Acute twin-twin transfusion syndrome in labor: pathophysiology and associated factors

Multiple Pregnancy and the Risk of Postpartum Hemorrhage: Retrospective Analysis in a Tertiary Level Center of Care

The aim of our study was to identify characteristics associated with postpartum hemorrhage (PPH defined as blood loss >1000 mL) in twin pregnancies in order to select patients at higher risk to be treated. This retrospective study includes multiple pregnancies between 2015 and 2020. The possible association between pregnancy characteristics and the primary endpoint (occurrence of PPH) was conducted using chi-square or Fisher exact test and Wilcoxon test. Then, univariate logistic models were performed considering as outcome the PPH, and the odds ratios with 95% CI were estimated. Finally, a multivariate logistic model was implemented, including all significant covariates. Seven hundred seven twin pregnancies giving birth beyond 32 weeks were included and of those, 120 (16.97%) had a PPH. The univariate analysis showed that factors significantly associated with PPH were: Preterm delivery, episiotomy, neonatal weight, and mode of delivery. The multivariate analysis showed that the most important factors were episiotomy and neonatal weight. The results show that the performance of episiotomy and the neonatal weight are the factors that most impact the risk of PPH in twin pregnancies. The correct identification of factors associated with PPH in twins could ideally allow to modify the clinical management and positively affect the rate of complications.

What is the success rate of trial of labor in monochorionic diamniotic twins? A systematic review and meta-analysis of observational studies

OBJECTIVE

This meta-analysis aimed to evaluate the success rate of trial of labor in monochorionic diamniotic pregnancies and the impact of delivery mode on neonatal outcomes.

DATA SOURCES

Searches were performed in MEDLINE/PubMed, Embase, Scopus, Cochrane Central Register of Controlled Trials, ClinicalTrials.gov, and the International Clinical Trials Registry Platform from the inception of each database until April 2022.

STUDY ELIGIBILITY CRITERIA

Selection criteria included observational studies analyzing the delivery mode among monochorionic diamniotic gestations.

METHODS

All analyses were carried out using an intention-to-treat approach, evaluating women according to the delivery mode to which they were assigned in the original studies.

RESULTS

Seventeen studies met the eligibility criteria and were suitable for qualitative and quantitative analysis. In total, 4116 women were analyzed. This meta-analysis showed that trial of labor in monochorionic diamniotic pregnancies resulted in vaginal delivery of both twins in 75.5% of cases (95% confidence interval, 69.1-80.9). Failure to deliver the second twin vaginally occurred in 3.8% of cases (95% confidence interval, 2.5-5.7). In addition, the neonatal outcomes were comparable among women with monochorionic diamniotic pregnancy undergoing different planned delivery modes. Neonatal death occurred in 3.7 per 1000 cases in the planned cesarean delivery group and in 1.6 per 1000 cases in the planned vaginal delivery group. Perinatal death was observed in 7.5 per 1000 cases in the planned cesarean delivery group and in 5.8 per 1000 cases in the planned vaginal delivery group. Umbilical artery pH <7.00 occurred in 0 per 1000 cases in the planned cesarean delivery and 4.6 per 1000 cases in the planned vaginal delivery group. Neonatal intensive care unit stay of >72 hours had a prevalence of 59.7 per 1000 cases in the planned cesarean delivery and 42.8 per 1000 cases in the planned vaginal delivery group.

CONCLUSION

This meta-analysis showed that trial of labor in monochorionic diamniotic pregnancies is successful in most cases and relatively safe, considering that neonatal and perinatal mortality and severe morbidity were comparable between the trial of labor and planned cesarean delivery groups. Therefore, the choice of planned delivery mode in twin gestations should not be made a priori.

Acute Twin-to-Twin Transfusion Syndrome Resulting in Fetal Bradycardia and Neonatal Death: A Case Report

In monochorionic twins with no evidence of chronic twin-to-twin transfusion syndrome or twin anemia-polycythemia sequence, a sudden onset of fetal transfusion syndrome after the second trimester of pregnancy is defined as acute twin-to-twin transfusion syndrome. Labor pain, change in the fetal position, and birth order are known risk factors for this condition, and the hemoglobin level of the donor twin is usually reported to be <12 g/dL. We report a recent case of acute twin-to-twin transfusion syndrome without effective labor pain causing cervical changes, resulting in fetal bradycardia and neonatal death after birth; however, the anemia of the donor twin was not as severe as has been reported previously in twin-to-twin transfusion syndrome cases.

