Caesarean section at full dilatation: incidence, impact and current management

Impacted fetal head extraction methods at second stage cesarean and subsequent preterm delivery: A multicenter study

OBJECTIVE

Second-stage cesarean delivery (CD) is associated with subsequent preterm birth (PTB). It has been suggested that an increased risk of PTB after second-stage cesarean delivery could be linked to a higher chance of cervical injury due to the extension of the uterine incision. Previous studies have shown that reverse breech extraction is associated with lower rates of uterine incision extensions compared to the "push" method. We aimed to investigate the association between the method of fetal extraction during second-stage CD and the rate of spontaneous PTB (sPTB), as well as other maternal and neonatal outcomes during the subsequent pregnancy.

METHODS

This was a multicenter retrospective cohort study. The study population included women in their first subsequent singleton delivery following a second-stage CD between 2004 and 2021. The main exposure of interest was the method of fetal extraction in the index CD ("push" method vs. reverse breech extraction). The primary outcome of this study was sPTB <37 weeks in the subsequent pregnancy. Secondary outcomes were overall PTB, trial of labor, and other adverse maternal and neonatal outcomes. Univariate analysis was followed by multiple logistic regression modeling.

RESULTS

During the study period, 2969 index CD during second stage were performed, of those 583 met the inclusion criteria, of whom 234 (40.1%) had fetal extraction using the reverse breech extraction method, while 349 (59.9%) had the "push" method for extraction. In univariate analysis, women in those two groups had statistically similar rates of sPTB (3.7% vs. 3.0%; odds ratio [OR] 1.25, 95% CI: 0.49-3.19) and overall PTB (<37, <34 and <32 weeks), as well as other maternal, neonatal, and trial of labor outcomes. This was confirmed by multivariate analyses with an adjusted OR of 1.27 (95% CI: 0.43-3.71) for sPTB.

CONCLUSION

Among women with a previous second-stage CD, no significant difference was observed in PTB rates in the subsequent pregnancies following the "push" method compared to the reverse breech extraction method.

Prediction of spontaneous preterm birth in women with previous full dilatation cesarean delivery

BACKGROUND

A previous term (≥37 weeks' gestation), full-dilatation cesarean delivery is associated with an increased risk for a subsequent spontaneous preterm birth. The mechanism is unknown. We hypothesized that the cesarean delivery scar characteristics and scar position relative to the internal cervical os may compromise cervical function, thereby leading to shortening of the cervical length and spontaneous preterm birth.

OBJECTIVE

This study aimed to determine the relationship of cesarean delivery scar characteristics and position, assessed by transvaginal ultrasound, in pregnant women with previous full-dilatation cesarean delivery with the risk of shortening cervical length and spontaneous preterm birth.

STUDY DESIGN

This was a single-center, prospective cohort study of singleton pregnant women (14 to 24 weeks' gestation) with a previous term full-dilatation cesarean delivery who attended a high-risk preterm birth surveillance clinic (2017-2021). Women underwent transvaginal ultrasound assessment of cervical length, cesarean delivery scar distance relative to the internal cervical os, and scar niche parameters using a reproducible transvaginal ultrasound technique. Spontaneous preterm birth prophylactic interventions (vaginal cervical cerclage or vaginal progesterone) were offered for short cervical length (≤25 mm) and to women with a history of spontaneous preterm birth or late miscarriage after full-dilatation cesarean delivery. The primary outcome was spontaneous preterm birth; secondary outcomes included short cervical length and a need for prophylactic interventions. A multivariable logistic regression analysis was used to develop multiparameter models that combined cesarean delivery scar parameters, cervical length, history of full-dilatation cesarean delivery, and maternal characteristics. The predictive performance of models was examined using the area under the receiver operating characteristics curve and the detection rate at various fixed false positive rates. The optimal cutoff for cesarean delivery scar distance to best predict a short cervical length and spontaneous preterm birth was analyzed.

RESULTS

Cesarean delivery scars were visualized in 90.5% (220/243) of the included women. The spontaneous preterm birth rate was 4.1% (10/243), and 12.8% (31/243) of women developed a short cervical length. A history- (n=4) or ultrasound-indicated (n=19) cervical cerclage was performed in 23 of 243 (9.5%) women; among those, 2 (8.7%) spontaneously delivered prematurely. A multiparameter model based on absolute scar distance from the internal os best predicted spontaneous preterm birth (area under the receiver operating characteristics curve, 0.73; 95% confidence interval, 0.57-0.89; detection rate of 60% for a fixed 25% false positive rate). Models based on the relative anatomic position of the cesarean delivery scar to the internal os and the cesarean delivery scar position with niche parameters (length, depth, and width) best predicted the development of a short cervical length (area under the receiver operating characteristics curve, 0.79 [95% confidence interval, 0.71-0.87]; and 0.81 [95% confidence interval, 0.73-0.89], respectively; detection rate of 73% at a fixed 25% false positive rate). Spontaneous preterm birth was significantly more likely when the cesarean delivery scar was <5.0 mm above or below the internal os (adjusted odds ratio, 6.87; 95% confidence interval, 1.34-58; P =.035).

CONCLUSION

In pregnancies following a full-dilatation cesarean delivery, cesarean delivery scar characteristics and distance from the internal os identified women who were at risk for spontaneous preterm birth and developing short cervical length. Overall, the spontaneous preterm birth rate was low, but it was significantly increased among women with a scar located <5.0 mm above or below the internal cervical os. Shortening of cervical length was strongly associated with a low scar position. Our novel findings indicate that a low cesarean delivery scar can compromise the functional integrity of the internal cervical os, leading to cervical shortening and/or spontaneous preterm birth. Assessment of the cesarean delivery scar characteristics and position seem to have use in preterm birth clinical surveillance among women with a previous, full-dilatation cesarean delivery and could better identify women who would benefit from prophylactic interventions.

Risk of spontaneous preterm birth elevated after first cesarean delivery at full dilatation: a retrospective cohort study of over 30,000 women

BACKGROUND

Having a cesarean delivery at full dilatation has been associated with increased subsequent risk of spontaneous preterm birth. The Aberdeen Maternity and Neonatal Databank provides a rare opportunity to study subsequent pregnancy outcomes after a previous cesarean delivery at full dilatation over 40 years, with an ability to include a detailed evaluation of potential confounding factors.

