Twin-to-twin delivery time: neonatal outcome of the second twin

The optimal cutoff for intertwin delivery interval: A retrospective cohort study

OBJECTIVE

To determine the cutoff of intertwin delivery intervals (IDIs) as a predictor for neonatal acidemia.

METHOD

This retrospective cohort study was conducted at a single tertiary care center. Women attempting vaginal delivery of twins between 2010 and 2019 and who reached the second stage of labor were included. The cutoff point for prolonged IDI was established using a receiver operating characteristic (ROC) curve and Youden's J statistic. Maternal and neonatal outcomes were compared between short and prolonged IDI cohorts.

RESULTS

A total of 461 women were included in the study. A cutoff time of 10 min was found to be the best predictor for neonatal acidemia (arterial cord pH ≤ 7.1), with a sensitivity of 90% and a specificity of 59%. Second twins delivered more than 10 min after the first twin were more likely to be acidemic and to have a 5-min Apgar score of 7 or less (13.5% vs 3.3%, P = 0.01, and 8.4% vs 3.2%, P = 0.02, respectively). An IDI of more than 10 min was also associated with increased rate of cesarean delivery and placental abruption (13.5% vs 0.8%, P < 0.001, and 3.4% vs 0.8%, P = 0.047, respectively). No other adverse maternal or neonatal outcomes were statistically significant between cohorts.

CONCLUSION

An IDI of more than 10 min is associated with a higher risk for neonatal academia, with a low 5-min Apgar score, and higher cesarean delivery and placental abruption rates. These findings provide insights that are valuable when counseling and managing twin pregnancies attempting vaginal delivery. Interventions aimed at shortening the IDI should be considered to prevent adverse neonatal outcomes.

Exploring the Optimal Intertwin Delivery Interval for Vaginal Delivery

The effect of prolonged intertwin delivery interval (IDI) is not well studied. This work aimed to assess the inflection point for Cesarean delivery (CD) and associated adverse maternal and neonatal outcomes. This was a retrospective cohort study at a single tertiary care center. The study included women with twin pregnancies in 2010-2019 who reached the second stage of labor, and assessed the most predictive cutoff for CD using Youden J statistic and compared adverse maternal and neonatal outcomes between short and prolonged intertwin delivery intervals. A total of 461 gravidas reached the second stage of labor and were included in the study. Using the ROC curve and Youden J statistic, the IDI cutoff was set at 15 min (80% sensitivity, 75% specificity, p < 0.001), with 312 women in the short and 149 in the prolonged IDI groups. Women in the prolonged IDI group were less likely to deliver the second twin vaginally (75.8% vs. 93.3%, p < 0.001). Postpartum hemorrhage (PPH) (39.1% vs. 24.7%, p = 0.01), and placental abruption (4% vs. 1%, p = 0.03) were more likely to occur in the prolonged IDI group. An increased rate of neonatal acidemia and low 5-min Apgar score were also found in the prolonged IDI group (15.7% vs. 4.3%, P = 0.01, 9.7% vs. 3.5%, p = 0.008; respectively). IDIs of more than 15 min are associated with increased risk of adverse maternal and neonatal outcomes. These findings should be used for counseling and managing twin pregnancies attempting vaginal delivery.

Risk Factors for Prolonged Intertwin Delivery Interval and Associated Maternal and Second Twin Morbidity

OBJECTIVE

This work aimed to identify possible risk factors and the morbidity associated with prolonged intertwin delivery interval (IDI).

STUDY DESIGN

A retrospective cohort study at a single tertiary care center. Women with twin gestations who reached the second stage of labor between January 2010 and December 2019 were included in the study. Demographic and clinical characteristics were compared between short IDI (≤15 minutes) and prolonged IDI (>15 minutes). The primary outcome was the rate of 5-minute Apgar score ≤ 7.

RESULTS

A total of 461 women were included; 312 of whom were in the short IDI group and 149 were in the prolonged IDI group. Rates of 5-minute Apgar score ≤ 7 and neonatal acidemia were significantly higher in the prolonged IDI group (3.5 vs. 9.7%, p = 0.008; 4.3 vs. 15.7%, p = 0.01, respectively). Vaginal delivery was less likely to occur in the prolonged IDI group (75.8 vs. 93.3%). Placental abruption and hemoglobin drop ≥ 3 g/dL were more prevalent in the prolonged IDI group (4 vs. 1%, p = 0.03; 39.1 vs. 24.7%, p = 0.01, respectively). In the multivariate analysis, age ≥ 30 years (adjusted odds ratio [aOR]: 1.76, p = 0.01), nulliparity (aOR: 1.66, p = 0.03), and birth weight ratio ≥ 1.2 (aOR: 1.92, p < 0.05) were associated with prolonged IDI.

