Intertwin Delivery Interval Research Articles

Emergency cervical cerclage in delayed-interval delivery of twin pregnancies: a scoping review

BackgroundThe protocol for delayed-interval delivery of the second twin in twin pregnancies has not been standardized. Cervical cerclage is often performed, but its use is debated. To conduct a scoping review on cervical cerclage for prolonging the intertwin delivery interval and improving second twin survival and maternal outcomes after preterm delivery or spontaneous abortion of the first twin in twin pregnancies.MethodsSeven Chinese and English language databases were searched from inception to March 1, 2023, including PubMed, The Cochrane Library, Web of Science, CNKI, Wanfang Data, VIP Chinese Science Journal Database, and Sinomed. Relevant observational studies that assessed the effectiveness of the use of cervical cerclage in delayed-interval delivery of twins were screened and selected, and raw data were extracted, and descriptive statistics and chi-square analysis were performed.ResultsA total of 102 articles were retrieved. After screening and exclusion of duplicate and irrelevant articles, 22 articles meeting the inclusion criteria were obtained. Studies in which cerclage was performed reported longer intertwin delivery intervals than those that did not perform cerclage, and the difference was statistically significant. The cerclage group also tended to have lower rates of chorioamnionitis and maternal complications, but the difference between the two groups was not statistically significant.ConclusionAfter excluding patients with contraindications, emergency cervical cerclage can be considered in cases of spontaneous abortion of the first twin in twin pregnancies to prolong the gestation and improve the prognosis of the remaining fetus until it becomes viable and increases its birth weight.

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.

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

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

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

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

Vaginal delivery of second twins: factors predictive of failure and adverse perinatal outcomes.

This study was performed to explore factors associated with adverse perinatal outcomes for second twins and to identify predictive factors for successful vaginal delivery of the second twin after vaginal delivery of the first twin. This 10-year retrospective study included 231 cases of twin pregnancies in which vaginal delivery of the second twin was attempted after vaginal delivery of the first twin. The relationships of obstetric characteristics with the composite adverse perinatal outcome of the second twin were analysed. Predictive factors for successful vaginal delivery of the second twin were also explored. Gestational age <32 weeks was the only independent risk factor for the composite adverse perinatal outcome and neonatal intensive care unit admission for the second twin. A longer inter-twin delivery interval was associated with greater risk of caesarean delivery of the second twin, but it did not increase the risk of an adverse perinatal outcome. Non-vertex presentation of the second twin at delivery was independently associated with caesarean delivery (9.0% vs 2.0%, P=0.03). For second twins in breech presentation, caesarean delivery was associated with the presence of less experienced birth attendants. Among second twins born to mothers who had attempted vaginal delivery, adverse perinatal outcomes were mainly related to prematurity. The presence of more experienced birth attendants may contribute to successful vaginal delivery of the second twin, particularly for twins in non-vertex presentation.

Internal podalic version of second twin: Improving feet identification using a simulation model

BackgroundPodalic version and breech extraction require high obstetrical expertise. Identifying fetal extremities is the first crucial step for trainees. When this skill is not polished enough, it increases the inter-twin delivery interval and can even jeopardize the whole manoeuver. Material and methodsWe present a model for simulating and training this specific skill, with obstetrical mannequin, and 3D printed hands and feet. Five feet and five hands (five rights and five lefts of each one) were printed in 3D after initial ultrasound acquisition of a near term fetus. Each foot and hand, was individually set in a condom filled with 100 cc of water and closed with a knot. A Sophie’s Mum Birth Simulator Version 4.0 de MODEL-med was placed on the edge of the table. Each hand and foot was inserted into the pelvic mannequin.An evaluation of the students’ skills using this model was performed. A significant reduction of the global mean to extract the first foot and all the feet was noticed at three month of interval. ConclusionThis model is an option to train and assess a crucial skill for version and breech extraction.

Rates of Cesarean Conversion and Associated Predictors and Outcomes in Planned Vaginal Twin Deliveries.