OBJECTIVE

This study aimed to investigate if having an initial cesarean delivery at full dilatation is associated with spontaneous preterm birth or other adverse pregnancy outcomes in the subsequent pregnancy.

STUDY DESIGN

A retrospective cohort study was conducted including women with a first and second pregnancy recorded within the Aberdeen Maternity and Neonatal Databank between 1976 and 2017, where previous cesarean delivery at full dilatation at term in the first birth was the exposure. The primary outcome was spontaneous preterm birth (defined as spontaneous birth <37 weeks). Multivariate logistic regression was used to investigate any association between cesarean delivery at full dilatation and the odds of spontaneous preterm birth. Cesarean delivery at full dilatation in previous pregnancy was compared with: (1) any other mode of birth, and (2) individual modes of birth, including planned cesarean delivery, cesarean delivery in first stage of labor (<10-cm dilatation), and vaginal birth (including spontaneous vaginal birth, nonrotational forceps, Kielland forceps, vacuum-assisted birth, breech vaginal birth). Other outcomes such as antepartum hemorrhage and mode of second birth were also compared.

RESULTS

Of the 30,253 women included, 900 had a previous cesarean delivery at full dilatation in the first pregnancy. Women with previous cesarean delivery at full dilatation had a 3-fold increased risk of spontaneous preterm birth in a second pregnancy (unadjusted odds ratio, 2.63; 95% confidence interval, 1.82-3.81; adjusted odds ratio, 3.31; 95% confidence interval, 2.17-5.05) compared with those with all other modes of first birth, adjusted for maternal age, diabetes mellitus, body mass index, smoking, preeclampsia, antepartum hemorrhage, socioeconomic deprivation (Scottish Index of Multiple Deprivation 2016), year of birth, and interpregnancy interval (in second pregnancy). When compared with women with vaginal births only, women with cesarean delivery at full dilatation had 5-fold increased odds of spontaneous preterm birth (adjusted odds ratio, 5.37; 95% confidence interval, 3.40-8.48). Compared with first spontaneous vaginal birth, first instrumental births (nonrotational forceps, Kielland forceps, and vacuum births) were not associated with increased risk of spontaneous preterm birth in the second birth. After an initial cesarean delivery at full dilatation, 3.7% of women had a repeated cesarean delivery at full dilatation and 48% had a planned cesarean delivery in the second birth.

CONCLUSION

This study is a substantial addition to the body of evidence on the risk of subsequent spontaneous preterm birth after cesarean delivery at full dilatation, and demonstrates a strong association between cesarean delivery at full dilatation in the first birth and spontaneous preterm birth in subsequent pregnancy, although the absolute risk remains small. This is a large retrospective cohort and includes a comprehensive assessment of potential confounding factors, including preeclampsia, antepartum hemorrhage, and lengths of first and second stage of labor. Future research should focus on understanding possible causality and developing primary and secondary preventative measures.

Cesarean section in the second stage of labor is associated with early-term and late preterm birth in subsequent pregnancies

OBJECTIVES

The objectives of this study were to determine in a population-based cohort study the association between cesarean section (CS) during the second stage of labor and the risk for preterm birth and/or cervical insufficiency in the subsequent pregnancy; to identify maternal and neonatal risk factors for long-term complications following CS due to prolonged second stage of labor.

METHODS

We conducted a retrospective population-based cohort study including women who had at least one consecutive delivery following a CS at our institution from 1991 to 2018, provided that the first delivery was at term. We divided the study cohort into two groups: (1) women who delivered by CS due to failure to progress during the first stage of labor (n = 1068); and (2) those who delivered by CS due to arrest of descent at the second stage of labor (n = 603).

RESULTS

Of the 120,147 women who met the inclusion criteria, 78,407 had a subsequent delivery during the study period. Women of group 1 were significantly older than those of group 2 (p = .018), and had a higher rate of assisted reproductive technology [61 (5.7%) vs. 18 (3.1%), p < .022,]. Additionally, their hospitalization period was significantly longer (p < .001). The rate of preterm birth in the subsequent delivery was higher among women who had a CS due to arrest of descent than those who had a CS due to arrest in dilatation [43 (7.3%) vs 49 (4.6%), p < .026]. This was confirmed after adjusting for confounding factors In a multivariable regression analysis (OR 1.78, 95% CI 1.14-2.76, p value = .011) A Cox regression analysis implying gestational age at delivery at the time factor identifies CS due to arrest of descent as a risk factor for subsequent preterm birth (Hazard ratio 1.19 95% CI 1.07-1.31).

CONCLUSION

CS due to arrest of descent is an independent risk factor for subsequent preterm birth. The exact mechanisms contributing to this association are yet to be determined.

SYNOPSIS

Cesarean section during the second stage of labor is an independent risk factor for late preterm birth in the subsequent pregnancy when compared to cesarean section in the first stage of labor.

Obstetrics Outcomes in Women Undergoing Second-Stage Cesarean Section: A Cross-Sectional Study

Background Cesarean section (CS) involves the delivery of the fetus through incisions in the abdomen or uterine walls which is an alternative to vaginal delivery. In the majority of women, second-stage CS is performed without even attempting assisted vaginal delivery. This leads to difficulty for obstetricians for whether to perform an immediate CS or attempt a difficult vaginal birth as the effective method of delivery as CS are linked with higher morbidities which further increase when a CS is performed in the second stage. Hence, the present study was performed to find out obstetrics results in women undergoing second-stage CS. Method A cross-sectional study was conducted in the Department of Obstetrics and Gynecology of a tertiary care center attached to a medical college to study obstetric outcomes in women undergoing second-stage CS from January 2021 to December 2022 on 54 postnatal women who underwent second-stage CS. Results The mean age was 26.7 ± 3.9 years ranging between 19 and 35 years involving a majority of primiparity women. Maximum patients were having gestational age between 39 and 40 weeks and had spontaneous labor. The main indication of second-stage CS was non-reassuring fetal status and the method of delivery mainly involved for the deeply impacted head was the modified patwardhan technique in which if the head is embedded deeply in the pelvis in the OP position the anterior shoulder is delivered first followed by the same side leg then opposite side leg followed by the arm is gently delivered. Baby's trunk, legs, and buttocks are moved out by pulling them carefully and gently. And lastly, the head of the infant is finally moved out. The intra-operative complications mainly found were an extension of uterine angle and the post-operative complication was post-partum hemorrhage (PPH). The most common neonatal complication was the requirement for neonatal intensive care unit (NICU) admission. In conclusion, the present study reported a hospital range between seven and 14 days in comparison to other studies that reported hospital stays between three and 15 days. Conclusion In conclusion, higher maternal and fetal morbidities were associated with CS performed at full dilation of the cervix. The most common maternal complication seen was an injury to uterine vessels along with PPH however neonatal complications included the requirement of NICU monitoring. As there are no appropriate guidelines for the same, formulation of guidelines for performing CS at full dilation is required.

