Neonatal mortality and morbidity in vertex-vertex second twins according to mode of delivery and birth weight

Guideline No. 428: Management of Dichorionic Twin Pregnancies

OBJECTIVE

To review evidence-based recommendations for the management of dichorionic twin pregnancies.

TARGET POPULATION

Pregnant women with a dichorionic twin pregnancy.

BENEFITS, HARMS, AND COSTS

Implementation of the recommendations in this guideline may improve the management of twin pregnancies and reduce neonatal and maternal morbidity and mortality.

EVIDENCE

Published literature was retrieved through searches of PubMed and the Cochrane Library using appropriate controlled vocabulary (e.g., twin, preterm birth). Results were restricted to systematic reviews, randomized controlled trials, controlled clinical trials, and observational studies. There were no date limits, but results were limited to English- or French-language materials.

VALIDATION METHODS

The content and recommendations were drafted and agreed upon by the principal authors. The Board of the SOGC approved the final draft for publication. The authors rated the quality of evidence and strength of recommendations using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. See online Appendix A (Tables A1 for definitions and A2 for interpretations of strong and weak recommendations).

INTENDED AUDIENCE

Obstetricians, family physicians, nurses, midwives, maternal-fetal medicine specialists, radiologists, and other health care providers who care for women with twin pregnancies.

SUMMARY STATEMENTS

RECOMMENDATIONS.

Internal Version Compared With Pushing for Delivery of Cephalic Second Twins

OBJECTIVE

To assess neonatal morbidity and mortality according to whether cephalic second twins were born after internal version followed by total breech extraction or after instructions to push. We hypothesized that interval version would result in shorter intertwin delivery intervals and lower cesarean delivery rates for the second twin and therefore better neonatal outcomes.

METHODS

These planned analyses of the JUMODA (JUmeaux MODe d'Accouchement) cohort, a national prospective population-based study of twin deliveries, examined births of cephalic second twins after vaginal birth of the first twin at or after 32 weeks of gestation. The internal version group of second twins born in breech presentation after obstetric maneuvers was compared with the pushing group, comprising those born in cephalic presentation. The primary outcome was a composite of neonatal morbidity and mortality. Multivariate modified Poisson regression models were used to control for potential confounders.

RESULTS

Of 2,256 cephalic second twins, 487 (21.6%) were born in breech presentation after internal version and total breech extraction and 1,769 (78.4%) in cephalic presentation after pushing. Composite neonatal morbidity and mortality was not lower in the internal version (17/487 [3.5%]) compared with the pushing group (38/1,769 [2.1%]; adjusted relative risk [aRR] 1.73 [95% CI 0.98-3.05]), although median [quartile 1-quartile 3] intertwin delivery intervals were shorter (5 [4-8] vs 8 [5-12] minutes, P<.001) and the cesarean delivery rate for the second twin lower (5/487 [1.0%] vs 66/1,769 [3.7%], P=.002). Subgroup analyses showed no difference between groups at or after 37 weeks of gestation but higher composite neonatal morbidity and mortality after internal version before 37 weeks (14/215 [6.5%] vs 26/841 [3.1%]; aRR 2.18 [95% CI 1.15-4.13]). Secondary analyses according to center expertise in the overall population and stratified by gestational age yielded concordant results.

CONCLUSION

Although our sample size precluded a robust assessment for small differences in outcomes between groups, internal version followed by total breech extraction of cephalic second twins was not associated with better neonatal outcomes than pushing.

Type of delivery and reading, writing, and arithmetic learning in twin births

This study analyses, in children born in twin births, the relationship between reading, writing and arithmetic learning, on the one hand, and type of delivery, on the other, controlling for the effect of interaction and/or confusion of third variables (maternal age at delivery, gestational age, fetal position, birthweight, 1-min Apgar score). In the planned retrospective cohort design, the exposed cohort consisted of children born by caesarean section, and the non-exposed cohort was comprised of children born vaginally. One hundred and twenty-four children born of twin births were evaluated during their first year of primary school: K-BIT tests were used to measure intelligence; the Evalúa-1 battery was used to assess reading, writing, and arithmetic ability; and the children's clinical histories were analysed for obstetric and neonatal variables. After applying binary logistic regressions for each dependent variable, it was found that caesarean delivery in twin births appeared as a possible independent risk factor for specific learning disabilities (LDs) in reading, writing, and arithmetic. Based on these results, further research using larger samples and at more advanced ages is required in order to analyse the influence of obstetric and neonatal variables on the processes underlying specific LDs.

