Twin-twin Transfusion Syndrome Group Research Articles

Long-Term Neurodevelopmental Outcome After Selective Fetoscopic Laser Therapy for Stage I Twin-Twin Transfusion Syndrome.

Twin-twin transfusion syndrome (TTTS) is a serious complication in monochorionic (MC) pregnancies. Fetoscopic laser surgery (FLS) is the primary treatment for advanced TTTS, but managing Quintero stage I TTTS is still controversial. We conducted an observational study evaluating the 2-year neurodevelopment of fetuses, which underwent FLS for stage I TTTS, compared with advanced TTTS and uncomplicated monochorionic diamniotic twins (MCDTs). The study included 156 children: 14 in stage I TTTS group, 28 in advanced TTTS group, and 114 in uncomplicated twin group. In stage I TTTS, 92.9% showed normal neurodevelopment, with no severe neurological impairments observed. These results were comparable with uncomplicated twins (92.1% normal neurodevelopment, P = .921, adjusted odds ratio [aOR] = 1.56, 95% confidence interval [CI] = 0.42-5.79; 1.8% severe impairment, P = .617). Advanced TTTS had a non-significant lower rate of normal neurodevelopment (89.3%, P = .710, aOR = 1.31, 95% CI = 0.12-14.87). In conclusion, FLS for stage I TTTS shows favorable long-term neurodevelopmental outcomes, similar to uncomplicated MC pregnancies.

Two Year Neurodevelopmental Outcome after Fetoscopic Laser Therapy for Twin-Twin Transfusion Syndrome: Comparison with Uncomplicated Monochorionic Diamniotic Twins.

Twin-twin Transfusion Syndrome (TTTS) represents a significant complication in monochorionic twin pregnancies, caused by an unbalanced shunting of blood through intertwin placental vascular anastomoses. Despite advances in fetoscopic laser surgery, TTTS is still associated with a high rate of cerebral injury. However, there are no studies comparing these pregnancies with uncomplicated monochorionic diamniotic (MCDA) twin pregnancies, establishing the baseline risk of neurodevelopmental impairment. The aim of this study is to evaluate the odds of neurodevelopmental impairment in MCDA twins who undergo fetoscopic laser surgery for twin-twin transfusion syndrome, in comparison to a cohort of uncomplicated MCDA twin pregnancies. This is a retrospective cohort study of children born from MCDA twin pregnancies at a single center between 2008 and 2019. A routine, standardized follow-up assessment was conducted at a minimum of 2 years after delivery. The primary outcome of this was a 2 year neurodevelopmental impairment. Neurological, motor, and cognitive development was assessed by using the revised Brunet-Lézine scale. 176 children met the enrolment criteria. Of these, 42 (24%; TTTS group) underwent fetoscopic laser surgery for TTTS during pregnancy, and 134 (76%; uncomplicated MCDA group) were uncomplicated MCDA pregnancies. The primary outcome was found in four children (9.52%) in the TTTS group and ten children (7.46%) in the uncomplicated MCDA group (p = 0.67, aOR 2.82, 95% CI 0.49-16.23). Major neurologic impairment was found in 2.38% after fetoscopic laser surgery and 1.49% in uncomplicated MCDA twins (p = 0.70, aOR 0.97, 95% CI 0.22-4.24). The data were adjusted by birth order, birth weight, and gestational age at birth. The outcome in MCDA twins who underwent fetoscopic laser surgery for TTTS is comparable to the outcome in uncomplicated MCDA twins. Our findings emphasize the need for long-term neurodevelopmental follow-ups in all children from monochorionic twin gestations.

Twin twin transfusion syndrome with and without selective fetal growth restriction: Predictors of donor demise.