A retrospective cohort study of the characteristics of unsuccessful operative vaginal deliveries

INTRODUCTION

Unsuccessful operative vaginal delivery (OVD) is associated with high rates of materno-fetal morbidity. We aimed to examine institutional rates of unsuccessful OVDs (uOVD) and compare them with successful OVD (sOVD) in order to identify factors to aid patient selection and education.

METHODS

A 6-month retrospective cohort study was performed on all unsuccessful and successful OVDs in a tertiary level maternity hospital in the Republic of Ireland. Maternal demographics and obstetric factors were assessed to evaluate potential underlying risk factors for unsuccessful operative vaginal delivery versus successful vaginal delivery.

RESULTS

There were 4,191 births during the study period with an OVD rate of 14.2% (n = 595) with 28 (4.7% of OVDs) being unsuccessful. Unsuccessful OVD were predominately nulliparous (25; 89.2%) with a mean maternal age of 30.1 years (range 20-42), with more than half (n = 15, 53.5%) being induced. The most common indication for induction was prolonged rupture of membranes (PROM) (n = 7, 25%) which was significantly different from the successful OVD group. A senior obstetrician was significantly more likely to be the primary operator in uOVD when compared to sOVD. (82.1 % V 54.1% p < 0.01). The majority of unsuccessful OVD were vacuum deliveries (n = 17; 60.7%), with a significantly higher mean birthweight when compared to successful OVD (3.695 kg V 3.483 kg; p < 0.01). Following an unsuccessful OVD, women were more likely to have a postpartum haemorrhage (64.2 % V 31.5% p < 0.01) and their infant was more likely to require admission to the neonatal intensive care unit (NICU) (32.1 % V 5.8% p < 0.01) when compared with successful OVD.

CONCLUSION

Risk factors for unsuccessful OVD were higher birth weight and induction of labour. There was a higher incidence of postpartum haemorrhage and NICU admission when compared with successful OVD.

Decreasing urgent repeat cesarean sections by offering complimentary ultrasounds and consultation in rural Burundi: The zigama mama project

Objective

Repeat urgent cesarean sections (CS) carry an increased risk of severe maternal outcomes. As CS increase in sub-Saharan Africa, creative strategies are necessary to reduce the rate of urgent repeat CS. The Zigama-Mama Project in rural Burundi uses complimentary ultrasounds to create a clinical touchpoint to counsel women with a prior CS for a hospital-based delivery.

Methods

From July 2019 to June 2020, complimentary ultrasounds were offered to all antenatal patients with prior CS, along with counseling for monitored trial of labor after cesarean (TOLAC) or scheduled repeat CS. Community engagement and feedback from district health centers were evaluated.

Results

In total, 500 women with a prior CS presented for a complimentary ultrasound. During the intervention year, a relative and absolute reduction in urgent repeat CS (baseline: n = 114 {70.8%}, intervention: n = 97{49.7%}, p < 0.001) was observed, with no significant change in maternal mortality or ruptured uteri. All health center personnel agreed the project improved their confidence in referring women with prior CS.

Conclusion

Offering complimentary ultrasounds as a clinical touchpoint for scheduling a monitored delivery or CS for women at high risk for delivery complication may be an affordable and creative strategy to care for women with previous CS during subsequent deliveries.

Reproducibility of assessment of full-dilatation Cesarean section scar in women undergoing second-trimester screening for preterm birth

OBJECTIVE

To assess the reproducibility of a standardized method of measuring the Cesarean section (CS) scar, CS scar niche and their position relative to the internal os of the uterine cervix by transvaginal ultrasound in pregnant women with a previous full-dilatation CS.

METHODS

This was a prospective, single-center reproducibility study on women with a singleton pregnancy and a previous full-dilatation CS who underwent transvaginal ultrasound assessment of cervical length and CS scar characteristics at 14-24 weeks' gestation. The CS scar was identified as a hypoechogenic linear discontinuity of the myometrium at the anterior wall of the lower uterine segment or cervix. The CS scar niche was identified as an indentation at the site of the scar with a depth of at least 2 mm. The CS scar position was evaluated by measuring the distance to the internal cervical os. CS scar niche parameters, including its length, depth, width, and residual and adjacent myometrial thickness, were assessed in the sagittal and transverse planes. Qualitative reproducibility was assessed by agreement regarding visibility of the CS scar and niche. Quantitative reproducibility of CS scar measurements was assessed using three sets of images: (1) real-time two-dimensional (2D) images (real-time acquisition and caliper placement on 2D images by two operators), (2) offline 2D still images (offline caliper placement by two operators on stored 2D images acquired by one operator) and (3) three-dimensional (3D) volume images (volume manipulation and caliper placement on 2D images extracted by two operators). Agreement on CS scar visibility and the presence of a niche was analyzed using kappa coefficients. Intraobserver and interobserver reproducibility of quantitative measurements was assessed using Bland-Altman plots.