Type of Delivery, Neuropsychological Development and Intelligence in Twin Births

Based on a retrospective cohort design with 6-year-old children born in twin births, the relationship between verbal, non-verbal, global neuropsychological development, general intelligence and type of delivery has been studied. To this end, the possible effect of third gestational, obstetric and neonatal variables, such as maternal age at delivery, fetal presentation, gestational age, newborn weight and Apgar at minute one, was controlled. The exposed cohort includes children born by cesarean section, and the unexposed cohort is composed of children born vaginally with or without induction. A total of 124 children were evaluated in their 1st year of primary school using the Child Neuropsychological Maturity Questionnaire, Kaufman's Intelligence Test and the medical histories of the children collected after birth. By means of binary logistic regression analysis, it has been found that the type of delivery is presented as an independent risk factor for disorders in verbal, non-verbal and global development and for the general intellectual difficulties of children born of multiple births. These results suggest the need to analyze in future prospective studies with broader samples the relationship between different types of obstetric and perinatal variables of birth type and infant neuropsychological development and general intelligence, in order to prevent possible psychological alterations from birth.

The burden to be second twin: a population-based study of 2686 twins: (2124 dichorionic). Proposal of the concept of mobility

Objectives: To identify if there is a specific neonatal morbidity/mortality among second twins relative to first twins.Study design: A 17-year (2001-2017) population-based observational cohort of all twin newborns born in the South of Reunion island after 21 weeks.Results: Among 1062 dichorionic (DTP) and 281 monochorionic twin pregnancies (2686 newborns), twin 2 have a doubled risk to be in breech presentation and a bad Apgar at 1 mn (≤6) in vaginal deliveries. Specific to dichorionic pregnancies, twin 2 were lighter by 50-60 g than twin 1, had higher rates of intrauterine growth retardation (IUGR), OR 1.33, p = .007, a doubled risk to have congenital abnormalities OR 2.1, p = .006.Conclusion: In dichorionic twin pregnancies, second twins having a doubled prevalence of severe congenital abnormalities are not completely elucidated and deserves further research. (1) We propose that twin 2 presenting higher risks of being IUGR and much higher risks of severe malformations suggest that during pregnancy, the less mobile of the two twins is "relegated" to the back of the uterus. (2) For interventions in the delivery room, systematically the most experimented neonatologist should plan to manage the second twin because significantly twin 2 presents higher problems than twin 1.

The Effect of Twin Birth on Neonatal and Infant Mortality Rates: A Systematic Review

Background and aims: Twin birth may account for higher mortality rates in infants and neonates. To investigate the potential relationship between twin birth and infant and neonatal mortality rates (NMRs), a systematic review was conducted. Methods: To gather the evidence for the relationship between twin birth and its potential effect on mortality during infancy and neonatal periods, a systematic review was conducted. The most important used databases were PubMed, Google Scholar, Web of Science, Scopus, ProQuest, Cochrane and Springer. Then, the databases were searched by appropriate keywords. After reviewing and evaluating the collected studies, trends in the different countries were compared. Results: A total of 13 790 related studies were found, of which 128 studies were selected in the first step. The studies which were not related to the subject, in addition to repetitive studies, were excluded from the search in the second step based on inclusion and exclusion criteria by reviewing the abstract and, in some cases, the full article. Finally, 7 studies entered the last step. Conclusion: This study showed that the mortality could be higher among twins than among non-twins, especially among boys.