Twin vaginal deliveries (VDs) are often performed in the operating room (OR) given the risk of conversion to cesarean delivery (CD) for the aftercoming twin. We aim to investigate the rates of conversion to CD for planned twin VDs and identify predictors and outcomes of conversion. A retrospective cohort study of all women who underwent a planned twin VD at two large academic medical centers over 4 years. Demographic and outcome data were chart abstracted. Various statistical tests were used to evaluate the influence of perinatal variables on mode of delivery and identify possible predictors of conversion. Eight hundred and eighty-five twin deliveries were identified, of which 725 (81.9%) were possible candidates for VD. Of those, 237 (32.7%) underwent successful VD of twin A. Ninety-five (40.1%) had a nonvertex second twin at time of delivery. Conversion to CD occurred in 10 planned VDs (4.2%). Conversions were higher with spontaneous labor (relative risk [RR]: 2.1; 95% confidence interval [CI] 1.6-2.7; p = 0.003), and having an intertwin delivery interval greater than 60 minutes (RR: 5.1; 95% CI: 2.5-10.8; p < 0.001). Nonvertex presentation of twin B, type of delivery provider, or years out in practice of delivery provider were not significantly different between groups. There were no significant differences in neonatal outcomes between VD and conversion groups. There was a significant association between use of forceps for twin B and successful VD (p = 0.02), with 84.6% in the setting of a nonvertex twin B. Successful VD was achieved in planned VD of twins in 95.8% of cases, and there were no significant differences in maternal and fetal outcomes between successful VD and conversion to CD for twin B. With the optimal clinical scenario and shared decision-making, performing vaginal twin deliveries in labor and delivery rooms should be discussed. · There is a propensity to perform twin vaginal deliveries in the operating room.. · Rates of conversion to cesarean section are very low.. · There are no significant differences in perinatal outcomes with conversion..

Long term outcome of second twins born to mothers who attempted vaginal delivery a retrospective study

ObjectiveTo evaluate mortality and long term neurodevelopmental outcomes of the second twins born to mothers who attempted vaginal delivery. Study designTwo hundred and twenty-seven eligible cases of second twin born to mothers who attempted vaginal delivery were identified retrospectively in a ten-year period. Information on adverse long term outcomes (a composite of mortality and neurodevelopmental disorders) were retrieved from their electronic medical record, and the risk factors were determined. ResultsThe median follow-up duration was 8 years (range 4-13 years). Adverse composite long term outcomes were observed in 6.6% (15/227). Gestation at delivery < 32 week (p = 0.001) and inter-twin delivery interval of > 30 min (P = 0.000) were significantly associated with adverse long term outcomes of the second twin on multivariate analysis. Second twins in the combined vaginal- caesarean birth group had no significant increase in adverse outcomes compared to those in the vaginal-vaginal birth group. ConclusionAdverse long term outcomes were uncommon among second twins born to mothers who attempted vaginal delivery. Adverse outcomes were associated with prematurity and inter-twin delivery interval of more than 30 min, but not with actual mode of delivery.

387: Neonatal morbidity of cephalic second twins according to the obstetrical strategy adopted at delivery

To assess neonatal mortality and morbidity of cephalic second twins according to the obstetrical strategy adopted after vaginal birth of the first twin, either internal version followed by total breech extraction, as recommended by the French College of Gynecologists and Obstetricians, or pushing efforts. In this planned secondary analysis of the JUMODA cohort, a national prospective population-based study of twin deliveries conducted from 02/2014 to 03/2015 in 176 hospitals performing more than 1,500 annual deliveries in France, we included cephalic second twins after vaginal birth of the first twin at 32 weeks and more. Intrauterine fetal deaths, fetal malformations, twin-to-twin transfusion syndromes, monoamniotic pregnancies, and unknown presentations and managements of second twins were excluded. The primary outcome was a composite of neonatal mortality and morbidity. To control for potential confounders, we used multivariate Poisson regression models. Of 2261 cephalic second twins included in the study, 494 (21.8%) were born in breech presentation after internal version and total breech extraction and 1767 (78.2%) in cephalic presentation after pushing efforts. The mean inter-twin delivery interval was shorter in the internal version group compared to the pushing efforts group (6.6 ± 5.9 versus 10.0 ± 13.0, p<0.01). Neither rates of cesarean for the second twin (10/494 (2.0%) versus 61/1767 (3.2%), p=0.1) nor rates of composite neonatal mortality and morbidity (17/494 (3.4%) versus 36/1767 (2.2%); aRR 1.4, 95% CI 0.8-2.4) differed significantly between the two groups. Compared with pushing efforts after vaginal birth of the first twin, internal version followed by total breech extraction of cephalic second twins is associated with shorter inter-twin delivery intervals but not with improved neonatal outcomes.

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

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. 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 >30min. 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 >30min (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. 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.

What is the effect of intertwin delivery interval on the outcome of the second twin delivered vaginally?