RESULTS

To achieve the desired statistical power, 72 women were recruited. The CS scar was visualized in > 80% of images. Interobserver agreement for scar visualization and presence of a niche in real-time 2D images was excellent (kappa coefficients of 0.84 and 0.85, respectively). Overall, reproducibility was higher for real-time 2D and offline 2D still images than for 3D volume images. The 95% limits of agreement (LOA) for intraobserver reproducibility were between ± 1.1 and ± 3.6 mm for all sets of images; the 95% LOA for interobserver reproducibility were between ± 2.0 and ± 6.3 mm. Measurement of the distance from the CS scar to the internal cervical os was the most reproducible 2D measurement (intraobserver and interobserver 95% LOA within ± 1.6 and ± 2.7 mm, respectively). Overall, niche measurements were the least reproducible measurements (intraobserver 95% LOA between ± 1.6 and ± 3.6 mm; interobserver 95% LOA between ± 3.1 and ± 6.3 mm). There was no consistent difference between measurements obtained by reacquisition of 2D images (planes obtained twice and caliper placed), caliper placement on 2D stored images or volume manipulation (planes obtained twice and caliper placed).

CONCLUSIONS

The CS scar position and scar niche in pregnant women with a previous full-dilatation CS can be assessed in the second trimester of a subsequent pregnancy using either 2D or 3D volume ultrasound imaging with a high level of reproducibility. Overall, the most reproducible CS scar parameter is the distance from the CS scar to the internal cervical os. The method proposed in this study should enable clinicians to assess the CS scar reliably and may help predict pregnancy outcome. © 2022 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Maternal and neonatal outcomes associated with delivery techniques for impacted fetal head at cesarean section: a systematic review and meta-analysis

OBJECTIVES

Late first-stage or second-stage cesarean section is commonly associated with fetal head impaction, leading to maternal and neonatal complications. This situation requires safe delivery techniques, but the optimal management remains controversial. The aim of this meta-analysis was to compare maternal and neonatal outcomes associated with delivery techniques via cesarean section.

METHODS

An electronic search of three databases, from inception to June 2021, was conducted. Cohort and randomised comparative studies on maternal and neonatal outcomes associated with techniques to deliver an impacted fetal head during cesarean section were included. The methodological quality of the primary studies was assessed. Review Manager 5.4 was used for statistical analyses.

RESULTS

Nineteen articles, including 2,345 women were analyzed. Three fetal extraction techniques were identified. Meta-analyses showed that the "pull" technique carries lower risks as compared to the "push" technique and the "Patwardhan" technique is safer compared to the "push" or the "push and pull" technique.

CONCLUSIONS

In the absence of robust evidence to support the use of a specific technique, the choice of the obstetrician should be based on best available evidence. Our study suggests that the "pull", as well as the "Patwardhan" technique represent safe options to deliver an impacted fetal head.

Second stage cesarean section and the risk of preterm birth in subsequent pregnancies

OBJECTIVE

To evaluate the risk of spontaneous preterm birth on subsequent pregnancies after second stage cesarean section.

METHODS

This is a retrospective cohort study. Women were included if they had their two consecutive births in Toulouse University Hospital in the study period. The first birth was a singleton livebirth at term (≥37 weeks of gestation), divided in three categories according to the mode of delivery: vaginal delivery (group A), cesarean section before the second stage of labor (group B), cesarean section during the second stage of labor (group C). The subsequent pregnancy was the first subsequent pregnancy, conducted after 16 weeks of gestation. The primary outcome was spontaneous preterm birth in the subsequent pregnancy, defined as delivery before 37 weeks of gestation. Secondary endpoints included preterm rupture of membranes in the subsequent pregnancy.

RESULTS

Between 2003 and 2018, 7776 women (84.7%) in group A, 1263 (13.8%) in group B and 143 (1.5%) in group C were included. The adjusted odds ratio of spontaneous preterm birth before 37 weeks of gestation after second stage cesarean section was 2.4 (group C vs group A + B, 95% confidence interval: 1.2-4.8), P = 0.01). The rate of preterm rupture of membranes was also significantly higher in group C (6% vs 2% in group A, P = 0.009, 6% vs 3% in group B, P= 0.05) with OR = 3.0 (group C vs group A + B, 95% CI: 1.55-6.16, P < 0.001).

CONCLUSION

History of term second stage of labor cesarean section is an independent risk factor for spontaneous preterm birth and for preterm rupture of membrane in the subsequent pregnancy.

Prior term delivery increases risk of subsequent recurrent preterm birth: An unexpected finding

Background

Women with a prior pregnancy at term are generally considered to be at reduced risk for subsequent spontaneous preterm birth (sPTB), whereas a previous sPTB is a major predictor for a future sPTB.

Aims

The objective of this study was to investigate the risk of recurrent sPTB in women with a prior term birth and a subsequent sPTB.

Materials and Methods

This is a retrospective cohort study conducted at St Thomas’ Hospital in London, UK. There were 430 women included: 230 with a term birth (caesarean section or vaginal delivery) preceding a sPTB (term + sPTB group) and 200 with a prior sPTB only (sPTB only group). The primary outcome was sPTB, <37 weeks gestation.

Results

Of the term + sPTB group, 38.7% (89/230) had a recurrent sPTB compared to 20% (40/200) in the sPTB only group (P < 0.0001), with a relative risk (RR) of 1.9. Of women who had a term caesarean section and a subsequent PTB, 50% (30/60) had a further sPTB (RR 2.5 compared to the sPTB only group), while 34.7% (59/170) of women who had a term vaginal birth and subsequent sPTB, had a further sPTB (RR 1.7 compared to the sPTB only group).

Conclusion

In women who have had a previous sPTB, the risk of a recurrence is much higher than in women with a prior term birth. The aetiology of PTB may be different in this subgroup of women and needs to be further elucidated to determine how best to identify and treat them.

Previous term emergency caesarean section is a risk factor for recurrent spontaneous preterm birth; a retrospective cohort study

OBJECTIVES

Emergency caesarean sections (EmCS), particularly those performed in the second stage of labour, have been associated with a risk of subsequent preterm birth. More worrying is that the risk of sPTB recurrence appears to be high in women who have had a second stage EmCS and a subsequent sPTB. However, there is a paucity of evidence regarding the risk of recurrence in women who have had a prior term EmCS at any stage of labour followed by a sPTB. This study aims to investigate the relationship between all term in labour EmCS and the risk of recurrent spontaneous preterm birth (sPTB).