Evaluate survival in twin twin transfusion syndrome (TTTS) with and without selective fetal growth restriction (sFGR) after fetoscopic laser surgery (FLS). Retrospective study of monochorionic diamniotic twins undergoing FLS. The cohort was classified as TTTS and TTTS with sFGR. Baseline, intra-operative and postoperative variables were analyzed. Mann-Whitney U, Pearson chi-square, Fisher's exact, t-test and receiver operating characteristic (ROC) curve analysis were performed. Four hundred and ninety-two pregnancies were included, 304 (61.78%) TTTS and 188 (38.22%) TTTS with sFGR. No difference in donor outcomes. TTTS group had higher donor estimated fetal weight (EFW%) percentile (19.7±18.8 vs. 2.2±2.1, p<0.001). Significant predictors for demise at 30days were 37% intertwin weight discordance (IWD) with donor EFW%<first (area under ROC curve [AUC]=0.85, p=0.001) or IWD >25% and intertwin umbilical artery pulsatility index discordance (DUAPI) ≥0.4 (AUC=0.71, p=0.001). Combination of IWD of 37% and donor EFW% <first was most predictive for demise 30days after birth. DUAPI ≥0.4 was also associated with increased risk for demise.

The role of umbilical artery velocities in the clinical assessment of twin-twin transfusion syndrome at stage.

To analyze the discordances of the umbilical artery velocities between pregnancies with twin-twin transfusion syndrome (TTTS) at stage I and those with normal monochorionic-diamniotic (MCDA) twins, and investigate the value of their discordances in predicting TTTS at stage I. We recruited 58 twin pregnancies with TTTS at stage I and 60 normal MCDA twin pregnancies in a tertiary referral center retrospectively. The umbilical artery velocities and their discordances were compared between the normal and TTTS twins. The discordances of umbilical artery mean diastolic velocity (UA-MDV), umbilical artery time-averaged maximum velocity (UA-TAmax), umbilical artery peak systolic velocity (UA-PSV), and umbilical artery end-diastolic velocity (UA-EDV) were higher in the TTTS group than in the normal group. In TTTS co-twins, the UA-MDV, UA-TAmax, UA-PSV, and UA-EDV in recipients were higher than those in donors. The discordances of UA-TAmax and UA-PSV were found to be independent predicting factors for TTTS at stage I. Co-twin umbilical artery velocity discordances were significantly associated with stage I TTTS. The results suggest that UA-TAmax and UA-PSV might be new parameters for predicting TTTS at stage I.

Influence of indications on perinatal outcomes after radio frequency ablation in complicated monochorionic pregnancies: a retrospective cohort study

BackgroundRadiofrequency ablation (RFA) is recommended to prevent potential neurological injury or intrauterine foetal death (IUFD) of the co-twin(s) in complicated monochorionic (MC) pregnancies. However, the impacts of various indications on the pregnancy outcome following RFA remain unclear. This study aimed to determine how the indications influence the perinatal outcomes in complicated MC pregnancies undergoing radiofrequency ablation.MethodsThis was a retrospective cohort study performed in a single centre. All consecutive MC pregnancies treated with RFA between July 2011 and July 2019 were included. The adverse perinatal outcomes and the survival rate were analysed based on various indications. The continuous variables with and without normal distribution were compared between the groups using Student’s t-test and Mann–Whitney U test, respectively, and for categorical variables, Chi-square and Fisher’s exact tests were used. P < 0.05 indicated a significant difference.ResultsWe performed 272 RFA procedures in 268 complicated MC pregnancies, including 60 selective intrauterine growth restriction (sIUGR), 64 twin–twin transfusion syndrome (TTTS), 12 twin reversed arterial perfusion sequence (TRAPs), 66 foetal anomaly and 66 elective foetal reduction (EFR) cases. The overall survival rate of the co-twin was 201/272 (73.9%). The overall technical successful rate was determined at 201/263 (76.7%). The IUFD rate in the co-twin was 20/272 (7.4%). The TTTS group had recorded the lowest survival rate (37/64, 57. 8%), and the survival rate was significantly correlated with Quintero stages (P = 0.029). Moreover, the sIUGR III subgroup had a lower survival rate compared with sIUGR II (55.6%, versus 84.3%). The subgroup of foetal anomaly of gastroschisis or exomphalos had the highest IUFD rate (4/10, 40%), followed by sIUGR III (2/9, 22.2%) and dichorionic triamniotic (DCTA) subgroup (8/46, 17.9%). In EFR group, eight IUFD cases were all coming from the DCTA subgroup and received RFA before 17 weeks.ConclusionsThe perinatal outcome of RFA was correlated with the indications, with the lowest survival rate in TTTS IV and the highest IUFD incidence in abdominal wall defect followed by sIUGR III. Elective RFA after 17 weeks may prevent IUFD in DCTA pregnancies.