Neonatal hypoxia of the second twin after vaginal delivery of the first twin: what matters?. J Matern Fetal Neonatal Med 2018. [PMID: 29527962 DOI: 10.1080/14767058.2018.1451510]

Objective: Optimal management of twin deliveries is controversial. We aimed to assess potential risk factors correlated to the development of hypoxia in the second twin after vaginal delivery of the first twin. Study design: This is a retrospective observational study including diamniotic twin pregnancies delivering at our Institution at 35 weeks of gestational age or more, weighing ≥1800 g. Hypoxia was defined as at least one of the following: Apgar score <5 at 10 minute, neonatal resuscitation for >10 minutes, neonatal acidosis (pH ≤7 and/or BE ≥12 mmol/L). Results: A number of 275 diamniotic twin pregnancies met the inclusion criteria and were divided within the following groups: (1) second twin not developing neonatal hypoxia (n = 265); and (2) second twin developing neonatal hypoxia (n = 10). The rate of second twins with neonatal hypoxia during the study period was 3.6% (10/275). Abnormal cardiotocography during the intertwin delivery interval, defined as ACOG category III, was significantly correlated to second twin hypoxia. Of interest, there was no significant difference in the intertwin delivery interval between the study groups. In addition, breech presentation of the second twin did not show to be a risk factor for neonatal hypoxia. None of the second twins developing neonatal hypoxia was reported to have encephalopathy (follow up of at least 24 months). At multivariate analysis, only abnormal cardiotocography was an independent risk factor for second twin hypoxia (OR 17.8, 95% CI 4.1-77.2). Conclusions: In our study, neonatal hypoxia was significantly correlated to abnormal cardiotocography, while intertwin delivery interval was not correlated to the development of this adverse neonatal outcome.

Birth management and fetal outcome in multiple gestation: analysis of 1.444 births

PURPOSE

Since the late 1990s, controversies came up concerning the mode of delivery for multiples births. The twin birth study indicated no difference in maternal and fetal outcome between planned vaginal delivery and planned caesarean section, but did not analyze the influence of maternal and fetal characteristics or the obstetric management in vaginal birth. The purpose of this study is to analyze these parameters regarding fetal outcome.

METHODS

A large-scale retrospective analysis of twin births (n = 1.444) was performed at a university medical center. The analysis included pregnancy, delivery, and maternal and fetal parameters, including pH and base excess (BE) differences between the first- and second-born twin (delta pH, delta BE).

RESULTS

Delta pH correlated significantly with the birth interval for various positions of twins in the womb (p < 0.05). The longer the birth interval, the greater the delta pH with a lower pH of the second twin. Delta BE values were significantly correlated with the birth interval for a combination of twins in cephalic and breech presentation. Furthermore, it could be shown that higher differences in birth weight between the first/second twin are associated with higher delta pH, higher delta BE values (all p < 0.05). We found significantly decreasing delta pH values in vaginal deliveries over secondary and, finally, primary caesarean sections (p < 0.001).

CONCLUSION

We conclude a vaginal delivery of twin appears safe if experienced staff monitor birth weight discrepancies, birth interval, and blood values consequently. A good outcome also for the second twin delivered spontaneously is nevertheless feasible if experienced staff is available.

Perinatal Outcome of the Second Twin at a Tertiary Care Center in India

PURPOSE

This cross-sectional observational study was undertaken to assess perinatal outcome of the second twin in respect to gestational age, presentation, mode of delivery, and birth weight.

METHODS

Seventy women with confirmed twin pregnancy were admitted and managed in a tertiary care teaching hospital in Kolkata, India from May 2008 to April 2009. All relevant data were recorded and analyzed statistically by simple proportions and χ² test.

RESULTS

Women with frequent antenatal visits had highly favorable perinatal outcome than those with fewer or no visits in this hospital (p < 0.001). Higher perinatal mortality was observed among preterm than term (p < 0.01) cases, and among low birth weight than normal babies (p < 0.05). Second twins in vertex-vertex presentation encountered higher perinatal mortality compared to those in vertex-nonvertex and nonvertex-other presentations (p < 0.05). Perinatal outcome was unfavorable when both delivered vaginally than for both cesarean deliveries and cesarean after first vaginal delivery (p < 0.01). Preterm labor was the most frequently observed maternal complication. Birth asphyxia and perinatal mortality were common among second than first twins.

