Unintended hysterotomy extension during caesarean delivery: risk factors and maternal morbidity

Analysis of Hysterotomy Extension at Unscheduled Cesarean Delivery

This study aimed to determine if the rate of hysterotomy extensions increases with increasing cervical dilation in unscheduled cesarean deliveries, and to develop a measure of the severity of hysterotomy extension for quantifying morbidity.This is a retrospective study of unscheduled cesarean deliveries relating to labor dystocia and/or nonreassuring tracings from January 1, 2021, to December 31, 2021. Severe extension was defined as bilateral or adjacent to a structure such as the uterine artery, broad ligament, or cervix, and was compared with uterine artery extensions alone.There were 990 unscheduled cesarean deliveries included. Extensions (n = 233) significantly increased with increasing cervical dilation (p < 0.0001), complicating more than 30 and 50% at 6 and 10 cm of cervical dilation, respectively. Apart from this trend, a logistic regression analysis indicated cervical dilation was an independent risk factor for extension. Transfusions of at least 2 units of blood were five times (26 vs. 5%) more likely for patients with severe extensions than no extension (p < 0.0001).Hysterotomy extensions significantly increase with increasing cervical dilation, and cervical dilation is an independent risk factor for extension. A composite measure of severity accounts for different types of extension when quantifying morbidity, but uterine artery extension is the primary driver of maternal morbidity in cases without hysterectomy. · We report higher than previously published rates of extension, in our study of unscheduled cesareans.. · Extension rates rise with cervical dilation-33% at 6 cm, over 50% at 10 cm.. · Cervical dilation is an independent risk factor for extension.. · Severe extensions were fivefold more likely to be transfused two units than no extension.. · The composite measure for severity was driven by uterine artery extensions..

Unintended Upper Uterine Wall Extensions at the Time of Cesarean Delivery: Risk Factors and Associated Adverse Maternal and Neonatal Outcomes

This study aims to estimate the frequency of unintended upper uterine wall extensions during cesarean delivery (CD) and identify associated risk factors and adverse outcomes.A multicenter retrospective cohort study was conducted, including patients who underwent CD between 2005 and 2021. Demographic factors, obstetric history, CD indications, delivery and surgical characteristics, adverse maternal and neonatal outcomes were compared between those with unintended upper uterine wall extensions during CD and those without extensions. Crude and adjusted estimates (odds ratios [ORs] and 95% confidence intervals [CIs]) were used.Among 30,517 patients meeting inclusion criteria, 117 (0.4%) had an unintended upper uterine wall extension. In univariate analysis, upper uterine wall extensions were associated with higher rates of intrapartum CD, second-stage CD, unplanned or emergency CD, CD following failed vacuum delivery or trial of labor after CD, chorioamnionitis, prolonged labor, increased vaginal exams, lower fetal head station, and higher birth weight. During surgery, higher rates of general anesthesia, significant intraperitoneal adhesion, fetal malpresentation, and fetal extraction by the leg were observed. Multivariable analysis identified fetal extraction not by head (adjusted OR [aOR]: 9.17, 95% CI: 5.35-15.73), vertex fetal presentation (aOR: 3.65, 95% CI: 1.81-7.35), second-stage CD (aOR: 3.07, 95% CI: 1.24-7.59), and trial of labor after cesarean (aOR: 2.04, 95% CI: 1.08-3.84) as significant risk factors for unintended upper uterine wall extensions. Additionally, upper uterine wall extensions were associated with higher rates of maternal and neonatal complications, including longer operating times, excessive bleeding, postpartum hemorrhage, intraperitoneal drainage, blood product transfusion, puerperal fever, paralytic ileus, Apgar score < 7 at 1 and 5 minutes, and fetal intracranial hemorrhage.Our study identifies risk factors for unintended upper uterine wall extensions during CD. While these extensions are infrequent, their occurrence is associated with increased maternal and neonatal morbidity. · Unintended upper uterine wall extensions occur in 0.4% of cesarean deliveries.. · Significant risk factors include fetal extraction not by head and second-stage CD.. · Extensions are associated with increased maternal complications like excessive bleeding and prolonged surgery.. · Neonatal complications include lower Apgar scores and intracranial hemorrhage.. · Awareness of these risks is critical for improving cesarean delivery outcomes..