Placental characteristics of selective intrauterine growth restriction with changing patterns in umbilical artery Doppler flow in monochorionic diamniotic twins

OBJECTIVES

To compare the placental features between selective intrauterine growth restriction (sIUGR) patients, with dynamic classification (DC) and stable classifications (SC).

METHODS

A cohort study was conducted from 1st April 2013 to 1st April 2020, we recruited sIUGR patients who had delivered at our center and examined placental characteristics with dye injection. The primary outcome was placental characteristics.

RESULTS

The prevalence of large artery-artery anastomosis (AAA) was significantly higher in sIUGR with DC than sIUGR with SC (88.2 vs. 46.6%, p=0.001). The total diameter of AAA was significantly larger in sIUGR with DC than sIUGR with SC [2.9 (1.4, 7.0) vs. 2.4 (0.3, 7.1) mm, p=0.032]. The total number of artery-vein anastomosis was significantly smaller in sIUGR with DC than sIUGR with SC [3 (1, 12) vs. 5 (1, 15), p=0.023]. The incidence of neonatal asphyxias of growth-restricted fetuses were higher in sIUGR with DC than sIUGR with SC (23.5 vs. 5.9%, p=0.033).

CONCLUSIONS

Large AAA is probably associated to sIUGR with dynamic classification.

Twin to twin transfusion syndrome

Twin to twin transfusion syndrome (TTTS) is a common complication that typically presents in the second trimester of pregnancy in 10-15% of monochorionic twins due to net transfer of volume and hormonal substances from one twin to the other across vascular anastomoses on the placenta. Without recognition and treatment, TTTS is the greatest contributor to fetal loss prior to viability in 90-100% of advanced cases. Ultrasound diagnosis of monochorionicity is most reliable in the first trimester and sets the monitoring strategy for this type of twins. The diagnosis of TTTS is made by ultrasound with the findings of polyhydramnios due to volume overload and polyuria in one twin and oligohydramnios due to oliguria of the co-twin. Assessment of bladder filling as well as arterial and venous Doppler patterns are required for staging disease severity. Assessment of fetal cardiac function also provides additional insight into the fetal cardiovascular impacts of the disease as well as help identify fetuses that may require postnatal follow up. Fetoscopic laser ablation of the communicating vascular anastomoses between the twins is the standard treatment for TTTS. It aims to cure the condition by interrupting the link between their circulations and making them independent of one another. Contemporary outcome data after laser surgery suggests survival for both fetuses can be anticipated in up to 65% of cases and survival of a single fetus in up to 88% of cases. However, preterm birth remains a significant contributor to postnatal morbidity and mortality. Long term outcomes of TTTS survivors indicate that up to 11% of children may show signs of neurologic impairment. Strategies to minimize preterm birth after treatment and standardized reporting by laser centers are important considerations to improve overall outcomes and understand the long-term impacts of TTTS.

Effect of twin pregnancy chorionic properties on maternal and fetal outcomes

OBJECTIVE

This study aimed to determine the effect of twin pregnancy chorionic properties on pregnancy complications and fetal outcomes.

MATERIALS AND METHODS

A total of 559 subjects with gemellary pregnancy were included in the retrospective analysis, and clinical data, such as monitoring data during pregnancy and maternal and fetal outcomes, were recorded in detail. Based on the ultrasound results and methods of the postpartum pathologic examination of the placental membranes, the subjects were divided into the twin group with monochorionic diamnion (MCDA group, n = 198) and twin group with dichorionic diamnion (DCDA group, n = 361). The relationships of different chorionic properties and maternal and fetal outcomes were determined by comparing the maternal complications and fetal outcomes.

RESULTS

The occurrence rate of gemellary pregnancy was 2.97% and that of monochorionic twin pregnancy was 34.8%. The MCDA group showed a higher incidence of pregnancy-induced hypertension, gestational diabetes mellitus, polyhydramnios, premature rupture of membranes, and abruptio placenta and a lower incidence of severe postpartum hemorrhage than the DCDA group. However, the incidence of preterm birth was significantly different (57.6% vs. 45.7%, P < 0.05). Significant differences were also detected in the incidence of fetal loss, complicated twins, neonatal asphyxia, and perinatal death between the two groups (P < 0.05).

