Incidence of shoulder dystocia and risk factors for recurrence in the subsequent pregnancy-A historical register-based cohort study

INTRODUCTION

Shoulder dystocia is a rare obstetric complication, and the risk of recurrence is important for planning future deliveries.

MATERIAL AND METHODS

The objectives of our study were to estimate the incidence and risk factors for recurrence of shoulder dystocia and to identify women at high risk of recurrence in a subsequent vaginal delivery. The study design was a nationwide register-based study including data from the Danish Medical Birth Registry and National Patient Register in the period 2007-2017. Nulliparous women with a singleton fetus in cephalic presentation were included for analysis of risk factors in index and subsequent delivery.

RESULTS

During the study period, 6002 cases of shoulder dystocia were reported with an overall incidence among women with vaginal delivery of 1.2%. Among 222 225 nulliparous women with vaginal births, shoulder dystocia complicated 2209 (1.0%) deliveries. A subsequent birth was registered in 1106 (50.1%) of the women with shoulder dystocia in index delivery of which 837 (77.8%) delivered vaginally. Recurrence of shoulder dystocia was reported in 60 (7.2%) with a six-fold increased risk compared with women without a prior history of shoulder dystocia (risk ratio [RR] 5.70, 95% confidence interval [CI]: 4.41 to 7.38; adjusted RR 3.06, 95% CI: 2.03 to 4.68). Low maternal height was a significant risk factor for recurrence of shoulder dystocia. In the subsequent delivery, significant risk factors for recurrence were birthweight >4000 g, positive fetal weight difference exceeding 250 g from index to subsequent delivery, stimulation with oxytocin and operative vaginal delivery. In the subsequent pregnancy following shoulder dystocia, women who underwent a planned cesarean (n = 176) were characterized by more advanced age and a higher prevalence of diabetes in the subsequent pregnancy. Furthermore, they had more often experienced operative vaginal delivery, severe perineal lacerations, and severe neonatal complications at the index delivery.

CONCLUSIONS

The incidence of shoulder dystocia among nulliparous women with vaginal delivery was 1.0% with a 7.2% risk of recurrence in a population where about 50% had a subsequent birth and of these 78% had subsequent vaginal delivery. Important risk factors for recurrence were low maternal height, increase of birthweight ≥250 g from index to subsequent delivery and operative vaginal delivery.

Levator muscle avulsion and subsequent vaginal delivery: longitudinal 8-year follow-up

OBJECTIVES

The aim of this study is to assess the evolution of levator avulsion from 1 year to 8 years after first delivery in women with subsequent vaginal deliveries compared to women without subsequent vaginal deliveries. Further, we aim to assess whether women with full and partial avulsion 8 years after first delivery have larger levator hiatus area and more symptoms of pelvic organ prolapse compared to women with normal levator insertion.

METHODS

In this single center longitudinal study 195 initially primiparous women were included and underwent transperineal ultrasound 1 year and 8 years after first delivery. Muscle insertion was assessed by tomographic ultrasound imaging in the axial plane. Full levator avulsion was defined as abnormal muscle insertion in all three central slices. Partial levator avulsion was defined as abnormal muscle insertion in one but less than three central slices. Eight years after first delivery levator hiatus area was assessed at rest, during maximum pelvic floor muscle contraction, and maximum Valsalva maneuver. To assess symptoms of pelvic organ prolapse the vaginal symptoms module from the International Consultation on Incontinence Questionnaire was used.

RESULTS

At 1 year follow-up, 25 women (12.8%) showed signs of avulsion, 20 women fulfilled sonographic criteria for full avulsion and 5 women fulfilled sonographic criteria for partial avulsion. Eight years after first delivery, 35 (17.9%) women were diagnosed with avulsion, of them 25 women were diagnosed with full avulsion and 10 women were diagnosed with partial avulsion. No women with partial and full avulsion at 1 year improved on their avulsion status at 8-year follow-up. In the subsequent vaginal delivery group, 21 women (14%) were diagnosed with partial and full levator avulsion 1 year after first delivery, and 31 women (20.7%) were diagnosed with partial and full avulsion 8 years after first delivery. Of the 45 women without subsequent vaginal delivery, one woman with partial avulsion 1 year after first delivery was diagnosed as full avulsion at 8-year follow-up. All women with full avulsion at 1-year follow-up were diagnosed as full avulsion at 8 years regardless of subsequent vaginal delivery. At 8-year follow-up women with full avulsion had statistically significant larger levator hiatus area compared to women with normal muscle insertion. Vaginal symptoms scores ranged between 5.5 (SD 5.7) and 6.0 (SD 4.0) and vaginal symptom quality of life scores ranged between 0.9 (SD 1.4) and 1.5 (SD 2.2) and did not differ statistically significantly between women with normal muscle insertion and women with partial and full avulsion at 8-year follow-up.