CONCLUSION

Prolonged IDI is associated with an increased risk for neonatal acidemia and low 5-minute Apgar score, and with an increased rate of cesarean delivery, placental abruption, and hemoglobin drop ≥ 3 g/dL. Advanced maternal age, nulliparity, and twin birth weight ratio ≥ 1.2 are associated with prolonged IDI.

KEY POINTS

· Prolonged was found to be associated with higher neonatal acidemia and lower 5-minute Apgar score.. · Prolonged IDI is also associated with increased rate of cesarean delivery, placental abruption, and blood loss.. · Advanced maternal age, birth weight discordancy, and nulliparity were associated with prolonged IDI..

Mode of delivery in multiple pregnancies

The mode of delivery in multiple pregnancies has been subject to vigorous debates during the last few decades. Although observational and retrospective data were accumulated, it was not until the publication of the Twin Birth Study that evidence-based recommendations could emerge. However, although some of the most pressing questions were answered by the Twin Birth Study, other questions were left outside the scope of the study. The questions were of great interest and included the following topics: the impact of gestational age, the influence of chorionicity, and the generalizability of the results for women with a previous uterine scar. The current evidence supported a trial of labor in dichorionic-diamniotic or monochorionic-diamniotic twin pregnancies in which the first twin is in cephalic presentation at ≥32 weeks' gestation. Dichorionic-diamniotic, monochorionic-diamniotic, and monochorionic-monoamniotic twins should be delivered at 37 0/7 to 38 0/7, 36 0/7 to 37 0/7, and 32 0/7 to 34 0/7 weeks' gestation, respectively. Breech extraction done by a competent healthcare provider seemed to offer a higher chance of successful vaginal delivery of the second twin than the external cephalic version. The current data did not allow for a clear recommendation regarding the mode of delivery in very preterm birth of low birthweight twins, but most studies did not demonstrate a clear benefit of cesarean delivery vs trial of labor. Furthermore, a trial of labor seemed safe in women with a previous cesarean delivery. Cesarean delivery is likely beneficial for twin pregnancies with the first twin in breech presentation, monochorionic-monoamniotic twins, and higher-order multiple pregnancies. In all multiple pregnancies, delivery should be performed by an experienced practitioner competent in multiple pregnancy deliveries.

Effect of Chorionicity on Umbilical Cord Blood Acid-Base Analysis of the Second Twin

Our objective was to determine whether chorionicity affects umbilical cord blood acid-base parameters of the second twin. This was a retrospective cohort of twin pregnancies delivered at ≥23 weeks of gestation at a tertiary hospital from 2010 to 2016. Patients were included if arterial and venous umbilical cord gas results were available for both newborns and chorionicity was confirmed histologically. Exclusion criteria included intrauterine fetal demise of either twin prior to labor, major fetal anomalies, monoamnionicity, uncertain chronicity and twin-to-twin transfusion syndrome. The primary outcome evaluated was the umbilical artery (UA) pH of the second twin. A total of 593 dichorionic (DC) and 86 monochorionic (MC) twin pregnancies were included. No difference in UA pH was observed between MC and DC twins. Among vaginal deliveries (n = 97), the UA pH of the first twin was higher than the second twin (7.26 vs. 7.24; p = .01). Twin-to-twin delivery interval (TTDI) ≥20 min was associated with a higher UA pH in the first twin compared to the second twin (7.25 vs. 7.16, respectively; p = .006). Multivariable logistic regression was used to predict arterial pH < 7.20 for the second twin; the most predictive factors were arterial pH < 7.20 for the first twin, chronic hypertension and prolonged TTDI. Chorionicity was not associated with any acid-base parameter of umbilical cord blood in either the first or second twin. No differences in neonatal outcomes were observed based on chorionicity or birth order. Populations with a lower cesarean delivery rate may yield different findings.

Pre- and Perinatal Characteristics Associated with Apgar Scores in a Review and in a New Study of Dutch Twins

A literature review was carried out to identify pre and perinatal characteristics associated with variation in Apgar scores in population-based studies. The parameters identified in the literature search were included in the classical twin design study to estimate effects of pre and perinatal factors shared and nonshared by twins and to test for a contribution of genetic factors in 1- and 5-min Apgar scores in a large sample of Dutch monozygotic (MZ) and dizygotic (DZ) twins. The sample included MZ and DZ twins (N = 5181 pairs) recruited by the Netherlands Twin Register shortly after birth, with data on prenatal characteristics and Apgar scores at first and/or fifth minutes. The ordinal regression and structural equation modeling were used to analyze the effects of characteristics identified in the literature review and to estimate genetic and nongenetic variance components. The literature review identified 63 papers. Consistent with the review, we observed statistically significant effects of birth order, zygosity and gestational age (GA) for 1- and 5-min Apgar scores of both twins. Apgar scores are higher in first-born versus second-born twins and DZ first-born versus MZ first-born twins. Birth weight had an effect on the 5-min Apgar of the first born. Fetal presentation and mode of delivery had different effects on Apgar scores of first- and second-born twins. Parental characteristics and chorionicity did not have significant main effects on Apgar scores. The MZ twins' Apgar correlations equaled the DZ Apgar correlations. Our analyses suggest that individual differences in 1- and 5-min Apgar scores are attributable to shared and nonshared pre and perinatal factors, but not to genotypic factors of the newborns. The main predictors of Apgar scores are birth order, zygosity, GA, birth weight, mode of delivery and fetal presentation.