CONCLUSIONS

Gestational age, presentation, mode of delivery, and birth weight are the significant determinants of perinatal outcome of the second twin. Women with frequent antenatal care show favorable outcome. The second twin is at higher risk of perinatal morbidity and mortality than the first twin.

Twin Birth Study: 2-year neurodevelopmental follow-up of the randomized trial of planned cesarean or planned vaginal delivery for twin pregnancy

BACKGROUND

The Twin Birth Study randomized women with uncomplicated pregnancies, between 32(0/7)-38(6/7) weeks' gestation where the first twin was in cephalic presentation, to a policy of either a planned cesarean or planned vaginal delivery. The primary analysis showed that planned cesarean delivery did not increase or decrease the risk of fetal/neonatal death or serious neonatal morbidity as compared with planned vaginal delivery.

OBJECTIVE

This study presents the secondary outcome of death or neurodevelopmental delay at 2 years of age.

STUDY DESIGN

A total of 4603 children from the initial cohort of 5565 fetuses/infants (83%) contributed to the outcome of death or neurodevelopmental delay. Surviving children were screened using the Ages and Stages Questionnaire with abnormal scores validated by a clinical neurodevelopmental assessment. The effect of planned cesarean vs planned vaginal delivery on death or neurodevelopmental delay was quantified using a logistic model to control for stratification variables and using generalized estimating equations to account for the nonindependence of twin births.

RESULTS

Baseline maternal, pregnancy, and infant characteristics were similar. Mean age at assessment was 26 months. There was no significant difference in the outcome of death or neurodevelopmental delay: 5.99% in the planned cesarean vs 5.83% in the planned vaginal delivery group (odds ratio, 1.04; 95% confidence interval, 0.77-1.41; P = .79).

CONCLUSION

A policy of planned cesarean delivery provides no benefit to children at 2 years of age compared with a policy of planned vaginal delivery in uncomplicated twin pregnancies between 32(0/7)-38(6/7)weeks' gestation where the first twin is in cephalic presentation.

Adverse perinatal outcomes related to the delivery mode in women with monochorionic diamniotic twin pregnancies

AIMS

The association between the planned delivery mode and adverse perinatal outcomes of monochorionic diamniotic (MCDA) twin pregnancies at ≥36 weeks' gestation was evaluated.

METHODS

This retrospective cohort study included uncomplicated MCDA twin pregnancies delivered after 36 weeks' gestation during a 10-year period. Cases were classified into the trial of labor (TOL) or cesarean section (CS) group according to the planned delivery mode. The primary outcome was a composite of adverse outcomes for at least one twin, including intrauterine fetal death (IUFD) after 36 weeks, neonatal death, umbilical artery pH<7.1, 5-min Apgar scores<7, hypoxic ischemic encephalopathy (HIE), meconium aspiration syndrome (MAS), respiratory distress syndrome (RDS), or acute feto-fetal hemorrhage (AFFH). The relationship between outcomes and the planned delivery mode was evaluated using a multiple logistic regression analysis.

RESULTS

We included the 310 pregnancies delivered after 36 weeks' gestation. After excluding 15 patients, the final analysis included 295 MCDA pregnancies: 63% had delivered through TOL and 37% through CS. The incidences of composite adverse outcomes in the TOL and CS groups were 4.3% and 1.9%, respectively. No IUFD, neonatal death, MAS, RDS, or AFFH was observed; two infants in each group developed HIE. Adverse outcomes were not significantly associated with any risk factor, including delivery through TOL.

CONCLUSION

TOL may not influence the perinatal outcomes of MCDA twin pregnancies delivered at ≥36 weeks' gestation.