CONCLUSION

More avulsions 8 years after first delivery compared to one year after first delivery were found in women with subsequent vaginal delivery. Except one primipara, none of the women without subsequent vaginal delivery changed on their levator status from 1 to 8 years after first delivery. Larger levator hiatus area was found in women with full avulsion compared to women with normal muscle insertion at 8-year follow-up. Vaginal symptoms scores were low and did not differ between women with normal muscle insertion, partial and full avulsion at 8-year follow-up. This article is protected by copyright. All rights reserved.

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.

The association between episiotomy or OASIS at vacuum extraction in nulliparous women and subsequent prelabor cesarean delivery: A nationwide observational study

INTRODUCTION

Severe perineal injuries at childbirth affect women's postnatal health, including future childbirths. First births with vacuum extraction carry an increased risk of obstetric anal sphincter injuries (OASIS). Lateral or mediolateral episiotomy at vacuum extraction may decrease the risk of OASIS. Our aim was to assess whether lateral or mediolateral episiotomy, or OASIS, at vacuum extraction in nulliparous women is associated with prelabor cesarean delivery in the subsequent childbirth.

MATERIAL AND METHODS

This is a nationwide observational study using data from the Swedish Medical Birth Register, including women having a first birth with vacuum extraction and a second birth in 2000-2014. Both births were live, single, cephalic, ≥34 gestational weeks without malformations. The association between episiotomy or OASIS in the first birth and prelabor cesarean delivery in the second birth was examined using univariate and multivariate logistic regression with inverse probability of treatment weighting, and interaction analysis. Main outcome measure was prelabor cesarean delivery in the second birth.

RESULTS

In total, 44 656 women with vacuum extraction at their first birth were included. The rate of prelabor cesarean delivery in the second birth was 5.9% (824 of 13 950) in women with episiotomy, compared with 6.0% (1830 of 30 706) in women without episiotomy. Thus, women with episiotomy did not have an increased risk of prelabor cesarean delivery (adjusted odds ratio [aOR] 1.00, 95% confidence interval [95% CI] 0.83-1.20) compared with women without episiotomy. For comparison, the rate of prelabor cesarean delivery in the second birth was 20.6% (1275 of 6176) in women with OASIS, compared with 3.6% (1379 of 38 480) in women without OASIS (aOR 6.57, 95% CI 5.97-7.23). There was no interaction between episiotomy and OASIS.

CONCLUSIONS

Lateral or mediolateral episiotomy at vacuum extraction in nulliparous women did not increase the risk of prelabor cesarean delivery in the subsequent childbirth. OASIS increased the odds of prelabor cesarean delivery more than sixfold.

Term cesarean delivery in the first pregnancy is not associated with an increased risk for preterm delivery in the subsequent pregnancy

BACKGROUND

Prior studies have reported an increased risk for preterm delivery following a term cesarean delivery. However, these studies did not adjust for high-risk conditions related to the first cesarean delivery and are known to recur.

OBJECTIVE

The objective of the study was to determine whether there is an association between term cesarean delivery in the first pregnancy and subsequent spontaneous or indicated preterm delivery.

STUDY DESIGN

This was a retrospective cohort study of women with the first 2 consecutive singleton deliveries (2007-2014) identified through a linked pregnancy database at a single institution. Women with a first pregnancy that resulted in cesarean delivery at term were compared with women whose first pregnancy resulted in a vaginal delivery at term. Exclusion criteria were known to recur medical or obstetrical complications during the first pregnancy. A propensity score analysis was performed by matching women who underwent a cesarean delivery with those who underwent a vaginal delivery in the first pregnancy. The association between cesarean delivery in the first pregnancy and preterm delivery in the second pregnancy in this matched set was examined using conditional logistic regression. The primary outcome was overall preterm delivery <37 weeks in the second pregnancy. Secondary outcomes included type of preterm delivery (spontaneous vs indicated), late preterm delivery (34-36 6/7 weeks), early preterm delivery (<34 weeks), and small-for-gestational-age birth.