CONCLUSION

The incidence of maternal complication (such as pregnancy-induced hypertension, gestational diabetes mellitus, polyhydramnios, premature rupture of membranes, and abruptio placenta and severe postpartum hemorrhage) in the two groups was not significantly different; however, the fetal outcomes in the MCDA group were inferior to those in the DCDA group. The fetal outcomes may be improved by determining the chorionic properties in early pregnancy by using ultrasound and consequently planning for pregnancy monitoring and intervention.

Future Directions in the Management of Twin-to-Twin Transfusion Syndrome

Twin-to-twin transfusion syndrome (TTTS) is the major complication of monochorionic (MC) pregnancy. The outcomes of this condition have been significantly improved after the introduction and widespread uptake of fetoscopic laser ablation over the last decade. However, there is still a significant fetal loss rate and morbidity associated with this condition. Improvements in the management of TTTS will require improvements in many areas. They are likely to involve refinements in the prediction of the disease and clarification of the optimum frequency of surveillance and monitoring. Improvements in training for fetoscopic surgery as well as in the technique of fetoscopic laser ablation may lead to better outcomes. New technologies as well as a better understanding of the pathophysiology of TTTS may lead to adjuvant medical therapies that may also improve short- and long-term results.

The North American Fetal Therapy Network Consensus Statement: prenatal management of uncomplicated monochorionic gestations

Owing to vascular connections within a single placenta, monochorionic gestations present distinctive prenatal management challenges. Complications that can arise as a result of unbalanced hemodynamic exchange (twin-twin transfusion syndrome and twin anemia polycythemia sequence) and unequal placental sharing (selective fetal growth restriction) should be kept in mind while prenatal management is being planned. Because of unique monochorionic angioarchitecture, what happens to one twin can directly affect the other. Death of one twin can result in death or permanent disability of the co-twin. Early detection of these unique disease processes through frequent ultrasonographic surveillance may allow the opportunity for earlier referral, intervention, or both and potentially better outcomes. Therefore, monochorionic gestations should be managed differently than dichorionic gestations or singletons. The purpose of this document is to present in detail methods for monitoring and management of uncomplicated monochorionic gestations and to review the evidence for the roles of these methods for detection of complications in clinical practice. Finally, we present evidence-based and expert opinion-supported recommendations developed by the North American Fetal Therapy Network for the diagnosis, surveillance, and delivery of uncomplicated monochorionic gestations.

Association of prelabor cesarean delivery with reduced mortality in twins born near term

OBJECTIVE

To examine short-term and longer-term outcomes for twins born at or near term, comparing prelabor cesarean delivery with birth after a trial of labor.

METHODS

This study was conducted on a retrospective cohort of twin pregnancies delivered at 36 weeks of gestation or greater from 2000 to 2009. Pregnancies with an antenatal death, lethal anomaly, birth weight discordance 25% or more, or birth weight less than 2,000 g or more than 4,000 g were excluded. Outcomes included severe hypoxia, stillbirth and neonatal death, and hospital admissions or death during the first 5 years of life.

RESULTS

Approximately 45% of 7,099 twin pregnancies were delivered by prelabor cesarean delivery. Compared with delivery after labor, prelabor cesarean delivery was associated with significantly reduced risks of adverse neonatal and child outcomes including severe birth hypoxia (0.08% compared with 0.75%, relative risk 0.10, 95% confidence interval [CI] 0.04-0.26), neonatal death (0.00% compared with 0.15%, relative risk 0.05, 95% CI 0.00-0.82), and death up to 5 years of age (0.16% compared with 0.40%, relative risk 0.41, 95% CI 0.20-0.85). Whereas total mortality for first twins was similar after labor (0.15%) compared with prelabor cesarean delivery (0.16%), total mortality was four times more common in second twins born after labor (0.64%) compared with second twins born after prelabor cesarean delivery (0.16%).

CONCLUSION

Compared with prelabor cesarean delivery, twin pregnancies at and beyond 36 weeks of gestation delivered after labor have increased risks for birth outcomes associated with hypoxia, with second twins having significantly increased mortality up to 5 years of age. However, the absolute mortality rate for relatively uncomplicated twin pregnancies delivered at or near term is low and needs to be balanced against maternal morbidity.

LEVEL OF EVIDENCE

II.

Clinical characteristics of monochorionic twins with large hemoglobin level discordance at birth

OBJECTIVES

To evaluate neonatal outcomes and clinical characteristics of monochorionic diamniotic (MCDA) twins with a large intertwin hemoglobin (Hb) difference at birth.