Twin Birth Considering the Current Results of the "Twin Birth Study"

The rate of caesarean sections in multiple births has grown sharply worldwide. The reason for this may be the results of large retrospective cohort studies from the 1990s, which displayed an increased risk of mortality and morbidity, especially for the second twin, in the case of vaginal births. Multiple monocentric analyses have not been able to confirm this. As a prospective, multi-centre randomised study, the Twin Birth Study published in 2013, in which 105 clinics in 25 countries took part, showed that, under optimum conditions, there was no difference in neonatal and maternal mortality and morbidity if the birth was planned to be vaginal or via caesarean. Detailed analyses, which would be helpful in choosing the type of birth method and obstetric management in the event of vaginal birth, have not previously been published. Retrospective studies must be referred to for this.

The effects of labor and delivery on maternal and neonatal outcomes in term twins: a retrospective cohort study

OBJECTIVE

To compare maternal and neonatal outcomes in twins undergoing a trial of labor versus pre-labor caesarean.

DESIGN

Retrospective cohort study.

SETTING

19 US hospitals from the Consortium on Safe Labor.

POPULATION

Of 2225 twin sets ≥36 weeks' gestation.

METHODS

Maternal (abruption, estimated blood loss, postpartum haemorrhage, transfusion, chorioamnionitis, hysterectomy, ICU admission, death) and neonatal outcomes (birth injury, 5-minute Apgar <7, NICU admission, RDS, TTN, sepsis, asphyxia, NICU length of stay, death) were compared between the trial of labour and pre-labour caesarean groups with univariate and multivariate logistic and linear regression analyses. Similar analyses were performed for actual delivery modes.

MAIN OUTCOME MEASURES

Maternal and neonatal outcomes.

RESULTS

Among the 2225 twin sets, 1078 had a trial of labour, and 65.9% of those delivered vaginally. There was an increased risk for postpartum haemorrhage [OR 2.5, 95% confidence interval (CI) 1.4-4.5] and blood transfusion (OR 1.9, 95%CI 1.2-3.2) for the trial of labour compared with pre-labour caesarean groups. Birth injury only occurred in the trial of labour group, 1% Twin A, 0.4% Twin B. Both twins had a higher risk of 5-minute Apgar <7 with trial of labour compared to pre-labour caesarean (A: OR 3.9, 95%CI 1.05-14.5; B: OR 3.9, 95%CI 1.3-12.3).

CONCLUSION

Term twins undergoing a trial of labour have increased maternal haemorrhage and transfusions along with neonatal birth trauma and lower Apgar scores, but these absolute neonatal occurrences were rare. Trial of labour in twins remains a safe and reasonable option in appropriately selected cases.

Trends in twin pregnancies and mode of delivery during the last 30 years: inconsistency between guidelines and clinical practice

AIM

To investigate the characteristics of twin pregnancies and their mode of delivery over a 30-year period, in order to define the current trends in clinical practice regarding twin deliveries and the factors that influence these practices.

MATERIALS AND METHODS

A retrospective study of twin deliveries at ≥24 weeks of gestation between January 1st, 1981 and December 31, 2010. Data concerning number of twin deliveries, mode of delivery, maternal age, use of ART techniques, parity, gestational age at delivery, birth weight and Apgar scores were collected from labor ward records.

RESULTS

Over the years there has been a statistically significant increase in the number of twin deliveries, twins after IVF, cesarean section rate, maternal age, nulliparity and a statistically significant reduction in term deliveries, mean birth weight and assisted vaginal deliveries. Maternal age, gestational age, parity and conception after IVF are factors related to the risk of performing a cesarean section.

CONCLUSIONS

Despite the lack of adequate scientific evidence concerning the optimal route of delivery in twin pregnancies it seems that over time cesarean section has become the standard of care in most of twin pregnancies. Changes in the demographic characteristics contribute among other factors to this practice.

