuing IV oxytocin (RR 0.65, 95% CI 0.51 to 0.83, 7 trials, 1390 women, moderate-level certainty). Compared to continuing IV oxytocin, discontinuing IV oxytocin probably has little or no impact on the incidence of Apgar < 7 at five minutes (RR 0.78, 95% CI 0.27 to 2.21, 4 trials, 893 women, low-level certainty), or and acidotic cord gasses at birth (arterial umbilical pH < 7.10), (RR 1.03, 95% CI 0.50 to 2.13, 4 trials, 873 women, low-level certainty).Many of this review's maternal and infant secondary outcomes (including maternal and neonatal mortality) were not reported in the included trials.

AUTHORS' CONCLUSIONS

Discontinuing IV oxytocin stimulation after the active phase of labour has been established may reduce caesarean delivery but the evidence for this was low certainty. When restricting our analysis to those trials that separately reported participants who reached the active phase of labour, our results showed there is probably little or no difference between groups. Discontinuing IV oxytocin may reduce uterine tachysystole combined with abnormal FHR.Most of the trials had 'Risk of bias' concerns which means that these results should be interpreted with caution. Our GRADE assessments ranged from very low certainty to moderate certainty. Downgrading decisions were based on study limitations, imprecision and indirectness.Future research could account for all women randomised and, in particular, note those who delivered before the point at which they would be eligible for the intervention (i.e. those who had caesareans in the latent phase), or because labour was so rapid that the infusion could not be stopped in time.Future trials could adopt the outcomes listed in this review including maternal and neonatal mortality, maternal satisfaction, and breastfeeding.

Oxytocin discontinuation after the active phase of induced labor: A systematic review

BACKGROUND

Oxytocin is the most widely used drug in the induction of labor, but it could have potential adverse effects that derive from uterine hyperstimulation.

AIM

To determine the benefits and drawbacks of oxytocin continuation versus oxytocin discontinuation after the active phase of induced labor.

METHODS

We systematically searched Pubmed, EMBASE, Scopus, ClinicalTrials.gov and Cochrane Library Plus until October 2017, for randomized controlled trials comparing oxytocin continuation with oxytocin discontinuation when the active phase of labor is reached were included. Data was collected by three reviewers and quality of the included studies assessed using the methodology recommended in the Cochrane Handbook. StatsDirect software was used to calculate risk ratios for binary variables and weighted mean differences for continuous variables. A fixed-effects or random-effects model was used as appropriate.

RESULTS

Nine studies were selected including 1538 women, 774 in the oxytocin continuation group and 764 in the oxytocin discontinuation group. The incidence of cesarean sections (14.3% vs. 8.6%; relative risk, 1.67; 95% confidence interval: 1.25-2.23), uterine hyperstimulation (12.4% vs. 4.7%; relative risk, 2.59; 95% confidence interval: 1.70-3.93) and nonreassuring fetal heart rate (19.2% vs.12.5%; relative risk, 1.55; 95% confidence interval: 1.18-2.02) were significantly higher in the oxytocin continuation group. An increase in the duration of the second stage of labor in the oxytocin discontinuation group was observed (pooled mean difference, -7.03; 95% confidence interval: -9.80 to -4.26).

CONCLUSIONS

After the active phase of induced labor, oxytocin continuation increases the risk of cesarean section, uterine hyperstimulation and alterations to the fetal heart rate.

Factors associated with obstetric anal sphincter injuries in midwife-led birth: A cross sectional study

INTRODUCTION

Obstetric anal sphincter injurie (OASI) in vaginal births are a serious complication, and are associated with maternal morbidity. Focus on modifiable factors in midwives clinical skills and competences contributing to prevent the occurrence of OASI are essential. The objective of this study was to investigate the association between OASI and factors related to midwife-led birth such as manual support of perineum, active delivery of baby's shoulders, maternal birth position, and pushing and breathing techniques in second stage of labour.

METHODS

A prospective cross sectional study including primiparous (n = 129) and multiparous (n = 628) women in midwife-led non-instrumental deliveries with OASI (n = 96) or intact perineum (n = 661). Data were collected in a university hospital in Norway with two different birth settings: an alongside midwife-led unit with approximately 1500 births per year and an obstetrical unit with approximately 3500 births per year. In midwife-led births, there were a total of 2.6% OASI and 18.9% intact perineum.