Objective: Optimal management of twin deliveries is controversial. We aimed to assess if intertwin delivery interval, after vaginal delivery of the first twin, may have an influence on adverse neonatal outcomes of the second twinStudy design: This is a retrospective observational study including diamniotic twin pregnancies with vaginal delivery of the first twin, between January 2000 and July 2017. Inclusion criteria were diamniotic pregnancies and vaginal delivery of the first twin. We excluded higher twin order, monoamniotic pregnancies, cesarean delivery of the first twin and patients with missing data.Results: A number of 400 diamniotic twin pregnancies met the inclusion criteria and were divided, considering intertwin delivery interval into (1) ≤30 minutes (n = 365); and (2) >30 minutes (n = 35). Considering the two study groups, maternal and first twin characteristics and outcomes were similar. Second twin reported higher incidence of cesarean section and vacuum delivery, but similar incidence of neonatal adverse outcomes, in case of intertwin interval >30 minutes. At multivariate analysis, a difference between second and first twin weight ≥25% was correlated to neonatal adverse outcome, while we did not found this correlation with a cut-off of 30 minutes.Conclusions: In our study, growth discrepancy between twins was significantly correlated to adverse neonatal outcomes, while intertwin delivery time was not an influencing factor. So, in line with this result, in our clinical practice, we do not use a fixed time in which both twins should be delivered, neither in monochorionic nor in dichorionic pregnancies, when fetal wellbeing was demonstrated during labor.

Neonatal hypoxia of the second twin after vaginal delivery of the first twin: what matters?

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.

Effect of inter-twin delivery interval on umbilical artery pH and Apgar score in the second twin.

To examine the effect of inter-twin delivery interval on umbilical artery pH and Apgar score of the second twin after vaginal delivery of the first twin. Retrospective study conducted at a single teaching hospital. All pregnant women with twin gestation who delivered the first twin vaginally at more than 24weeks between 1995 and 2015 were included. Major malformations and intrauterine deaths of one or both twins were excluded. Women were divided into those who had an inter-twin delivery interval of less than 30 minutes (group 1) or 30 minutes or more (group 2). Primary outcome was umbilical artery pH less than 7.1 and/or Apgar score less than 7 at 5minutes of the second twin. Generalized linear regression with log was performed to evaluate the association with delivery interval. Of 88145 deliveries during this period, 1955 (2.2%) were twins. Overall, 713 twin pregnancies, 596 (83.6%) in group 1 and 117 (16.4%) in group 2, were eligible and included. Mean inter-delivery interval was 11.0±6.5 and 52.5±31.5minutes in groups 1 and 2, respectively. After adjusting for variables found significantly different between the groups in univariate analysis, inter-delivery interval of less than 30 minutes or 30 minutes or more was not a significant risk factor for pH less than 7.1 and/or Apgar less than 7 (P=.91). The cesarean rate for delivery of the second twin after vaginal delivery of the first twin was 4.3% overall, with a higher rate among group 2 compared with group 1 (18.2% and 3.2%, respectively; P=.001). The second twin's Apgar score and cord artery pH are probably not affected when the inter-twin delivery interval exceeds 30minutes.

848: Intertwin delivery interval and associated maternal and neonatal outcomes

848: Intertwin delivery interval and associated maternal and neonatal outcomes

Umbilical Arterial Blood Gas and Perinatal Outcome in the Second Twin according to the Planned Mode of Delivery

To compare umbilical arterial gas parameters in the second twin of twin pregnancies according to the mode of delivery. We retrospectively analyzed the medical records of twin deliveries after 34 weeks of gestation for 3 years. Excluding the cases which underwent emergency cesarean delivery during trial of labor, a total of 79 twin gestations had umbilical arterial blood gas values available and were and divided into cesarean delivery group (N=40) and vaginal delivery group (N=39). The mean differences of umbilical arterial blood parameters and the Apgar score between the first and second twin in each pregnancy were compared according the mode of delivery. The differences of umbilical arterial gas parameters between twin siblings showed no significant difference according to the mode of delivery. With regard to the 1 minute and 5 minute Apgar scores, the differences between twin siblings are significantly increased in vaginal delivery group compared to cesarean delivery group (p=0.048, and p=0.038, respectively). In comparing the 28 cases delivered vaginally with an inter-twin delivery interval < 10 minutes and 40 cases delivered by cesarean section, no significant differences were observed in the umbilical arterial gas parameters and Apgar scores. The inter-twin umbilical arterial blood gas parameters according to the mode of delivery showed no difference. For twin deliveries, it is relatively safe to plan for a vaginal delivery, but an effort should be made to reduce the inter-twin delivery interval time.

Outcome of the second twin

ObjectiveTo evaluate the outcome of the second twin (T2) in twins attempting a vaginal delivery. Data were collected over a 5-year period from 2004 to 2009 from the multiple pregnancy...