Caesarean section for preterm birth and, breech presentation and twin pregnancies

Caesarean section incidence is steadily rising worldwide; the major contributor to this rise is pregnancies with previous caesarean section. Hence, it is important to scrutinise carefully the indication of primary caesarean sections. Preterm births, breech presentation and twin pregnancies together complicate 12-18% of all births. The role of caesarean section in these pregnancies is controversial and lacks good evidence-based guidelines. Policy on mode of delivery in these three important obstetric groups is bound to influence overall primary caesarean section rates. In this chapter, we review the evidence on the place of caesarean delivery in these three important groups.

[Rupture of membranes in case of internal podalic version: a risk for cesarean section on the second twin]

OBJECTIVES

To evaluate if internal version with ruptured membranes is a risk factor of cesarean section for the second twin.

PATIENTS AND METHODS

Two hundred and fifty-nine twins vaginal deliveries after 33 weeks of gestation from 1997 to 2009 in a level 3 maternity. A retrospective case-control study comparing two groups: cases of cesarean section on second twin and five twins vaginal deliveries following the case. Active management of the second twin delivery was performed with a short intertwin delivery.

RESULTS

Eleven cesarean sections on the second twin were performed (4.2%). The main indication was failure of internal version. The risk of cesarean section was significantly greater when the internal version was performed with ruptured membranes (OR: 25.4 IC 95% [2.3-275.7] P<0.003) and when intertwin time delivery interval was increased (8.1±5.1 vs 16.7±6.3, P<0.001).

DISCUSSION AND CONCLUSION

The rupture of amniotic membranes before or during the internal podalic version is associated with a risk of failure and cesarean for the second twin. We recommend to perform the internal podalic version with unruptured membranes according to the French recommendations.

Trends in cesarean delivery for twin births in the United States: 1995-2008

OBJECTIVE

To estimate trends and risk factors for cesarean delivery for twins in the United States.

METHODS

This was a cross-sectional study in which we calculated cesarean delivery rates for twins from 1995 to 2008 using National Center for Health Statistics data. We compared cesarean delivery rates by year and for vertex compared with breech presentation. The order of presentation for a given twin pair could not be determined from the available records and therefore analysis was based on individual discrete twin data. Multivariable logistic regression was used to estimate independent risk factors, including year of birth and maternal factors, for cesarean delivery.

RESULTS

Cesarean delivery rates for twin births increased steadily from 53.4% to 75.0% in 2008. Rates rose for the breech twin category (81.5%-92.1%) and the vertex twin category (45.1%-68.2%). The relative increase in the cesarean delivery rate for preterm and term neonates was similar. After risk adjustment, there was an average increase noted in cesarean delivery of 5% each year during the study period (risk ratio 1.05, 95% confidence interval 1.04-1.05).

CONCLUSION

Cesarean delivery rates for twin births increased dramatically from 1995 to 2008. This increase is significantly higher than that which could be explained by an increase in cesarean delivery for breech presentation of either the presenting or second twin.

Is a planned cesarean necessary in twin pregnancies?

OBJECTIVE

Evaluation of elective cesarean section for twin delivery as a standard of care.

DESIGN

Historical cohort in a national database (2 597 twin pregnancies).

SETTING

France.

SAMPLE

Twins with first child in cephalic presentation.

METHODS

Decision analysis.

MAIN OUTCOME MEASURES

All neonatal complications, i.e. death, whether intrapartum or in the delivery room or the immediate postpartum period, or neonatal transfer to intensive (or special) care, or trauma, of one or both twins.

RESULTS

When we focused on neonatal complications for either or both twins, the strategy of planned vaginal delivery was preferable; the weight of its decision tree branch was lower than that for planned cesarean (26.5 vs. 31.7). If only twin 2 was considered, vaginal delivery was also preferred (weight of vaginal delivery=27.6 vs. 32.7 for planned cesarean). As long as the morbidity and mortality of twin 1 or twin 2 or both during a cesarean for twin 2 in the case of planned vaginal delivery does not exceed 31.5%, all else being equal, vaginal delivery should be preferred to a planned cesarean for twin 1 and twin 2. The two-variable sensitivity analysis confirmed the robustness of the results.