Obstetrician views on Fetal Pillow® device use and research in Aotearoa New Zealand: A cross-sectional survey

BACKGROUND

There is anecdotal evidence of Fetal Pillow® use, but no formal local information on clinician practices and perspectives.

AIMS

To assess obstetrician use of the Fetal Pillow®, knowledge of relevant research, and interest in a proposed randomised controlled trial in Aotearoa New Zealand.

MATERIALS AND METHODS

Anonymous cross-sectional survey of practising obstetricians and obstetric trainees in Aotearoa New Zealand distributed by the Royal Australian and New Zealand College of Obstetricians and Gynaecologists.

RESULTS

Of 136 respondents (69% specialists and 31% trainees), 130 had heard of the Fetal Pillow® device, and 108 had used it at least once (43% more than ten times). The device was available in 17/21 units represented. The 108 users of the device reported this was most commonly on collegial advice (63%) or after personal experience of a difficult delivery (33%) and most (80%) believed it reduced maternal morbidity. Only around one-third of the 130 respondents who had heard of the device agreed there was adequate research demonstrating its efficacy for maternal (36%) and neonatal (30%) morbidity. The majority reported they would change practice in response to a randomised trial, although they were more likely to start use (81% of current non-users) than stop (53% of users). Most (70%) respondents agreed they would encourage patients to participate in a randomised trial.

CONCLUSIONS

The Fetal Pillow® is available in most maternity units in Aotearoa New Zealand. The majority of obstetric clinicians believe it reduces maternal morbidity, while acknowledging the lack of scientific evidence. Most would support a randomised trial.

Accidental uterine extensions in cesarean deliveries - outcome of subsequent pregnancy

OBJECTIVES

To explore the obstetric, maternal and neonatal outcome in the subsequent pregnancy after a pregnancy with an accidental uterine extension (AUE) during cesarean delivery (CD), as well as the relationship between the different types of AUE (inferior, lateral and superior).

METHODS

A retrospective cohort study of all CD with AUE in a tertiary medical center between 01/2011-01/2022. Women with a prior CD with AUE were compared to a 1:3 ratio matched control group of women with a prior CD without AUE. All AUE were defined in their direction, size and mode of suturing. CD with deliberate uterine extensions were excluded. We evaluated obstetric, maternal and neonatal outcomes in the subsequent pregnancy after a pregnancy with AUE during CD.

RESULTS

Comparing women with a prior CD with AUE (n=177) to the matched control group of women with a prior CD without AUE (n=528), we found no significant differences in proportions of uterine rupture or any other major complication or adverse outcome between the groups. There were no significant differences in the outcomes of the subsequent pregnancy in relation to the characteristics of the AUE (direction, size and mode of suturing).

CONCLUSIONS

Subsequent pregnancies after AUE are not associated with higher maternal or neonatal adverse outcomes including higher proportions of uterine rupture compared to pregnancies without previous AUE. Different characteristics of the AUE do not impact the outcome.

Maternal and neonatal morbidity associated with Fetal Pillow® use at full dilatation caesarean: A retrospective cohort

OBJECTIVE

To investigate associations of the Fetal Pillow® with maternal and neonatal morbidity.

DESIGN

Retrospective cohort.

SETTING

Two tertiary maternity units, New Zealand.

POPULATION OR SAMPLE

Full dilatation singleton, term, cephalic caesarean section, with three comparisons: at Unit A (1) before versus after introduction of the Fetal Pillow® (1 Jaunary 2016-31 October 2021); (2) with versus without the Fetal Pillow® after introduction (27 July 2017-31 October 2021); and (3) between Unit A and Unit B during the same time period (1 January 2019-31 October 2021). The Fetal Pillow® is unavailable at Unit B.

METHODS

Cases were ascertained and clinical data were extracted from electronic clinical databases and records. Outcome data were adjusted and presented as adjusted odds ratios (aOR) with 95% CI.