METHODS

This was a retrospective cohort study of MCDA twin gestations delivered at Osaka Medical Center and Research Institute for Maternal and Child Health between 2003 and 2012. Cases of pregnancy termination, acardiac twins or intrauterine death were excluded. A large intertwin Hb difference at birth was defined as > 8.0 g/dL according to the postnatal criteria for twin anemia-polycythemia sequence (TAPS). The intertwin reticulocyte count ratio (RCR) was calculated by dividing the reticulocyte count of the anemic twin by that of the polycythemic twin. Cases with Hb differences were divided into two groups according to the RCR, TAPS when the RCR was > 1.7 and acute fetofetal hemorrhage (AFFH) when the RCR was ≤ 1.7. Neonatal outcomes were compared between the TAPS and AFFH groups.

RESULTS

During the study period, 432 MCDA twin pregnancies of a total of 532 born at our hospital were analyzed. There were 12 (2.8%) cases of a large intertwin Hb difference. The median gestational age at birth of these cases was 34 (range, 23-38) weeks, and all were delivered by Cesarean section. There were seven (1.6%) cases of TAPS and five (1.2%) of AFFH. The neonatal survival rate was 91.7%; in one pair of twins with TAPS neonatal death occurred. All (100%) cases with TAPS and two (40%) with AFFH required blood transfusion or partial-exchange transfusion for at least one infant.

CONCLUSIONS

Although the incidence of TAPS and AFFH may be low in MCDA twins, many affected neonates required treatment for hematological abnormalities. Delivery of MCDA twins via Cesarean section does not appear to prevent AFFH, despite the absence of labor.

Acute peripartum twin-twin transfusion syndrome: incidence, risk factors, placental characteristics and neonatal outcome

AIM

The aim of this study was to examine the incidence, placental characteristics and outcome in acute peripartum twin-twin transfusion syndrome (TTTS).

MATERIAL AND METHODS

All consecutive cases of monochorionic (MC) twins admitted to our center were included in the study. We excluded cases with chronic TTTS or twin anemia polycythemia sequence. Acute peripartum TTTS was defined when the inter-twin hemoglobin difference at birth was >8 g/dL.

RESULTS

A total of 241 MC twin pregnancies were included in the study. Acute peripartum TTTS was detected in six cases (2.5%, 6/241). Vaginal delivery occurred more often in the acute peripartum TTTS group compared to the control group of uncomplicated MC pregnancies, 100% (6/6) versus 57% (135/235) (P = 0.002), respectively. Acute anemia was detected only in firstborn twins. Placental angioarchitecture in acute peripartum TTTS was similar to the placentas in the control group.

CONCLUSIONS

The incidence of acute peripartum TTTS is low (2.5%). Birth order and mode of delivery appear to be associated with increased risk of acute peripartum TTTS.

What-and why-the pathologist should know about twin-to-twin transfusion syndrome

Approximately 20% of all twin pregnancies are monochorionic. Between 9% and 15% of all monochorionic twin gestations are complicated by severe chronic twin-to-twin transfusion syndrome (TTTS), characterized by a gradual shift of blood volume from the donor twin to the recipient twin through placental vascular connections [1 - 3] . The prognosis of severe, untreated chronic TTTS diagnosed in midtrimester fetuses is extremely poor, with mortality rates exceeding 70% [4] . Since publication of the results of the Eurofoetus trial in 2004, laser photocoagulation of the intertwin anastomoses has become accepted as the optimal first-line therapy for severe TTTS diagnosed before 26 weeks of gestation. While laser treatment of vascular communications was initially limited to selected fetal treatment centers, its increasingly widespread use has resulted in the exposure of more pathologists, even in less specialized institutions, to laser-treated placentas. Furthermore, the surge in laser coagulation has revived the general medical, scientific, and public interest in the placental and choriovascular findings in monochorionic twin placentas. The pathologist's understanding of the pathophysiology of TTTS and of TTTS-associated placental pathology, including the findings related to laser ablation of the anastomoses, can be of great benefit to the involved obstetric/neonatal/surgical team and, ultimately, to the patients. In this review, we summarize the current knowledge of the placental contributions to TTTS and other complications of monochorionic twinning and describe the strengths and limitations of placental examination in these settings. It is our expectation that overviews such as this may serve as a template to generate consensus guidelines for standardized and evidence-based pathologic evaluation of monochorionic twin placentas.