RESULTS

The sample consisted of 757 women, 12.7% suffered OASI and 87.3% of participating women had an intact perineum. This selected sample compares the most serious outcome (OASI), and the optimal outcome (intact perineum).In primiparous women, 61 women suffered OASI and 68 women had intact perineum, while for multipara women, 35 women suffered OASI and 593 women had intact perineum. There was an increased risk of OASI if women actively pushed when the head was crowning compared to breathing the head out (adjusted OR: 3.10; 95% CI: 1.75 to 5.47). The maternal birth position associated with the lowest risk of OASI was kneeling position (adjusted OR: 0.15; 95% CI: 0.03 to 0.70), supine maternal birth position (adjusted OR: 2.52; 95% CI: 1.04 to 4.90) and oxytocin augmentation more than 30 min in second stage (OR: 1.93; 95% CI: 1.68 to 15.63) were associated with an increased risk of OASI, when adjusting for maternal, foetal, and obstetric factors.

CONCLUSION

Our study suggests that actively pushing when the baby's head is crowning, a supine maternal birth position and oxytocin augmentation more than 30 min in second stage, were associated with increased risk of OASI when compared to intact perineum. A kneeling maternal birth position was associated with a decreased risk of OASI.

Discontinuing Oxytocin Infusion in the Active Phase of Labor: A Systematic Review and Meta-analysis

OBJECTIVE

To evaluate the benefits and harms of discontinuation of oxytocin after the active phase of labor is reached.

DATA SOURCES

Electronic databases (ie, MEDLINE, Scopus, ClinicalTrials.gov, EMBASE, ScienceDirect, the Cochrane Library at the CENTRAL Register of Controlled Trials, Scielo) were searched from their inception until April 2017.

METHODS OF STUDY SELECTION

We included all randomized controlled trials comparing discontinuation (ie, intervention group) and continuation (ie, control group) of oxytocin infusion after the active phase of labor is reached, either after induction or augmentation of labor. Discontinuation of oxytocin infusion was defined as discontinuing oxytocin infusion when the active phase of labor was achieved. Continuation of oxytocin infusion was defined as continuing oxytocin infusion until delivery. Only trials in singleton gestations with vertex presentation at term were included. The primary outcome was the incidence of cesarean delivery.

TABULATION, INTEGRATION, AND RESULTS

Nine randomized controlled trials, including 1,538 singleton gestations, were identified as relevant and included in the meta-analysis. All nine trials included only women undergoing induction of labor. In the discontinuation group, if arrest of labor occurred, usually defined as no cervical dilation in 2 hours or inadequate uterine contractions for 2 hours or more, oxytocin infusion was restarted. Women in the control group had oxytocin continued until delivery usually at the same dose used at the time the active phase was reached. Women who were randomized to have discontinuation of oxytocin infusion after the active phase of labor was reached had a significantly lower risk of cesarean delivery (9.3% compared with 14.7%; relative risk 0.64, 95% CI 0.48-0.87) and of uterine tachysystole (6.2% compared with 13.1%; relative risk 0.53, 95% CI 0.33-0.84) compared with those who were randomized to have continuation of oxytocin infusion until delivery. Discontinuation of oxytocin infusion was associated with an increase in the duration of the active phase of labor (mean difference 27.65 minutes, 95% CI 3.94-51.36).

CONCLUSION

In singleton gestations with cephalic presentation at term undergoing induction, discontinuation of oxytocin infusion after the active phase of labor at approximately 5 cm is reached reduces the risk of cesarean delivery and of uterine tachysystole compared with continuous oxytocin infusion. Given this evidence, discontinuation of oxytocin infusion once the active stage of labor is established in women being induced should be considered as an alternative management plan.

Augmentation of Labor: A Review of Oxytocin Augmentation and Active Management of Labor

Labor augmentation can be used to hasten labor, shorten the time to delivery, and perhaps reduce the risk of cesarean delivery. Particularly in women with longer labors or less frequent contractions, oxytocin augmentation seems to have positive impacts on these outcomes. Despite this, the evidence for augmentation alone on the risk of cesarean delivery is unclear, with varying evidence. More recently, oxytocin protocols have been recommended to standardize care and ensure patient safety.

Titration of intravenous synthetic oxytocin post vaginal birth following induction or augmentation

Evidence exists for titration of intravenous oxytocin during induction and augmentation, whereas no evidence was identified for titration of intravenous oxytocin following vaginal birth, where management excluded oxytocin for postpartum haemorrhage (PPH). This retrospective cohort study explored this issue through patient case notes and computerised perinatal data. Analysis included 335 women comparing induction (n = 226, 67%) to augmentation (n = 109, 33%). The two groups differed in terms of: parity; oxytocin dosage; length of time on intravenous oxytocin; and the length of first and second stage labour. They had similar rates of PPH and titration of intravenous oxytocin following birth was rarely recorded.