The consequences of monochorionic placentation

Interventions for the treatment of twin-twin transfusion syndrome

BACKGROUND

Twin-twin transfusion syndrome, a condition affecting monochorionic twin pregnancies, is associated with a high risk of perinatal mortality and morbidity. A number of treatments have been introduced to treat the condition but it is unclear which intervention improves maternal and fetal outcome.

OBJECTIVES

The objective of this review was to evaluate the impact of treatment modalities in twin-twin transfusion syndrome.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 May 2013).

SELECTION CRITERIA

Randomised and quasi-randomised studies of amnioreduction versus laser coagulation, septostomy versus laser coagulation or septostomy versus amnioreduction.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed eligibility and extracted data. We contacted study authors for additional information.

MAIN RESULTS

Three studies (253 women and 506 babies) were included. All three trials were judged to be of moderate quality. One study compared amnioreduction with septostomy (71 women), whilst the other two studies compared amnioreduction with endoscopic laser coagulation (182 women). Not all trials provided outcome data that could be included in all meta-analyses. Amnioreduction compared with laser coagulation Although there was no difference in overall death between amnioreduction and laser coagulation (average risk ratio (RR) 0.87; 95% confidence interval (CI) 0.55 to 1.38 adjusted for clustering, two trials) or death of at least one infant per pregnancy (RR 0.91; 95% CI 0.75 to 1.09, two trials), or death of both infants per pregnancy (average RR 0.76; 95% 0.27 to 2.10, two trials), more babies were alive without neurological abnormality at the age of six years in the laser group than in the amnioreduction groups (RR 1.57; 95% CI 1.05 to 2.34 adjusted for clustering, one trial). There were no significant differences in the babies alive at six years with major neurological abnormality treated by laser coagulation or amnioreduction (RR 0.97; 95% CI 0.34 to 2.77 adjusted for clustering, one trial). Outcomes for death in this 2013 update are different from the previous 2008 update, where improvements in perinatal death and death of both infants per pregnancy were shown in the laser intervention arm. The NIHCD trial included in this update exerts an opposite direction of effects to the Eurofetus study, which was previously the only included laser study, hence the difference in outcome. Amnioreduction compared with septostomy There are no differences in overall death (RR 0.83; 95% CI 0.47 to 1.47, adjusted for clustering, one trial), death of at least one infant per pregnancy (RR 0.80; 95% CI 0.48 to 1.35, one trial), or death of both infants per pregnancy (RR 0.90; 95% CI 0.37 to 2.22, one trial) or gestational age at birth (RR 1.20; 95% CI -0.81 to 3.21, one trial) between amnioreduction and septostomy.

AUTHORS' CONCLUSIONS

Endoscopic laser coagulation of anastomotic vessels should continue to be considered in the treatment of all stages of twin-twin transfusion syndrome to improve neurodevelopmental outcomes.Further research targeted towards assessing the effect of treatment on milder (Quintero stage 1 and 2) and more severe (Quintero stage 4) forms of twin-twin transfusion syndrome is required. Studies should aim to assess long-term outcomes of survivors.

Interventions for the treatment of twin-twin transfusion syndrome

BACKGROUND

Twin-twin transfusion syndrome, a condition affecting monochorionic twin pregnancies, is associated with a high risk of perinatal mortality and morbidity. A number of treatments have been introduced to treat the condition but it is unclear which intervention improves maternal and fetal outcome.

OBJECTIVES

The objective of this review was to evaluate the impact of treatment modalities in twin-twin transfusion syndrome.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (October 2007) and the Cochrane Central Register of Controlled Trials (The Cochrane Library 2007, Issue 4). We also searched conference proceedings and made personal contact with experts active in the area of the review.

SELECTION CRITERIA

Randomised and quasi-randomised studies of amnioreduction versus laser coagulation, septostomy versus laser coagulation or septostomy versus amnioreduction.

DATA COLLECTION AND ANALYSIS

One review author assessed eligibility and extracted data, which were checked by a second author. We contacted study authors for additional information.

MAIN RESULTS

Two studies (213 women) were included. This review shows that laser coagulation of anastomotic vessels results in less death of both infants per pregnancy (relative risk (RR) 0.33; 95% confidence interval (CI) 0.16 to 0.67, one trial), less perinatal death (RR 0.59; 95% CI 0.0.40 to 0.87 adjusted for cluster, one trial) and less neonatal death (RR 0.29; 95% CI 0.14 to 0.61 adjusted for cluster, one trial) than in pregnancies treated with amnioreduction. There is no difference in perinatal outcome between amnioreduction and septostomy. A third study is awaiting assessment. More babies were alive without neurological abnormality at the age of six months in the laser group than the amnioreduction groups (RR 1.66; 95% CI 1.17 to 2.35 adjusted for clustering, one trial). This difference did not persist beyond six months of age. There was no significant difference in the babies alive at six months with neurological abnormality treated by laser coagulation or amnioreduction (RR 0.58; 95% CI 0.18 to 1.86 adjusted for clustering, one trial).

AUTHORS' CONCLUSIONS

Endoscopic laser coagulation of anastomotic vessels should be considered in the treatment of all stages of twin-twin transfusion syndrome to improve perinatal outcome. Further research on the effect of treatment on milder forms of twin-twin transfusion syndrome (Quintero stage 1 and 2) are required. The long-term outcomes of survivors from the studies included in this review are required.