Predictive value of first-trimester ultrasound markers for complicated monochorionic diamniotic twins

Objective To investigate the value of first-trimester ultrasound parameters in predicting complicated monochorionic diamniotic (MCDA) twins. Methods In this retrospective study, pregnant women diagnosed as MCDA twins by ultrasound in the First Affiliated Hospital of Sun Yat-sen University from January 2013 to January 2018 were recruited and divided into the following four groups: non-complicated MCDA twins group, twin-twin transfusion syndrome (TTTS) group, selective intrauterine growth restriction (sIUGR) group and twin anemia-polycythemia sequence (TAPS) group. Thickness of nuchal translucency (NT), crown-rump length (CRL), umbilical cord insertion (UCI) and ductus venosus (DV) flow at 11-14 weeks of gestation were recorded. The predictive value for complicated MCDA twins was analyzed using t-test, Chi-square (or Fisher's exact) test, multivariate logistic regression analysis and receiver operating characteristic (ROC) curve. Results (1) A total of 430 MCDA twin pregnancies were included in this study with 152 in the TTTS group, 142 in the sIUGR group, seven in the TAPS group and 129 in the normal MCDA twins group. No further analysis was performed on the TAPS group due to the small sample size. (2) NT discordance in twins of the TTTS group was significantly greater than that in the normal MCDA twins group[(21.5±16.0)% vs (14.6±13.5)%, t=-3.533, P<0.001]. The area under ROC curve (AUC) of TTTS predicted by NT discordance was 0.649. Stratified analysis showed that TTTS was best predicted when NT discordance was 20% with the sensitivity of 57.9% and specificity of 70.6%. (3) The sIUGR group had greater discordance in CRL and NT and higher UCI discordance than the normal MCDA twins group [NT: (27.8±21.3)% vs (14.6±13.5)%, t=-5.556, P<0.001; CRL: (8.6±6.9)% vs (5.4±4.4)%, t=-3.144, P=0.002; UCI: 47.9% (68/142) vs 13.9% (18/129), χ2=35.929, P<0.001]. The AUC of sIUGR was 0.675 predicted by NT discordance and 0.649 by CRL discordance. Stratified analysis showed that NT discordance of 20% and CRL discordance of 10% were the best prediction for sIUGR with the sensitivity of 53.1% and 34.7% and specificity of 72.1% and 83.8%, respectively. Multivariate logistic regression analysis suggested that UCI discordance was the risk factor for sIUGR (OR=7.165, 95%CI: 2.637-19.472). Conclusions MCDA twins with NT discordance greater than 20% during early pregnancy are at increased risk for TTTS. CRL discordance greater than 10%, NT discordance greater than 20% and abnormal UCI are risk factors for sIUGR. Key words: Twins, monozygotic; Pregnancy trimester, first; Ultrasonography, prenatal; Nuchal translucency measurement; Fetofetal transfusion; Fetal growth retardation; Forecasting

MicroRNA changes in maternal serum from pregnancies complicated by twin-twin transfusion syndrome: A discovery study.

ObjectiveMicroRNAs (miRNAs) are used as biomarkers in cardiovascular disease and cancer. miRNAs are involved in placental development but have not previously been investigated in twin‐twin transfusion syndrome (TTTS). Our aim is to explore the miRNA profile of TTTS pregnancies.MethodInitial miRNA profiling was performed using a reverse transcription polymerase chain reaction (RT‐PCR) panel on maternal serum samples taken from five women prior to fetoscopic laser ablation for TTTS and compared with serum samples from five women with uncomplicated monochorionic diamniotic twin pregnancies. Validation RT‐PCR was performed in an additional cohort of eight TTTS pregnancies and eight uncomplicated pregnancies.ResultsMedian gestational age at sampling in the TTTS and control groups was 20+0 weeks (interquartile range [IQR], 19+4‐20+0) and 20+2 weeks (IQR, 20+0‐20+2), respectively. All samples passed quality control. One control sample was excluded as a biological outlier. Thirty‐one of 752 miRNAs were significantly different: 17 were upregulated and 14 downregulated in the TTTS group, although they did not remain significant following Benjamini‐Hochberg correction for multiple testing. The six miRNAs chosen for validation demonstrated no significant difference.ConclusionThis is the first study to investigate miRNA changes in TTTS pregnancies. We did not demonstrate a statistically significant difference in miRNAs in TTTS pregnancies, but further investigation is required.