Neonatal Outcomes of Twin Pregnancy According to the Planned Mode of Delivery

To assess neonatal morbidity in twin pregnancy according to the planned mode of delivery. A retrospective cohort study of 758 consecutive sets of twins born after 35 weeks of gestation with a cephalic-presenting first twin was undertaken in a level III maternity unit in which active management of the second twin delivery is performed routinely. The primary outcome was a composite measure of neonatal mortality and morbidity, including pH less than 7.0, 5-minute Apgar score less than 4, neonatal intensive care unit transfer more than 4 days, pneumothorax, and fracture. Control for potential confounders was performed by excluding from the analysis women who experienced pregnancy complications and by using logistic regression models. Vaginal or cesarean delivery was planned for 657 (86.7%) and 101 (13.3%) women, respectively. Among planned vaginal deliveries, 515 (78.4%) patients delivered both twins vaginally, 139 (21.1%) had a cesarean delivery during labor, and 3 (0.5%) had cesarean delivery for the second twin. After vaginal birth of the first twin, the mean intertwin delivery interval was 4.9+/-3.2 minutes. When patients who experienced pregnancy complications were excluded (n=202), the neonatal composite morbidity for the second twin did not differ between planned cesarean and planned vaginal delivery (5.0% compared with 4.7%, adjusted odds ratio 1.5, 95% confidence interval 0.3-7.4, P=.63). Neonatal composite morbidity of first twins did not differ between groups. For twin gestations with a cephalic-presenting first twin, planned vaginal delivery after 35 weeks of gestation in selected women remains a safe option in centers used to active management of the second twin delivery.

Relationship between Intertwin Delivery Interval and Metabolic Acidosis in the Second Twin

This study sought to assess the relationship between intertwin delivery interval (ITDI) and metabolic acidosis in the second twin at birth using a retrospective twin delivery cohort from a tertiary-level teaching hospital. Twin births were identified from an obstetrical database during a 10-year period from 1994 to 2004. Mean arterial cord pH and base deficit among different ITDIs were compared by analysis of variance. Logistic regression models were used to estimate effects of ITDI on metabolic acidosis. The incidence of metabolic acidosis in the second twin was defined as pH < 7.0, and base deficit was defined as >or= 12 mmol/L at birth. After excluding those pregnancies with both twins delivered by cesarean section, birthweight less than 750 g of either twin, antepartum death of either twin, or second twins with missing cord arterial pH, we had 310 twin pairs left for final analysis. Mean pH was significantly lower and base deficit significantly higher for second twin after ITDI exceeded 60 minutes. The incidence of metabolic acidosis increased with increasing ITDI (chi2 test for linear trend, P = 0.02) and the risk of metabolic acidosis (odds ratio, 22.6; 95% confidence interval, 2.5 to 494.1) was increased in the second twins with ITDI longer than 60 minutes compared with those with ITDI less than 15 minutes. The incidence of metabolic acidosis increases with increasing ITDI and there is a statistically significant increased risk of neonatal acidosis after longer than 60 minutes compared with less than 15 minutes of ITDI.

Effect of inter-twin delivery interval on neonatal haemoglobin concentration

SummaryThe aim of this study was to examine the effect of the inter-twin delivery interval on neonatal haemoglobin concentration. We retrospectively analysed 108 twin deliveries over a 5-year period. Chorionicity was determined by first trimester ultrasound or placental histopathology. The mode of delivery, time of delivery and cord/neonatal blood counts were recorded. A total of 88 sets of dichorionic and 20 sets of monochorionic twins were studied. There was no correlation between inter-twin delivery interval and haemoglobin difference (rho = 0.020, p = 0.857). In monochorionic twin pregnancies, there was a trend towards increasing inter-twin hemoglobin differences with prolonged delivery intervals. However, this trend did not reach statistical significance (rho = −0.303, p = 0.193). In monochorionic twins, there is a trend towards a lower haemoglobin concentration in the twin delivered second. This haemoglobin deficit appears to be related to the inter-twin delivery interval.

The relationship between inter-twin delivery interval and metabolic acidosis in the second twin

To investigate the relationship between inter-twin delivery interval (ITDI) and metabolic acidosis in the second twin at birth. Retrospective cohort study in a tertiary-level teaching hospital. Twins with birth weights > 750g and vaginal delivery of the first baby were identified from an obstetrical database over a 10 year period. Mean arterial cord pH, and base deficit among different ITDI were calculated by analysis of variance. Logistic regression models were used to estimate effects of ITDI on metabolic acidosis. The main outcome measure was the incidence of metabolic acidosis in the second twin (defined as pH < 7.0 and base deficit > 12 mmol/L) at different ITDI. 310 twin pairs met the inclusion criteria. Second twin mean pH was significantly lower and base deficit significantly higher when ITDI exceeded 60 minutes. The incidence of metabolic acidosis increased with increasing ITDI (chi square test for linear trend p=0.02) and at > 60minutes there was a substantially greater proportion (3/9) of acidotic neonates when compared to ITDI of < 15 minutes [OR=22.6 (95%CI 2.5, 494.1)] An ITDI of 60 minutes is a reasonable time threshold at which to consider operative delivery. The application of such a policy for the 8% of second twins in our population, who exceeded this 60 minute interval, could result in a 33% reduction in the number of babies exposed to the potentially damaging effects of metabolic acidosis.