MAIN OUTCOME MEASURES

Primary outcome "any" uterine incision extension; secondary outcomes included major extension (into adjacent structures), and a composite neonatal outcome.

RESULTS

In all, 1703 caesareans were included; 375 with the device and 1328 without. Uterine incision extension rates were: at Unit A before versus after introduction: 26.8% versus 24.8% (aOR 0.88, 95% CI 0.65-1.19); at Unit A with the Fetal Pillow® versus without: 26.1% versus 23.8% (aOR 1.14, 95% CI 0.83-1.57); and at Unit A versus Unit B: 24.2% versus 29.2% (aOR 0.73, 95% CI 0.54-0.99). No differences were found in major extensions, or neonatal composite outcome.

CONCLUSIONS

Despite the relatively large size of this study, it could not rule out either a positive or a negative association between use of the Fetal Pillow® and uterine extensions, major uterine incision extensions, and neonatal morbidity. Randomised controlled trial evidence is required to assess efficacy.

The association between unintended hysterotomy extensions with cesarean delivery and subsequent preterm birth

BACKGROUND

An increased risk for preterm birth has been observed among individuals with a previous second stage cesarean delivery when compared with those with a previous vaginal delivery. One mechanism that may contribute to the increased risk for preterm birth following a second stage cesarean delivery is the increased risk for cervical injury because of extension of the uterine incision (hysterotomy) into the cervix. The contribution of hysterotomy extension to the rate of preterm birth in a subsequent pregnancy has not been investigated and may shed light on the mechanism underlying the observed relationship between the mode of delivery and subsequent preterm birth.

OBJECTIVE

We aimed to quantify the association between unintended hysterotomy extension and preterm birth in a subsequent delivery.

STUDY DESIGN

We performed a retrospective cohort study using electronic perinatal data collected from 2 university-affiliated obstetrical centers. The study included patients with a primary cesarean delivery of a term, singleton live birth and a subsequent singleton birth in the same catchment (2005-2021). The primary outcome was subsequent preterm birth <37 weeks' gestation; secondary outcomes included subsequent preterm birth at <34, <32, and <28 weeks' gestation. We assessed crude and adjusted associations between unintended hysterotomy extensions and subsequent preterm birth with log binomial regression models using rate ratios and 95% confidence intervals. Adjusted models included several characteristics of the primary cesarean delivery such as maternal age, length of active labor, indication for cesarean delivery, chorioamnionitis, and maternal comorbidity.

RESULTS

A total 4797 patients met the study inclusion criteria. The overall rate of unintended hysterotomy extension in the primary cesarean delivery was 6.0% and the total rate of preterm birth in the subsequent pregnancy was 4.8%. Patients with an unintended hysterotomy extension were more likely to have a longer duration of active labor, chorioamnionitis, failed vacuum delivery attempt, second stage cesarean delivery, and persistent occiput posterior position of the fetal head in the primary cesarean delivery and higher rates of smoking in the subsequent pregnancy. Multivariable analyses that controlled for several confounders showed that a history of hysterotomy extension was not associated with a higher risk for preterm birth <37 weeks' gestation (adjusted rate ratio, 1.55; 95% confidence interval, 0.98-2.47), but it was associated with preterm birth <34 weeks' gestation (adjusted rate ratio, 2.49; 95% confidence interval, 1.06-5.42).

CONCLUSION

Patients with a uterine incision extension have a 2.5 times higher rate of preterm birth <34 weeks' gestation when compared with patients who did not have this injury. This association was not observed for preterm birth <37 weeks' gestation. Future research should aim to replicate our analyses with incorporation of additional data to minimize the potential for residual confounding.

Unintended uterine extension at the time of cesarean delivery - risk factors and associated adverse maternal and neonatal outcomes

OBJECTIVE

To identify risk factors, maternal and neonatal adverse outcomes related to unintended lower segment uterine extension during cesarean delivery (CD).