Increased Risk Of Early-Onset Neonatal Sepsis After Laser Surgery For Twin-to-Twin Transfusion Syndrome.

To investigate the occurrence of early-onset neonatal sepsis (EOS) in twin-twin transfusion syndrome (TTTS) managed with laser surgery. We performed a prospective cohort study of all consecutive TTTS cases treated with laser surgery (TTTS group) delivered at the Leiden University Medical Center. We recorded the occurrence of EOS, defined as a positive blood culture ≤72 hours postpartum (proven sepsis) or administration of a full course of antibiotics due to risk factors or signs of sepsis, in the absence of a positive blood culture (suspected sepsis). Perinatal variables in the TTTS group were compared with uncomplicated monochorionic twins (no-TTTS group). A multivariate model was generated, examining the association between EOS and gestational age at birth, interval between laser surgery and birth, anterior placenta, laser period (first study period: 2002-2008; second study period: 2009-2015), and preterm premature rupture of membranes (PPROM). The rates of combined suspected and proven EOS in the TTTS group and no-TTTS group were 16% (68/416) and 10% (55/542), respectively (relative ratio [RR] 1.74, 95% confidence interval [CI] 1.19-2.55). Multivariate analysis showed that EOS in the TTTS group was independently associated with lower gestational age at birth (odds ratio [OR] 0.75, 95% CI 0.63-0.88), first study period (OR 2.25, 95% CI 1.08-4.67) and PPROM (OR 2.47, 95% CI 1.28-4.75). The rate of EOS in the TTTS group is low, but increased compared to the no-TTTS group. EOS in TTTS is independently associated with premature delivery, earlier laser period, and PPROM.

Velamentous cord insertion in dichorionic and monochorionic twin pregnancies – Does it make a difference?

ObjectiveTo estimate the prevalence of velamentous cord insertion (VCI) in dichorionic (DC) and monochorionic (MC) twins with and without twin-twin transfusion syndrome (TTTS), and to study the associated outcomes. MethodsWe recorded the type of umbilical cord insertion in all consecutive DC and MC placentas examined in two European tertiary medical centers. The association between VCI and perinatal outcomes was estimated and compared. ResultsA total of 1498 twin placentas were included in this study (DC placentas n = 550, MC placentas without TTTS n = 513 and MC placentas with TTTS n = 435). The prevalence of VCI in DC, MC without TTTS and MC with TTTS groups was 7.6%, 34.7% and 36.1%, respectively (P < 0.001). In MC twins (non-TTTS and TTTS groups), VCI was associated with severe birth weight discordance (odds ratio [OR] 4.76 95% CI 2.43, 10.47 and OR 4.52 95% CI 1.30, 28.59, respectively). In MC twins without TTTS, VCI was associated with small for gestational age (OR 1.66, 95% CI 1.12, 2.50). VCI was significantly associated with increased risk of intrauterine fetal demise in MC twins, and this effect was greater in the non-TTTS group (OR 2.71 95% CI 1.38, 5.47). These associations did not occur in DC group. Gestational age at birth was lower in the presence of VCI in the DC and MC twins without TTTS. ConclusionOur findings confirm that the prevalence of VCI is higher in MC twins than in DC twin pregnancies. VCI is an important indicator of adverse perinatal outcome, particularly in MC twins.

Twin-twin transfusion syndrome: neurodevelopment of infants treated with laser surgery.