RESULTS

Of a total of 6456 linked pregnancies, 2284 deliveries were matched; 1142 were preceded by cesarean delivery and 1142 were preceded by vaginal delivery. The main indications for cesarean delivery in the first pregnancy were dystocia in 703 (61.5%), nonreassuring fetal status in 222 (19.4%), breech presentation in 100 (8.8%), and other in 84 (7.4%). The mean (SD) gestational ages at delivery for the second pregnancy was 38.8 (1.8) and 38.9 (1.7) weeks, respectively, for prior cesarean delivery and vaginal delivery. The risks of preterm delivery in the second pregnancy among women with a previous cesarean and vaginal delivery were 6.0% and 5.2%, respectively (adjusted odds ratio, 1.46, 95% confidence interval, [CI] 0.77-2.76). In an analysis stratified by the type of preterm delivery in the second pregnancy, no associations were seen between cesarean delivery in the first pregnancy and spontaneous preterm delivery (4.6% vs 3.9%; adjusted odds ratio, 1.40, 95% confidence interval, 0.59-3.32) or indicated preterm delivery (1.6% vs 1.4%; adjusted odds ratio, 1.21, 95% confidence interval, 0.60-2.46). Similarly, no significant differences were found in late preterm delivery (4.6% vs 4.1%; adjusted odds ratio, 1.13, 95% confidence interval, 0.55-2.29), early preterm delivery (1.6% vs 1.2%; adjusted odds ratio, 1.25, 95% confidence interval, 0.59-2.67), or neonates with birthweight less than the fifth percentile for gestational age (3.6% vs 2.2%; adjusted odds ratio, 1.26, 95% confidence interval, 0.52-3.06).

CONCLUSION

After robust adjustment for confounders through a propensity score analysis related to the indication for the first cesarean delivery at term, cesarean delivery is not associated with an increase in preterm delivery, spontaneous or indicated, in the subsequent pregnancy.

Recurrence risk of low Apgar score among term singletons: a population-based cohort study

OBJECTIVE

To examine the risk of recurrence of low Apgar score in a subsequent term singleton pregnancy.

DESIGN

Population-based cohort study.

SETTING

The Netherlands.

POPULATION

A total of 190,725 women with two subsequent singleton term live births between 1999 and 2007.

METHODS

We calculated the recurrence risk of low Apgar score after adjustment for possible confounders. Women with an elective cesarean delivery, fetus in breech presentation or a fetus with congenital anomalies were excluded. Results were reported separately for women with a vaginal delivery or a cesarean delivery at first pregnancy.

MAIN OUTCOME MEASURES

Prevalence of birth asphyxia, a 5-min Apgar score <7.

RESULTS

The risk for an Apgar score of <7 in the first pregnancy was 0.99% and overall halved in the subsequent pregnancies (0.50%). For those with asphyxia in the first pregnancy, the risk of recurrence of a low Apgar score in the subsequent pregnancy was 1.1% (odds ratio 2.1, 95% confidence interval 1.4-3.3). This recurrence risk was present in women with a previous vaginal delivery (odds ratio 2.1, 95% confidence interval 1.2-3.5) and in women with a previous cesarean delivery (odds ratio 3.8, 95% confidence interval 1.7-8.5). Among women with a small-for-gestational-age infant in the subsequent pregnancy and a previous vaginal delivery, the recurrence risk was 4.8% (adjusted odds ratio 5.8, 95% confidence interval 2.0-16.5).

CONCLUSION

Women with birth asphyxia of the first born have twice the risk of renewed asphyxia at the next birth compared to women without birth asphyxia of the first born. This should be incorporated in the risk assessment of pregnant women.

Anal incontinence in women with recurrent obstetric anal sphincter rupture: a case control study

OBJECTIVES

To determine the risk of recurrent anal sphincter rupture (ASR), and compare the risk of anal incontinence (AI) after recurrent ASR, with that seen in women with previous ASR who deliver by caesarean section or vaginally without sustaining a recurrent ASR.

METHODS

Women with recurrent ASR between January 2000 and June 2011 were identified at two delivery wards in Copenhagen. The women answered a questionnaire with a validated scoring system for AI (St. Mark`s score), and the results were compared with those obtained in two control groups: women with subsequent uncomplicated vaginal delivery or caesarean section.

RESULTS

There were 93 437 vaginal deliveries. ASR occurred in 5.5% (n = 2851) of the nulliparous and 1.5% (n = 608) of the multiparous women. Recurrent ASR occurred in 8% (n = 49) of whom 50% reported symptoms of AI. We found no difference in the occurrence of AI between women with recurrent ASR, and those who delivered vaginally without repeat ASR (p = 0.37; OR = 2.0) or by caesarean section (p = 0.77; OR = 1.3).

CONCLUSION

Women with a past history of ASR have an 8% risk of recurrence. AI affects half of the women with recurrent ASR. Larger studies are required to confirm our findings.