CONCLUSIONS

The results of our study do not support a policy of planned cesarean delivery for twin pregnancies at and after 34 weeks of gestation.

LEVEL OF EVIDENCE

II.

Recorded pregnancy histories of the mothers of singletons and the mothers of twins: a longitudinal comparison

A population-based record linkage case cohort of 239,995 births, to 119,214 women, born in Western Australia from 1980 to 2001 inclusive, was used to measure the recording of selected indicators of maternal health (current and prior) during pregnancy. We compared records of women with singleton pregnancies with that in twin pregnancies Mothers of first- and second-born singletons (n = 117,647) were compared with women with a first-born singleton followed by twins (n = 1,567). Binary indicators were used to calculate population prevalence of medical conditions, pregnancy complications and birth outcomes. Infant outcomes included stillbirth, low birthweight, preterm birth and birth defects. Women with twins were significantly older and taller, with similar rates of medical conditions and pregnancy complications during first singleton pregnancies compared with women with two consecutive singletons. However, during their second pregnancy, women with twins had significantly higher rates of essential hypertension, pre-eclampsia, threatened abortion, premature rupture of the membranes and ante partum hemorrhage with abruption than women with singletons. For both groups, maternal conditions in the first pregnancy were underreported in the second pregnancy, including diabetes, epilepsy, asthma, chronic renal dysfunction and essential hypertension. At the second birth, twins were 3 times more likely to be stillborn, 17 times more likely to be low birthweight and 4 times more likely to be delivered preterm compared with singletons. This research demonstrates the importance for epidemiologists and others, of having access to a complete maternal medical history for analyses of risks associated with maternal, infant and childhood morbidity.

[Modes of deliveries of twins as a function of their presentation. A study of 371 pregnancies]

OBJECTIVE

In France, global rate of caesarian section in twin pregnancies has been 50.2% in 2003. Modes of delivery according to different twin presentations remain controversial in the literature. The purpose of our study is to analyze our practice of twin deliveries in a 5-year period, with neonatal outcomes.

PATIENTS AND METHODS

Among 22,243 women having delivered in our maternity (22 weeks and over) during the study period, the study population consisted of 371 twin pregnancies, of which 305 after 33 weeks gestation.

RESULTS

Different presentations were relatively identical whatever the gestational age of pregnancies: the "cephalic-cephalic" presentation represented 60 to 70% of the total, the "cephalic-breech" presentation approximately 10% while the "breech-cephalic" or "breech-breech" presentations approximately 8% each. Mean terms of pregnancies were 35.2 ± 2.8 weeks, mean birthweight being 2243 ± 561 g. C-section rate was 53.5%. When the first twin was in cephalic presentation, C-section rate was 40% while it was almost 100% when the first twin was in breech or "other" presentations.

CONCLUSION

There were no significant differences in neonatal outcomes (mean birthweights, Apgar scores, transfers in neonatology, perinatal deaths) according to different mode of deliveries (vaginal or C-sections). Our policy of planned cesarean section may need to be revised.

Neonatal outcomes of twins according to birth order, presentation and mode of delivery: a systematic review and meta-analysis

BACKGROUND

The optimal mode of delivery for twins is undetermined.

OBJECTIVE

To review literature regarding the neonatal outcomes following twin delivery.

DATA SOURCES

Searches were conducted in PubMed, Medline, Embase, Cochrane library and reference lists.

SELECTION CRITERIA

Studies selection criteria were: both twins alive at labour, outcomes stratified for birth order, presentation, planned and actual delivery mode. Eighteen articles were included in the meta-analysis (39, 571 twin sets).

DATA COLLECTION AND ANALYSIS

The Meta-analysis of Observational Studies in Epidemiology guidelines were followed. Interstudy heterogeneity (I(2) ) was tested. A fixed model was generated whenever I(2)<25%. Pooled odds ratios (OR) with 95% CI were computed. Intergroup comparison was significant if 95% CI did not encompass 1. The first and second twins were indicated as Twin A (TA) and Twin B (TB), respectively.

