Is the risk of obstetric anal sphincter injuries increased in vaginal twin deliveries?

Vacuum extraction in twin deliveries-maternal and neonatal consequences: a retrospective cohort study

PURPOSE

To establish the frequency of vacuum extraction among parturients with twin pregnancies, identify the risk factors and perinatal outcomes.

METHODS

A retrospective cohort database study was conducted between 2005-2018. Twin fetuses with vertex presentation >34 weeks gestation who achieved vaginal delivery were included. Outcomes were compared between neonates who were delivered by vacuum extraction and neonates delivered by spontaneous vaginal delivery (aORs; [95% CI]).

RESULTS

A total of 1751 neonates of 905 parturients with twin pregnancies met inclusion criteria, of which 163 (18%) parturients had vacuum extraction and 225 (12.8%) neonates were delivered by vacuum extraction. The most significant risk factors for vacuum extraction were primiparity (6.79 [4.77-9.66]), previous cesarean delivery (5.59 [3.13-9.97]), and epidural analgesia (4.34 [1.83-10.31]). Vacuum extractions were associated with a spectrum of adverse maternal outcomes (2.60 [1.61-4.19]), particularly postpartum hemorrhage and its associated morbidities. From the neonatal aspect, vacuum extraction deliveries were associated with a composite of birth trauma injuries (21.81 [6.43-73.91]).

CONCLUSION

Vacuum extractions among twin pregnancies were found to be associated with significantly higher rates of postpartum hemorrhage, blood transfusion, and perinatal birth trauma. These findings should be presented to women when counseling on mode of delivery and considered individually against cesarean delivery disadvantages.

A novel classification for evaluating episiotomy practices: application to the Burgundy perinatal network

Background

Though the rate of episiotomy has decreased in France, the overall episiotomy rate was 20% in the 2016 national perinatal survey. We aimed to develop a classification to facilitate the analysis of episiotomy practices and to evaluate whether episiotomy is associated with a reduction in the rate of obstetric anal sphincter injuries (OASIS) for each subgroup.

Methods

This population-based study included all the deliveries that occurred in the Burgundy Perinatal Network from 2011 to 2016. The main outcome was episiotomy, which was identified thanks to the French Common Classification of Medical Procedures. An ascending hierarchical cluster analysis was performed to build the classification. A clinical audit using the classification was conducted yearly in all obstetric units. The episiotomy rates were described throughout the study period for each subgroup of the classification. The OASIS rates were evaluated by subgroup and the association between mediolateral episiotomy and OASIS was investigated for each subgroup.

Results

Our analyses included 81,290 pregnant women. The classification comprised 7 subgroups: ₍₁₎ nulliparous single cephalic at term, ₍₂₎ nulliparous single cephalic at term with instrumental delivery, ₍₃₎ multiparous single cephalic at term, ₍₄₎ multiparous single cephalic at term with instrumental delivery, ₍₅₎ all preterm deliveries (< 37 weeks gestation), ₍₆₎ all breech deliveries, ₍₇₎ all multiple deliveries.

Episiotomy rates ranged from 6.2% in Group 3 to 40.9% in Group 2. From 2011 to 2016, every group except breech deliveries experienced a significant decrease in episiotomy rates, ranging from − 28.1 to − 61.0%.

The prevalence of OASIS was the highest in Groups 2 (3.0%) and 4 (2.2%). Overall OASIS rates did not significantly differ with episiotomy use (P = 0.25). However, we found that the use of episiotomy was associated with a reduction in OASIS rates in Groups 1 and 2 (odds ratio 0.6 [95% CI 0.4–0.9] and 0.4 [0.3–0.5], respectively). This reduction was only observed in Group 4 with forceps delivery (odds ratio 0.4 [0.1–0.9]).

Conclusion

We developed the first classification for the evaluation of episiotomy practices based on 7 clinically relevant subgroups. This easy-to-use tool can help obstetricians and midwives improve their practices through self-assessment.

Electronic supplementary material

The online version of this article (10.1186/s12884-019-2424-2) contains supplementary material, which is available to authorized users.

A comparative study of obstetric anal sphincter injuries in vaginal deliveries of twins and singleton pregnancies

AIMS

Increasing numbers of twin pregnancies necessitate investigation of the risk factors associated with obstetric anal sphincter injuries (OASIS). The aims of this study were to establish the incidence of OASIS, and compare women delivering twins to those delivering singletons in risk of OASIS plus maternal, neonatal, and obstetric outcomes.

METHODS

A retrospective cohort study was undertaken and included women delivering in a tertiary London maternity unit between 1999 and 2015; 51 957 eligible women with singleton and 261 with twin pregnancies were identified. Women delivering twins were compared to those delivering singletons in the occurrence of maternal, neonatal, and obstetric outcomes using unadjusted relative risks. A secondary analysis was performed, and conditional logistic regression used to derive an adjusted relative risk of OASIS. Women delivering singletons were matched to those delivering twins for age, parity, ethnicity, gestation, and mode of delivery in a ratio of 2:1.

RESULTS

Compared to the singleton group, mothers delivering twins had significantly more instrumental deliveries (RR [95%CI] 1.92 [1.67-2.27]; P < 0.0001), smaller fetuses (2754.1 vs 3383.8 g; P < 0.001), and were older (32.9 vs 31.0 years; P < 0.0001). The twin group was not significantly different to the singleton group in risk of OASIS (RR 0.61 [0.27-1.33], P = 0.205). The conditional logistic regression demonstrated similar results for the risk of OASIS (adjusted RR = 0.58 [0.22-1.47]; P = 0.253).

CONCLUSIONS

Women delivering twins vaginally were not at a significantly higher risk of sustaining OASIS compared to those delivering singletons.