Best practice no 178. Examination of the human placenta

The human placenta is an underexamined organ. The clinical indications for placental examination have no gold standards. There is also inconsistency in the histological reports and the quality is variable. There is great interobserver variability concerning the different entities. Although there are still grey areas in clinicopathological associations, a few mainstream observations have now been clarified. The histopathological examination and diagnosis of the placenta may provide crucial information. It is possible to highlight treatable maternal conditions and identify placental or fetal conditions that can be recurrent or inherited. To achieve optimal benefit from placental reports, it is essential to standardise the method of placenta examination. This article summarises the clinical indications for placenta referral and the most common acknowledged clinicopathological correlations.

Influence of twin-twin transfusion syndrome on fetal cardiovascular structure and function: prospective case-control study of 136 monochorionic twin pregnancies

OBJECTIVE

To test the hypothesis that identical twins show no inter-twin differences in cardiovascular structure or physiology in fetal life unless there has been twin-twin transfusion syndrome.

DESIGN

Unselected prospective case-control observational study of fetoplacental haemodynamics including echocardiography at a median of 24 (16.7 to 32.3) weeks, with postnatal confirmation of congenital heart disease or normality.

SETTING

Fetal medicine unit.

PATIENTS

136 women with monochorionic diamniotic twin pregnancies, of which 47 fetal twin pairs (35%) had twin-twin transfusion syndrome.

RESULTS

There were no haemodynamic differences between the bigger fetus (twin 1) and the smaller co-twin (twin 2) in uncomplicated monochorionic diamniotic pairs. In twin-twin transfusion syndrome, recipient fetuses had increased aortic and pulmonary velocities compared with their donor co-twins (mean (SD): 0.73 (0.23) m/s and 0.63 (0.14) m/s), respectively, v 0.53 (0.16) m/s and 0.48 (0.10) m/s in donor twins; p = 0.003 (aortic) and < 0.0001 (pulmonary)), and also in comparison with twin 1 and twin 2. The overall prevalence of congenital heart disease was increased above that in singletons (3.8% v 0.56%; 6.9% in twin-twin transfusion v 2.3% in uncomplicated monochorionic diamniotic twins), with inter-twin discordance for defects. The prevalence in recipient twins was 11.9% (p = 0.014 v uncomplicated control twins).

CONCLUSIONS

Fetuses with an identical genome but no circulatory imbalance have similar cardiovascular physiology but discordant phenotypic expression of congenital heart disease. The high prevalence of congenital heart disease in monochorionic diamniotic twins merits detailed fetal echocardiography.

Interventions for the treatment of twin-twin transfusion syndrome

BACKGROUND

Twin-twin transfusion syndrome, a condition affecting monochorionic twin pregnancies, is associated with a high risk of perinatal mortality and morbidity. A number of treatments have been introduced to treat the condition but it is unclear which intervention improves maternal and fetal outcome.

OBJECTIVES

The objective of this review was to evaluate the impact of treatment modalities in twin-twin transfusion syndrome.

SEARCH STRATEGY

We searched The Cochrane Pregnancy and Childbirth Trials Register and Cochrane Controlled Trials Register. We also searched conference proceedings and made personal contact with experts active in the area of the review. Date of last search: August 2000.

SELECTION CRITERIA

Randomised and quasi-randomised studies of amnioreduction versus laser coagulation, septostomy versus laser coagulation or septostomy versus amnioreduction.

DATA COLLECTION AND ANALYSIS

Eligibility was assessed by one reviewer. Study authors were contacted for additional information.

MAIN RESULTS

No studies were included.

REVIEWER'S CONCLUSIONS

There is no current evidence from randomised trials to influence practice. Three ongoing randomised studies have been identified.

Low birthweight and metabolic abnormalities in twins with increased susceptibility to Type 2 diabetes mellitus

AIMS

To evaluate the role of environmental intra-uterine factors in determining the birthweights of twins with increased susceptibility to diabetes and discordant for abnormal responses to the oral glucose tolerance test (OGTT) and verify the possible association of within-pair birthweight differences and metabolic abnormalities in adult life.

METHODS

Forty-six monozygotic (MZ) and 32 dizygotic (DZ) twins were enrolled; 13 MZ twins were discordant for impaired glucose tolerance (IGT) and/or hyperinsulinaemia compared to their co-twins.

RESULTS

The 13 MZ discordant twins showed significantly lower birthweights than their normal co-twins (P < 0.001). When dividing all twins in those with the highest birthweights within the couple and those with the lowest, all subjects with abnormal OGTT were found in the latter group (P < 0.0001). Within-pair birthweight difference was significantly higher in MZ twins with abnormal OGTT and the metabolic syndrome compared to normal MZ twins. The relative risk of developing the metabolic syndrome was 8.7 (1.6-46.9) when comparing the higher tertile of within-pair birthweight differences (> or = 0.450 kg) to the two lower tertiles (< 0.450 kg). Logistic regression analysis confirmed within-pair birthweight difference as a significant predictor of abnormal responses to the OGTT and the metabolic syndrome.

CONCLUSIONS

These data suggest a causative role for environmental intrauterine factors on the determination of birthweight and support the hypothesis that within-pair birthweight difference, rather than an absolute low birthweight, is responsible for the metabolic abnormalities in the adult life.