To assess the neurodevelopmental functions of survivors of twin-twin transfusion syndrome (TTTS) treated by fetoscopic laser coagulation (FLC), during the first year of life, comparing them to a control group; and to verify the influence of specific variables on neurodevelopment. This was a prospective, longitudinal study. The sample comprised 33 monochorionic diamniotic twins who underwent FLC for treatment of TTTS and 22 full-term infants of single-fetus pregnancies. Bayley Scales of Infant and Toddler Development Screening Test were used for evaluation. Prenatal, perinatal and postnatal information were obtained. There was an increased frequency of infants in the TTTS group with inadequate performance compared to the control group. The identified variables (fetal donor, low economic income and cardiorespiratory disease) negatively impacted expressive communication and fine motor skills. Although through follow-up is recommended in all TTTS survivors, particular attention is required for the high-risk group as defined in this study.

Color-dye injection of monochorionic placentas and correlation with pregnancy complications

IntroductionVascular anastomoses in monochorionic (MC) twin placenta can be easily identified with color-dye injection. The aim of this study is to analyze the relationship between different type of anastomoses and twin pregnancy complications. MethodsFrom January 2011 to October 2014, MC placentas were analyzed with color-dye injection and five group of pregnancies were identified: those that were not complicated (NC), those complicated with selective intrauterine growth restriction (sIUGR), twin–twin transfusion syndrome (TTTS), or twin anemia-polycitemia sequence (TAPS) and those with amniotic fluid discordance (AFD) between twins. Cases of TTTS treated with endoscopic laser coagulation of placenta anastomoses or cases with in utero death of one twin were excluded. ResultsA total of 118 MC placentas were observed, 58 (49%) NC, 35 (30%) sIUGR, 10 (8%) TTTS, 13 (11%) AFD and 2 (2%) TAPS. The median number of anastomoses was 7 (range 1–15), 8 (2–18), 4 (2–11), 7 (2–13) and 1 (1–1), respectively. At least one artero-venous anastomoses was found in the placenta observed, while the prevalence of artero-arterial anastomoses was 95% for NC, 91% for sIUGR, 60% for TTTS, and 77% for AFD; no TAPS placenta had this type of anastomoses. The diameter of arteroarterial anastomoses was greater in the AFD group (3.3 mm), compared to the NC, sIUGR and TTTS groups (2.3, 2.5 and 1.4 respectively, p 0.04). DiscussionIn this large serie of MC placenta analyzed with color-dye injection, a specific distribution of anastomoses emerged for twins with amniotic fluid discordance, which points to a need for intensive surveillance.

Veno–venous anastomoses in twin–twin transfusion syndrome: A multicenter study

IntroductionThe aim of this study is to evaluate the prevalence of veno–venous (VV) anastomoses in a large cohort of monochorionic (MC) twin placentas with twin–twin transfusion syndrome (TTTS) compared to a control group of MC placentas without TTTS. MethodsAll TTTS placentas not treated with fetoscopic laser surgery (TTTS group) and examined at five international fetal therapy centers were included in this study and compared with a control group of MC placentas without TTTS (non-TTTS group). MC placentas were routinely injected with colored dye. We recorded the presence of VV and arterio-arterial (AA) anastomoses. ResultsA total of 414 MC placentas were included in this study (TTTS group, n = 106; non-TTTS group, n = 308). The prevalence of VV anastomoses was significantly higher in the TTTS group than in the non-TTTS group, 36% (38/106) and 25% (78/308), respectively (p = .04; odds ratio (OR) 1.65; 95% confidence interval (CI): 1.03–2.64). In the subgroup of MC placentas without AA anastomoses, the prevalence of VV anastomoses in the TTTS group and non-TTTS group was 32% (18/57) and 8% (2/25), respectively (p = .03; OR: 5.31; 95% CI: 1.13–24.98). DiscussionVV anastomoses are detected more frequently in TTTS placentas than in MC placentas without TTTS and may thus play a role in the development of TTTS.