Inter-twin delivery interval, short-term perinatal outcomes and risk of caesarean for the second twin

OBJECTIVE

To examine the association between inter-twin delivery interval and short-term perinatal outcomes of the second twin after vaginal delivery of the first twin.

METHODS

Retrospective cohort study including twin pregnancies with a vaginal delivery of the first twin between January 2011 and September 2017 in a tertiary hospital in Melbourne, Australia. The main outcome measure was a composite of adverse neonatal outcome (at least one of perinatal death, admission to neonatal intensive care unit (NICU), endotracheal intubation, Apgar <7 at five minutes and cord lactate >4.0 mmol/L). Proportions of adverse outcomes for the second twin were compared between groups of intervals ≤ or >10 and ≤ or >30 min.

RESULTS

The composite adverse neonatal outcome occurred in 201 (58.2%) and a caesarean section occurred in seven cases (2%) of the 345 pregnancies included. Delivery interval was associated with higher cord lactate. Low Apgar scores were more frequent with intervals >30 min (17.9% vs 6.6%, P = 0.03), as well as caesarean section for the second twin (10.7% vs 1.3%, P = 0.01). Composite adverse outcome and admission to NICU were not significantly influenced by the delivery interval. Predictors of adverse outcome were gestational age, abnormal cardiotocography and breech delivery of the second twin.

CONCLUSION

The inter-twin delivery interval is associated with higher rates of low Apgar scores and higher cord lactate for the second twin. These associations do not translate into higher rates of admission to NICU and their long-term clinical implications are uncertain.

Delivery of the second twin: influence of presentation on neonatal outcome, a case controlled study

Background

Spontaneous vaginal twin delivery after 32nd week of gestation is safe when first twin presenting cephalic. Aim of this study is to identify obstetric factors influencing the condition of second twin and to verify whether non-cephalic presentation and vaginal breech delivery of the second twin is safe.

Methods

This is a retrospective case controlled cohort study of 717 uncomplicated twin deliveries ≥32 + 0 weeks of gestation from 2005 to 2014 in two tertiary perinatal centers. Obstetric parameters were evaluated in three groups with descriptive, univariate logistic regression analysis for perinatal outcome of second twins.

Results

The three groups included twins delivered by elective cesarean section ECS (n = 277, 38.6%), by unplanned cesarean section UPC (n = 233, 32.5%) and vaginally (n = 207, 28.9%). Serious adverse fetal outcome is rare and we found no differences between the groups. Second twins after ECS had significant better umbilical artery UA pH (p < 0.001) and better Apgar compared to UPC (p = 0.002). Variables for a fetal population “at risk” for adverse neonatal outcome after vaginal delivery (UA pH < 7.20, Apgar 5´ < 9) were associated with higher gestational age (p = 0.001), longer twin-twin interval (p = 0.05) and vacuum extraction of twin A (p = 0.04). Non-cephalic presentation of second twins was not associated (UA pH < 7.20 OR 1.97, CI 95% 0.93–4.22, p = 0.07, Apgar 5´ < 9 OR 1.63, CI 95% 0.70–3.77, p = 0.25, Transfer to neonatal intermediate care unit p = 0.48). Twenty-one second twins (2,9%) were delivered by cesarean section following vaginal delivery of the first twin. Even though non-cephalic presentation was overrepresented in this subgroup, outcome variables were not significantly different compared to cephalic presentation.

Conclusions

Even though elective cesarean means reduced stress for second twins this seems not to be clinically relevant. Non-cephalic presentation of the second twin does not significantly influence the perinatal outcome of the second twin but might be a risk factor for vaginal-cesarean birth.

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.

Multifetal Gestation: Mode of Delivery

The incidence of twin, triplet, and higher-order multifetal gestations, has increased dramatically in the recent years. Rates of cesarean delivery for multiple gestations also have risen, largely due to the perception that cesarean delivery improves neonatal outcomes. Until recently, data to support the "best" mode of delivery for multifetal gestations was lacking. However, recent high-quality retrospective studies and a prospective randomized trial now offer the obstetrician guidance as to the optimal intrapartum management of women with multiple gestations.

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.