STUDY DESIGN

This is an observational, retrospective cohort study conducted at St Thomas' Hospital, a tertiary-level maternity hospital in London, United Kingdom. 259 women were included; 59 women with a term in labour EmCS preceding a sPTB (EmCS group) and 200 women with a prior sPTB only (control group). The initial EmCS was further categorised into first stage (FS)-EmCS or second stage (SS)-EmCS. Primary outcome was sPTB in Pregnancy C < 37 weeks' gestation. Secondary outcomes included sPTB < 34 weeks' and < 24 weeks' gestation.

RESULTS

54% (32/59) of the EmCS group had a recurrent sPTB < 37 weeks compared to 20% (40/200) of the control women (p < 0.0001) with a relative risk of 2.71 [95%CI 1.87-3.87]). Of women who had a SS-EmCS and a subsequent PTB, 61.9% (13/21) had a further sPTB (RR 3.0 [95%CI, 1.8-4.5] compared to control women). In addition, there is nearly a 6-fold increased risk of a recurrent sPTB or midtrimester loss < 24 weeks' gestation in these women (RR 5.65 [95%CI2.6-12.0]).

CONCLUSIONS

In women who have had a previous sPTB in which a term in labour EmCS is a risk factor, the risk of a further sPTB is much higher than in those women where a prior sPTB is the sole risk factor. Furthermore, EmCS at both the first and second stage of labour are associated with a increased risk of recurrent sPTB. Further work should ascertain which women who have had a prior term EmCS are at risk of sPTB and recurrence, and how best to identify and treat them.

A comparison of technicques to disimpact the fetal head on a second stage caesearean simulator

Background

The rate of second stage caesarean section (CS) is rising with associated increases in maternal and neonatal morbidity, which may be related to impaction of the fetal head in the maternal pelvis. In the last 10 years, two devices have been developed to aid disimpaction and reduce these risks: the Fetal Pillow (FP) and the Tydeman Tube (TT). The aim of this study was to determine the distance of upward fetal head elevation achieved on a simulator for second stage CS using these two devices, compared to the established technique of per vaginum digital disimpaction by an assistant.

Methods

We measured elevation of the fetal head achieved with the two devices (TT and FP), compared to digital elevation, on a second stage Caesearean simulator (Desperate Debra ™ set at three levels of severity. Elevation was measured by both a single operator experienced with use of the TT and FP and also multiple assistants with no previous experience of using either device. All measurements were blinded

Results

The trained user achieved greater elevation of the fetal head at both moderate and high levels of severity with the TT (moderate: 30mm vs 12.5mm p<0.001; most severe: 25mm vs 10mm p<0.001) compared to digital elevation. The FP provided comparable elevation to digital at both settings (moderate: 10 vs 12.5mm p=0.149; severe 10 vs 10mm p=0.44).

With untrained users, elevation was also significantly greater with the TT compared to digital elevation (20mm vs 10mm p<0.01). However digital disimpaction was significantly greater than the FP (10mm vs 0mm p<0.0001).

Conclusion

On a simulator, with trained operators, the TT provided greater fetal head elevation than digital elevation and the FP. The FP achieved similar elevation to the digital technique, especially when the user was trained in the procedure.

Committee Opinion No. 415: Impacted Fetal Head, Second-Stage Cesarean Delivery

OBJECTIVE

To review the most effective clinical approaches to disengage an impacted fetal head during cesarean delivery.

TARGET POPULATION

Women who undergo cesarean delivery of an infant with a deeply impacted head.

OPTIONS

The "push" technique (from below) or the "pull" technique (reverse breech extraction).

OUTCOMES

Proper management of this clinical scenario can reduce maternal and perinatal morbidity and mortality.

BENEFITS, HARMS, AND COSTS

Using an evidence-informed approach when an impacted fetal head is anticipated has the potential to reduce maternal and fetal complications and short- and long-term harm and their associated costs. Research into the value of simulation learning, regular labour assessments, and team preparedness for possible interventions will help inform quality care.

EVIDENCE

The following search terms were entered into PubMed/Medline, Google Scholar, and Cochrane for the publication period 2012-2019: • 'Guidelines' 'manual' • 'Caesarean Section' • 'full dilation' • 'operative delivery' • 'impacted head' • 'Caesarean' AND 'full dilation' AND 'impacted head' • 'Caesarean' AND 'second stage of labour' OR 'second stage' AND 'impacted head' • 'Caesarean' OR 'operative delivery' AND 'impacted head' A total of 32 articles were retrieved and 24 were deemed appropriate to include as references. Many of these articles represented expert opinion. Randomized controlled trials had small sample sizes and were conducted in settings that limit the generalizability of their findings to the Canadian population.²⁰ INTENDED USERS: Intrapartum health care providers.

Opinion de comité n° 415 : Césarienne au deuxième stade avec enclavement de la tête fœtale

OBJECTIF

Passer en revue les stratégies cliniques les plus efficaces pour désengager une tête fœtale enclavée pendant la césarienne.

POPULATION CIBLE

Les femmes qui subissent une césarienne lorsque la tête fœtale est fortement enclavée.

OPTIONS

La technique par poussée (par le bas) ou par traction (grande extraction du siège par voie abdominale). RéSULTATS: La prise en charge adéquate de cette situation clinique peut réduire les risques de morbidité et mortalité maternelle et périnatale. BéNéFICES, RISQUES ET COûTS: Lorsque l'on anticipe un enclavement de la tête fœtale, il est possible de réduire le risque de complications maternelles et fœtales, les atteintes à court et à long terme ainsi que les coûts associés en adoptant une stratégie fondée sur des données probantes. Les recherches sur la valeur de l'apprentissage par simulation, les évaluations régulières pendant le travail et la préparation de l'équipe aux interventions possibles aideront à orienter les soins de qualité. DONNéES PROBANTES: Les termes de recherche suivants ont été utilisés dans les bases de données PubMed-Medline, Google Scholar et Cochrane pour la période de publication de 2012 à 2019 : • "Guidelines" "manual" • "Caesarean Section" • "full dilation" • "operative delivery" • "impacted head" • "Caesarean" AND "full dilation" AND "impacted head" • "Caesarean" AND "second stage of labour" OR "second stage" AND "impacted head" • "Caesarean" OR "operative delivery" AND "impacted head" Au total, 32 articles ont été récupérés et 24 ont été jugés adéquats comme références. Plusieurs de ces articles étaient des opinions d'experts. Les essais cliniques randomisés avaient des échantillons de petite taille et ont été menés dans des contextes qui limitent la généralisabilité de leurs résultats à la population canadienne²⁰.