MAIN RESULTS

Neonatal morbidity was lower in TA than TB (3.0 versus 4.6%; OR 0.53; 95% CI 0.39-0.70). TA experienced neonatal death less often than TB (0.3 versus 0.6%; OR 0.55; 95% CI 0.38-0.81). No differences were noted between vertex and non-vertex and attempted vaginal delivery versus planned caesarean section in either TA or TB. In TA, neonatal morbidity was lower after vaginal delivery (1.1%) than caesarean section (2.2%; OR 0.47; 95% CI 0.27-0.82). Neonatal death was not associated with actual delivery mode. In TB, morbidity following combined delivery (19.8%) was higher than after vaginal delivery (9.5%; OR 0.55; 95% CI 0.41-0.74) or caesarean section (9.8%; OR 0.47; 95% CI 0.43-0.53). When outcomes were stratified for both presentation and delivery mode, mortality rate was lower after vaginal delivery than caesarean section for both vertex and nonvertex TB. AUTHOR'S CONCLUSION: An attempt at vaginal delivery should be considered in twin pregnancies with vertex/vertex presentation.

[Is vaginal delivery in twin pregnancy still an option? An analysis of the literature data]

The aim of this review was to analyze the nature of the data and practices reported in the literature in order to determine if vaginal delivery of twin gestations with a first twin in cephalic presentation after 34 weeks still remains an option. Compared to cesarean, large retrospective population-based studies demonstrated increased neonatal morbidity and mortality of the second twin associated with vaginal delivery. Some then suggested systematic planned cesarean could protect second twins from increased neonatal mortality and morbidity. These results have not been confirmed in hospital retrospective studies in which candidates for vaginal delivery were carefully selected, and second twin delivery actively managed, with internal version when the fetal head is above a 0 station in case of cephalic presentation and with systematic immediate total breech extraction in case of non cephalic presentation. Taking into account the poor external validity of the population-based studies, and the reassuring results of the hospital retrospective studies, attempted vaginal delivery after 34 weeks, when the first twin is in cephalic presentation, still appears as a safe option in low risk populations. Progress in the assessment of the risks associated with the mode of delivery could result from a large nationwide observational prospective study, a randomized trial being, even more than in the breech delivery issue, an inappropriate method for evaluating these risks.

Determinants of perinatal mortality and serious neonatal morbidity in the second twin

OBJECTIVE

To identify potential determinants of perinatal mortality and neonatal morbidity among second twins relative to first twins.

METHODS

A retrospective cohort design was used to study twin deliveries in Nova Scotia from 1988 to 2002. Monoamniotic or conjoined twins and twin pairs with major congenital anomaly or antepartum fetal death of either twin were excluded. The primary outcome was a composite measure of perinatal mortality and neonatal morbidity, including birth asphyxia, respiratory distress, neonatal trauma, and infection. Risk of adverse outcome of second twins relative to first-born co-twins was determined by matched-pair analysis.

RESULTS

Of 1,542 twin pairs, the second twin was at greater risk of composite adverse outcome (relative risk [RR] 1.62, 95% confidence interval [CI] 1.38-1.9) than the first twin. This excess risk was evident independent of presentation, chorionicity, or infant sex but was associated with planned vaginal delivery, birth weight discordance, and prolonged interdelivery interval. Term second twins were less likely to suffer excess morbidity with elective cesarean (RR 1.0, 95% CI 0.14-7.10) than with planned vaginal delivery (RR 3.0, 95% CI 1.47-6.11). The major contributors to neonatal morbidity in the second twin were birth asphyxia at 37 weeks or later and respiratory distress syndrome at less than 37 weeks.

CONCLUSION

The second twin is at greater risk of adverse perinatal outcome than the first twin, independent of presentation, chorionicity, or infant sex. Planned vaginal delivery, birth weight discordance, and prolonged interdelivery interval increase this infant risk. Elective cesarean delivery at term may improve perinatal outcome for the second twin. However, the number of cesarean births required to prevent one case of composite adverse outcome, assuming causality, was 33.