METHODS

A retrospective cohort analysis in a single, university-affiliated medical center between 1 January 2018 and 31 December 2019. All singleton pregnancies delivered by CD were included. Univariate and multivariate analyses were performed to identify maternal and obstetrical predictors for uterine extension during CD. For secondary outcomes, we assessed the correlation between uterine extension and any adverse maternal or neonatal outcome. Risk factors were analyzed using ROC statistics to measure their prediction performance for a uterine extension.

RESULTS

Overall, 1746 (19.3%) CDs were performed during the study period. Of them, 121 (6.9%) CDs were complicated by unintended uterine extension. There was no difference in maternal demographics and clinical data stratified by uterine extension at CD. Uterine extensions were significantly more common following induction of labor, intrapartum fever, premature rupture of membranes, a trial of labor after cesarean, advanced gestational age, emergent CD, and in particular CD during the second stage of labor (37.2% vs. 6.5%) and after failed vacuum extraction (6.6% vs. 1.1%), p < .05 for all. The incidence of postpartum hemorrhage and re-laparotomy did not differ between the groups. Most of the extensions were caudal-directed (40.4%), and were closed by a two-layer closure (92%). Mean extension size was 4.5 ± 1.7 cm. Using multivariable analysis, the only factor that remained significant was CD at the second stage of labor (adjusted odds ratio (aOR) 54.2, 95% CI 4.5-648.9, p = .002), with an area under the ROC curve 0.653 (95% CI 0.595-0.712, p < .001). Emergent CD, body mass index, birth weight, failed vacuum attempt, and trial of labor after cesarean were not significant. For secondary outcomes, an unintended uterine extension was associated with longer operation time, higher estimated blood loss, greater pre- to post-CD hemoglobin difference, increased blood products transfusion, puerperal fever, and longer hospital stay. No clinically significant neonatal adverse outcomes were observed.

CONCLUSIONS

In our cohort, second-stage CD was the strongest predictor for an unintended uterine extension. Following uterine extension, women had increased infectious and blood-loss morbidity.

Unintended lower-segment hysterotomy extension at cesarean delivery and the risk for uterine rupture during a subsequent trial of labor

OBJECTIVE

To evaluate the association between unintended uterine extension in cesarean delivery and uterine scar disruption (rupture or dehiscence) at the subsequent trial of labor after cesarean delivery (TOLAC).

METHODS

This is a multicenter retrospective cohort study (2005-2021). Parturients with a singleton pregnancy who had unintended lower-segment uterine extension during the primary cesarean delivery (excluding T and J vertical extensions) were compared with patients who did not have an unintended uterine extension. We assessed the subsequent uterine scar disruption rate following the subsequent TOLAC and the rate of adverse maternal outcome.

RESULTS

During the study period, 7199 patients underwent a trial of labor and were eligible for the study, of whom 1245 (17.3%) had a previous unintended uterine extension and 5954 (82.7%) did not. In univariate analysis, previous unintended uterine extension during the primary cesarean delivery was not significantly associated with uterine scar rupture in the following subsequent TOLAC. Nevertheless, it was associated with uterine scar dehiscence, higher rates of TOLAC failure, and a composite adverse maternal outcome. In multivariate analyses, only the association between previous unintended uterine extension and higher rates of TOLAC failure was confirmed.

CONCLUSION

A history of unintended lower-segment uterine extension is not associated with an increased risk for uterine scar disruption following subsequent TOLAC.

Risk factors for uterine incision extension during cesarean delivery

BACKGROUND

Unintentional extension of uterine incision is a known complication during cesarean delivery estimated to occur in 4-8% of cesarean deliveries. The aim of this study was to examine risk factors associated with unintentional uterine incision extension and to assess which of them are independent risk factors for this condition.

STUDY DESIGN

We conducted a retrospective cohort study at a large public university tertiary referral center between 2003 and 2017. Included were women who underwent cesarean delivery during this time period. Demographic, medical, obstetrical and surgical data were collected. The primary outcome was the presence of uterine incision extension during cesarean delivery. Secondary outcomes included detection of risk factors associated with uterine incision extension. A multivariate analysis was additionally performed to identify general and labor related risk factors for unintentional extension of uterine incision among patients that underwent cesarean delivery during second stage of labor.