PROFESSIONNELS CIBLES

Fournisseurs de soins de santé intrapartum.

Comparison of perinatal outcomes for all modes of second stage delivery in obstetric theatres: a retrospective observational study

OBJECTIVE

To compare rates of vaginal delivery and adverse outcomes of instrumental delivery trials in obstetric theatre compared to primary emergency full dilation caesarean section.

DESIGN

Retrospective cohort study.

SETTING

University teaching hospital.

POPULATION

Women with singleton, non-anomalous, pregnancy undergoing instrumental delivery trial in obstetric theatre.

METHODS

Data were collected from consecutive cases during 2014 until 2018 using clinical records. Multivariate regression analysis was used comparing outcomes per first delivery method.

MAIN OUTCOME MEASURES

Primary outcome was completion of vaginal delivery between all methods of instrumental delivery. Secondary outcome was a composite of immediate perinatal adverse outcomes for instrumental delivery modes and primary full dilation caesarean section.

RESULTS

From 971 deliveries analysed: ventouse delivery was significantly less likely to achieve vaginal delivery compared with Keilland's forceps delivery (odds ratio [OR] 0.42, 95% CI 0.22-0.79). Once confounding factors were adjusted for, adverse outcome rates were less frequent in the Keilland's forceps group than with primary full dilation caesarean section (OR 0.37, 95% CI 0.16-0.81); however, the receiver operating characteristic curve produced from this model demonstrated a low predictive value (AUC 0.64).

CONCLUSIONS

Attempting instrumental delivery in delivery suite theatre, as an alternative to primary emergency full dilation caesarean section, is both reasonable and safe. In this study, ventouse delivery performed poorly in comparison with other modes of instrumental delivery. Further research in the form of randomised controlled trials to identify the optimal mode of second stage delivery is paramount.

TWEETABLE ABSTRACT

Instrumental delivery trials in theatre are safe but use of ventouse was associated with a higher rate of failure.

Risks associated with cesarean delivery during prolonged second stage of labor

BACKGROUND

Data regarding maternal and fetal morbidities are limited to surgical morbidity per each additional hour in the second stage of labor.

OBJECTIVE

This study aimed to quantify perinatal morbidities associated with cesarean delivery by duration of the second stage of labor.

STUDY DESIGN

Our work is a retrospective cohort study of cesarean deliveries during the second stage of labor using the Consortium on Safe Labor database. All term, singleton pregnancies in cephalic presentation were included. Women with stillbirth or contraindications to vaginal delivery were excluded. Groups were divided by duration of the second stage of labor: ≤3 hours, 3-4 hours, 4-5 hours, 5-6 hours, and >6 hours. The primary outcome was a composite of maternal morbidities. The secondary outcomes were a composite of neonatal morbidities and individual maternal and neonatal morbidities. Baseline demographic and clinical characteristics were compared among groups. Univariate and multivariate analyses were performed.

RESULTS

We included 6273 women in total. In addition, 3652 women (58.2%) went through the second stage for ≤3 hours, 854 (13.6%) for 3 to 4 hours, 618 (9.9%) for 4 to 5 hours, 397 (6.3%) for 5 to 6 hours, and 752 (12.0%) for >6 hours. Neither the maternal nor neonatal morbidity composite outcomes were statistically different among the groups. Extended maternal length of stay (>5 days), increased birthweight, and lower rates of general anesthesia were associated with an increased duration of the second stage of labor. Chorioamnionitis, wound complications, postpartum hemorrhage, and thrombosis did not increase over time.

CONCLUSION

Women should be counseled regarding the duration of the second stage of labor, which should include a discussion of the risks associated with a cesarean delivery with a prolonged second stage of labor. However, these risks may not be as high as anticipated.

Efficacy of transvaginal cervical cerclage in women at risk of preterm birth following previous emergency cesarean section

INTRODUCTION

Emergency cesarean sections (EMCS) are associated with subsequent preterm birth, particularly at full dilation (FDCS), which is a cause of both second trimester miscarriages and early, recurrent spontaneous preterm birth (sPTB). The optimal management for these women in subsequent pregnancies is currently unknown. This study aims to assess efficacy of transvaginal cervical cerclage (TVC) in prevention of preterm birth among women who have had an EMCS followed by a subsequent late miscarriage or sPTB.

MATERIAL AND METHODS

A historical cohort study was performed assessing outcomes of women attending the Preterm Surveillance Clinic at St Thomas' Hospital, London, who received TVC, with a history of EMCS (pregnancy A) followed by a sPTB/late miscarriage (pregnancy B) and a subsequent pregnancy (pregnancy C). A historical reference group managed in the same clinic was identified comprising women with any risk factor for sPTB, who required TVC. Incidence of delivery >24 to <30 weeks' gestation was compared with relative risk and 95% confidence intervals (CI). Subgroup analysis was carried out assessing women who had a previous FDCS.

RESULTS

209 women with a previous EMCS during labor (50 with FDCS), followed by sPTB/late miscarriage were identified. 178 progressed beyond 24 weeks; of these, 56 received TVC and formed the study group. 905 high-risk women were identified; of these, 154 received TVC and formed the reference group. Despite TVC treatment, 17/56 (30%) of the study group delivered <30 weeks' gestation compared with 5/154 (3%) of the reference group (RR 9.4, 95% CI 3.6-24.2, P < .001). In the subset of 17 women in the study group with a previous FDCS, followed by sPTB/late miscarriage, 6/17 (35%) delivered <30 weeks' gestation, significantly higher than the reference group (P < .001) but similar to EMCS at less than full dilation (35% vs 28%, P = .596). Overall, 33/72 (46%) women receiving cerclage with prior EMCS had either a mid-trimester loss or delivery <30 weeks.

CONCLUSIONS

Transvaginal cervical cerclage appears less effective in preventing preterm birth among pregnant women who have had an EMCS followed by a sPTB/late miscarriage compared with other high-risk women. The lack of efficacy in the subgroup with an FDCS was similar.

Fetal extraction maneuvers during cesarean delivery in the second stage of labor

Objective: To compare maternal and neonatal outcomes following cesarean delivery during second stage of labor, according to the fetal extraction method.Methods: A retrospective cohort study of all women who underwent term cesarean delivery during the second stage of labor at a university-affiliated tertiary medical center (2012-2016). The cohort was divided according to three extraction methods: standard vertex extraction, the push method in which the head extraction is accompanied by pushing through the vagina, and the reverse breech extraction method. Primary outcomes were intraoperative maternal complications, and secondary outcomes were neonatal adverse events.Results: Three hundred and fifty women were included, of whom 206 (59%) underwent standard vertex fetal extraction, 116 (33%) the push method extraction, and 28 (8%) reverse breech extraction. Operation time was significantly shorter in the standard vertex extraction method compared to push and reverse breech extraction methods (33.5 vs. 40.5 and 39.0 min, respectively, p = .013). Uterine laceration and incision extension frequencies were lower in the vertex extraction method as well (24.76 vs. 45.69-46.40% in others, p < .001). Delivery related neonatal injury was significantly more frequent in the reverse breech extraction method (39.29 vs. 12-15% in others, p < .001). In a multivariate analysis reverse breech extraction was associated with higher rates of uterine laceration and incision extension (OR = 2.739 95% confidence interval 1.44-6.56, p = .0237) and delivery related neonatal injury (OR = 2.837, 95% CI: 1.081-7.448, p = .0342).Conclusion: Standard vertex extraction method during second stage of labor cesarean delivery is safer both to the mother and neonate when compared to alternative extraction methods.Abbreviations: NRFHR: non-reassuring fetal heart rate; NICU: neonatal intensive care unit.

Comparison of outcomes at full-dilation cesarean section with and without the use of a fetal pillow device

OBJECTIVE

To identify whether use of the fetal pillow device resulted in a reduction in intraoperative complications, such as uterine incision extension, requirement for breech extraction, etc. Other maternal outcomes (duration of hospital stay, requirement for blood transfusion, and requirement for return to hospital or operating theatre) were also reviewed. Neonatal outcomes of APGAR-5, arterial pH, and requirement for intensive care admission were assessed.

METHODS

A retrospective cohort analysis was completed for fully dilated cesarean deliveries completed between January 2014 and December 2018 at Ipswich Hospital, Australia. In total, 174 patient records were identified (114 with pillow, 60 without). Logistic and linear regressions were used to assess the outcomes associated with fetal pillow use.

RESULTS

There were no significant differences in operative complications between the pillow and no-pillow groups (odds ratio [OR] 0.56, 95% confidence interval [CI] 0.26-1.22, P=0.146). Linear regression analysis showed a decrease in hospital length of stay (hours) (-9.4, 95% CI -17.80 to -0.99, P=0.029) and a higher neonatal arterial pH at delivery (0.06, 95% CI 0.03-0.09, P=0.0001) in the pillow group.

CONCLUSION

At full dilation cesarean, operative complications are not increased when employing the fetal pillow with maternal benefits of decreased hospitalization.

General methods for measuring and comparing medical interventions in childbirth: a framework

Background

The continue increase of interventions during labour in low risk population is a controversial issue of the current obstetric literature, given the lack of evidence demonstrating the benefits of unnecessary interventions for women or infants’ health. This makes it important to have approaches to assess the burden of all medical interventions performed.

Methods

Exploiting the nature of childbirth intervention as a staged process, we proposed graphic representations allowing to generate alternative formulas for the simplest measures of the intervention intensity namely, the overall and type-specific treatment ratios. We applied the approach to quantify the change in interventions following a protocol termed Comprehensive Management (CM), using data from Robson classification, collected in a prospective longitudinal cohort study carried out at the Obstetric Unit of the Cà Granda Niguarda Hospital in Milan, Italy.

Results

Following CM a substantial reduction was observed in the Overall Treatment Ratio, as well as in the ratios for augmentation (amniotomy and synthetic oxytocin use) and for caesarean section ratio, without any increase in neonatal and maternal adverse outcomes. The key component of this reduction was the dramatic decline in the proportion of women progressing to augmentation, which resulted not only the most practiced intervention, but also the main door towards further treatments.

Conclusions

The proposed framework, once combined with Robson Classification, provides useful tools to make medical interventions performed during childbirth quantitatively measurable and comparable. The framework allowed to identifying the key components of interventions reduction following CM. In its turn, CM proved useful to reduce the number of medical interventions carried out during childbirth, without worsening neonatal and maternal outcomes.

Unplanned Cesarean Delivery in the Second Stage of Labor Holds Higher Odds of Complications than in the First Stage, while Similar in Primiparas and Multiparas

BACKGROUND

While endeavors to reduce cesarean delivery (CD) rates are given priority worldwide, it is important to evaluate if these efforts place parturients and neonates at risk. CD performed in the second stage of labor carries higher risks of maternal and fetal complications and is a more challenging surgical procedure than that performed in the first stage or before labor. In a population with a low CD rate, we sought to evaluate the rate of maternal and fetal complications associated with unplanned CD (UCD) performed in the second vs. the first stage of labor, in primiparas and multiparas, as well as the risk factors leading to and the complications associated with UCD in the second stage of labor in this low-CD rate setting.

METHODS

This was a retrospective, electronic medical record-based study of 7,635 term and preterm singletons born via UCD in the period 2003-2015. Maternal and neonatal background and outcome parameters were compared between groups. Logistic regression modeling was applied to adjust for clinically and statistically significant risk factors.

RESULTS

UCD was more likely to be performed in the second stage of labor in mothers delivering larger fetuses (head circumference and body weight ≥90 centile) and those with persistent occiput posterior (POP) presentation. UCD in the second stage was strongly associated with serious maternal complications (excessive hemorrhage and fever) compared to UCD performed in the first stage, in both primiparas and multiparas.