RESULTS

During the study period, 25,879 cesarean deliveries performed in our medical center were assessed. Out of them, 731 (2.8%) cases of unintended uterine incision extension were identified. Women in this group had high rates of full cervical dilatation and increased maternal hemorrhage. Assessment of incision extension direction revealed that two-thirds of extensions were lateral, mostly unilateral. Median size of the extension was 2.7 ± 1.2 cm.Independent parameters associated with unintended uterine incision extension included nulliparity, vertex presentation, epidural anesthesia and cesarean section indication. Further analysis including cesarean deliveries performed during the second stage of labor revealed 397 (15.3%) cesarean deliveries in which incision extension was noted and 2205 (84.7%) cesarean deliveries without incision extension. Following multivariate analysis performed in women who underwent cesarean delivery during second stage of labor, two independent parameters associated with unintended uterine incision extension remained significant - past cesarean delivery and failed vacuum attempt.

CONCLUSIONS

Vacuum extraction attempt and previous cesarean delivery are independent risk factors for uterine incision extension in women undergoing cesarean delivery during the second stage of labor. We also showed the majority of these extensions to be lateral.

Is duration of passive second stage associated with a risk of hysterotomy extension during cesarean?

Objective

To assess obstetric factors associated with hysterotomy extension among women undergoing a second-stage cesarean.

Study design

This 5-year retrospective cohort study (2013–2017) included all women with second-stage cesarean deliveries of live-born singleton fetuses in cephalic presentation at term. It took place at a tertiary center that practices delayed pushing. We performed univariable and multivariable logistic regression to assess the maternal, obstetric, and neonatal factors associated with hysterotomy extension mentioned in the surgical report. Operative time, postpartum hemorrhage, and maternal complications were also studied.

Results

Of the 3350 intrapartum cesareans, 2637 were performed at term for singleton fetuses in cephalic presentation: 747 (28.3%) during the second stage of labor, 83 (11.1%) of which were complicated by a hysterotomy extension. The median duration of the passive phase of the second stage did not differ between women with and without an extension (164 min versus 160 min, P = 0.85). No other second-stage obstetric characteristics, i.e., duration of the active phase, fetal head station, or fetal malposition, were associated with the risk of extension. Factors significantly associated with extension were the surgeon’s experience and forceps use during the cesarean. Women with an extension, compared to women without one, had a longer median operative time (49 min versus 32 min, P<0.001) and higher rates of postpartum hemorrhage and blood transfusion (respectively, 30.1% versus 15.1%, p = 0.002 and 7.2% versus 2.4%, P = 0.03).

Conclusion

The risk of a hysterotomy extension does not appear to be associated with second-stage obstetric characteristics, including the duration of the passive phase of this stage. In our center, which practices delayed pushing, prolonging this passive phase beyond 2 hours does not increase the risk of hysterotomy extension in second-stage cesareans.

The impact of prolonged second stage in twins on perinatal outcomes

OBJECTIVE

To assess the duration of the second stage of labor in twin pregnancies in relation to maternal and neonatal outcomes.

METHODS

A retrospective study between 2014 and 2020. Eligible cases were twin pregnancies that reached the second stage. The pre-defined groups were based on the total time spent in the second stage of labor; Group 1 (<1 h), group 2 (1-2 h), and group 3 (>2 h), which was considered the prolonged second stage group.

RESULTS

Among the 439 planned vaginal births, successful vaginal delivery of both twins was achieved in 63.8%. Prolonged second stage was observed in 25.8% (89/345). Nulliparity (odds ratio [OR] 7.72, 95% confidence interval [CI] 4.5-13.4) and use of epidural analgesia (OR 5.45, 95% CI 1.2-24.7), were the only independent variables significantly associated with prolonged second stage. Prolonged second stage was associated with a greater risk of intrapartum cesarean delivery (32.6%, P < 0.001), combined delivery (10.1%, P < 0.001), chorioamnionitis (8.3%, P = 0.006) and a admission to neonatal intensive care unit of at least one of the twins (30.3%, P = 0.02).

CONCLUSION

Prolonged second stage of labor affects maternal and fetal outcome in twin pregnancies.