CONCLUSIONS

UCD performed in the second stage of labor, while less frequent than first-stage UCD, is more likely with larger neonates and POP presentation, and is associated with a higher rate of maternal complications in primiparas and multiparas. Complication rates in our low-CD-rate population did not exceed those reported in the literature from high-CD-rate areas.

Comparison of maternal and perinatal morbidity between elective and emergency caesarean section in singleton-term breech presentation

The objective of the study was to compare maternal and neonatal adverse outcomes between elective caesarean section (ElCS) and emergency caesarean section (EmCS) for singleton-term breech presentation. This study included women with singleton breech presentation who underwent ElCS or EmCS at term during 2007-2015 at Siriraj Hospital (Thailand). Complete data were collected for 2178 pregnant women. Of those, 1322 (60.7%) women underwent EmCS, and 856 (39.3%) delivered by ElCS. Maternal and perinatal morbidity were compared. There was no maternal or perinatal death in either group. Maternal morbidity was comparable between groups, except for longer hospital stay in the EmCS group (p = .047). One-minute Apgar score was significantly lower in the EmCS group (p = .040). There was no significant difference in 5-min Apgar score between groups. No significant difference was observed for serious maternal and neonatal morbidity between women who underwent ElCS versus those who underwent EmCS for singleton-term breech presentation.IMPACT STATEMENTWhat is already known on this subject? Emergency caesarean section (EmCS) is generally known to be associated with a higher risk of maternal and neonatal complications than elective caesarean section (ElCS).What do the results of this study add? In singleton-term breech presentation, EmCS in tertiary care setting was not associated with an increase in serious maternal and neonatal morbidity compared with EICS. Cord prolapse as an indication for emergency caesarean section was significantly associated with adverse outcomes while advanced cervical dilation ≥7 cm or low foetal station ≥+1 did not have an impact on maternal and neonatal complications.What are the implications of these findings for clinical practice and/or further research? Mean gestational age in both the ElCS and EmCS groups was approximately 38 weeks and 5 d; there were no neonatal cases with respiratory distress syndrome. Our findings suggest further prospective study in planned caesarean section scheduled for 38-39 weeks in patients with term breech presentation. The results of such a study could yield lower rates of both EmCS and potential adverse outcomes.

Maternal and perinatal mortality and complications associated with caesarean section in low-income and middle-income countries: a systematic review and meta-analysis

BACKGROUND

Universal and timely access to a caesarean section is a key requirement for safe childbirth. We identified the burden of maternal and perinatal mortality and morbidity, and the risk factors following caesarean sections in low-income and middle-income countries (LMICs).

METHODS

For this systematic review and meta-analysis, we searched electronic databases including MEDLINE and Embase (from Jan 1, 1990, to Nov 20, 2017), without language restrictions, for studies on maternal or perinatal outcomes following caesarean sections in LMICs. We excluded studies in high-income countries, those involving non-pregnant women, case reports, and studies published before 1990. Two reviewers undertook the study selection, quality assessment, and data extraction independently. The main outcome being assessed was prevalence of maternal mortality in women undergoing caesarean sections in LMICs. We used a random effects model to synthesise the rate data, and reported the association between risk factors and outcomes using odds ratios with 95% CIs. The study protocol has been registered with PROSPERO, number CRD42015029191.

FINDINGS

We included 196 studies from 67 LMICs. The risk of maternal death in women who had a caesarean section (116 studies, 2 933 457 caesarean sections) was 7·6 per 1000 procedures (95% CI 6·6-8·6, τ²=0·81); the highest burden was in sub-Saharan Africa (10·9 per 1000; 9·5-12·5, τ²=0·81). A quarter of all women who died in LMICs (72 studies, 27 651 deaths) had undergone a caesarean section (23·8%, 95% CI 21·0-26·7; τ²=0·62).

INTERPRETATION

Maternal deaths and perinatal deaths following caesarean sections are disproportionately high in LMICs. The timing and urgency of caesarean section pose major risks.

FUNDING

Ammalife Charity and ELLY Appeal, Barts Charity, and the UK National Institute for Health Research.

Fetal head circumference and subpubic angle are independent risk factors for unplanned cesarean and operative delivery

INTRODUCTION

The aim of this study was to ascertain whether combined ultrasound assessment of fetal head circumference (HC) and maternal subpubic angle (SPA) prior to the onset of labor may predict the likelihood of an unplanned operative delivery (UOD) in nulliparous women at term.

MATERIAL AND METHODS

Prospective cohort study of singleton pregnancies in cephalic presentation. Pregnancies experiencing UOD secondary to fetal distress were excluded. HC was assessed transabdominally and SPA values were obtained from a reconstructed coronal plane on three-dimensional (3D) ultrasound performed translabially at 36-38 weeks of gestation. Maternal characteristics, HC expressed as multiple of median, and SPA were compared according to the mode of delivery. Logistic regression and receiver operating characteristics curve analyses were used to analyze the data.

RESULTS

597 pregnancies were included in the study. Spontaneous vaginal delivery occurred in 70.2% of the cases and UOD was required in 29.8%. There was no difference in pregnancy characteristics and birthweight between women who had a spontaneous vaginal birth compared with UOD. The HC multiple of median was larger (1.00 ± 0.02 vs. 1.03 ± 0.02, p ≤ 0.0001), whereas SPA was narrower in the UOD group (124.02 ± 13.64 vs. 102.61 ± 16.13, p ≤ 0.0001). At logistic regression, SPA (OR 0.91, 95% CI 0.89-0.93), HC multiple of median (OR 1.13, 95% CI 1.09-1.17) and maternal height (OR 0.95, 95% CI 0.92-0.99) were independently associated with UOD. When combined, the diagnostic accuracy of a predictive model integrating HC, SPA and maternal height was highly predictive of UOD with an area under the curve of 0.904 (95% CI 0.88-0.93).

CONCLUSIONS

Ultrasound assessment of fetal HC and maternal SPA after 36 weeks of gestation can identify a subset of women at higher risk of UOD during labor, for whom early planned delivery might be beneficial.