Laser surgery in twin–twin transfusion syndrome with proximate cord insertions

ObjectiveTo estimate the prevalence of proximate cord insertions in twin–twin transfusion syndrome (TTTS) and evaluate the outcome after fetoscopic laser coagulation surgery. MethodsWe included all TTTS cases treated with laser at our center between 2002 and 2013. Placentas were examined after birth and injected with colored dye. TTTS cases without complete placental injection study were excluded. We recorded the presence of proximate cord insertions (distance < 5 cm) after birth and the presence and types of residual anastomoses. We compared the clinical outcome and placental findings in cases with and without proximate cord insertions. ResultsThe prevalence of proximate cord insertions in TTTS placentas was 2% (4/252). Perinatal mortality in the TTTS group with and without proximate cord insertions was 13% (1/8) and 12% (61/496), respectively (P = 1.0). Residual anastomoses were detected in all placentas with proximate cord insertions (100%, 4/4) compared to 27% (66/248)(P < .01) in TTTS placentas without proximate cord insertions. ConclusionFetoscopic laser coagulation in TTTS cases with proximate cord insertions is challenging due to technical difficulties in visualizing the vascular equator and results in an increased risk of incomplete laser treatment.

Velamentous cord insertion in monochorionic twins with or without twin–twin transfusion syndrome: Does it matter?

ObjectiveTo study the association between velamentous cord insertion (VCI) and different outcomes in monochorionic twins with and without twin–twin transfusion syndrome (TTTS). MethodsWe recorded the cord insertion type in all consecutive monochorionic placentas examined in two tertiary medical centers. The association between VCI and several outcomes was estimated. ResultsA total of 630 monochorionic placentas with TTTS (n = 304) and without TTTS (n = 326) were studied. The incidence of VCI in the TTTS and non-TTTS group was 36.8% and 35.9%, respectively (P = 0.886). The presence of VCI in one twin was significantly associated with small for gestational age (SGA) status (odds ratio [OR] 1.45, 95% CI 1.13, 1.87) and severe birth weight discordance (OR 3.09, 95% CI 1.93, 4.96). Our results also showed significant interaction between TTTS and VCI when we considered intrauterine fetal demise (IUFD) and gestational age (GA) at birth. The prevalence of IUFD in monochorionic pregnancies without TTTS increased from 4.6% to 14.1% in the presence of VCI (P = 0.027). In the TTTS group, the prevalence of IUFD was comparable in the absence or presence of VCI. Similarly, GA at birth was significantly lower in the presence of VCI only in the non-TTTS group. ConclusionOur findings suggest that VCI is not associated with the development of TTTS but increases the risk of adverse outcomes. Both VCI and TTTS independently increase the prevalence of IUFD and lower GA at birth in a similar way, showing that VCI is an important indicator of adverse perinatal outcome in monochorionic twins.

Maternal Thyroid Function at Gestational Weeks 11–13 in Twin Pregnancies

Thyroid disease during pregnancy may be associated with increased risk of various pregnancy complications. It is known that serum thyrotropin (TSH) is suppressed because of the increased hormone production induced by human chorionic gonadotrophin (hCG) in early pregnancy, and that higher hCG levels in twin pregnancies may cause a more pronounced physiologic suppression. The recognition of this phenomenon is important in order to avoid unnecessary concerns and to correctly establish the diagnosis of overt thyroid disease in twin pregnancies. The aim of this study was to establish reference ranges of maternal serum TSH and free thyroxine (FT4) at gestational weeks 11-13 in twin pregnancies. This is a case series of 177 dichorionic and 58 monochorionic twin pregnancies with normal outcomes, and 19 monochorionic pregnancies complicated by severe twin-twin transfusion syndrome. Maternal serum concentrations of TSH, FT4, antithyroperoxidase, and antithyroglobulin antibodies were measured at gestational weeks 11-13. The measured TSH and FT4 were converted to multiple of median (MoM) of normal singleton pregnancies and MoM values in the different groups were compared. In the antibody-negative twin pregnancies with normal outcomes, compared to singletons, serum TSH MoM was lower (median 0.62 [interquartile range [IQR 0.16-1.18] vs. 1.01 [IQR 0.61-1.51]; p < 0.0001), FT4 MoM was not significantly different (median 0.98 [IQR 0.91-1.08] vs. 0.99 [IQR 0.91-1.09]; p = 0.975), and free β-hCG MoM was higher (median 1.91 [IQR 1.33-2.59] vs. 0.98 [IQR 0.66-1.50]; p < 0.0001). In the antibody-positive group (n = 37), compared to the negative group (n = 198), the median TSH was higher, but FT4 and free β-hCG were not significantly different. In the twin-twin transfusion syndrome group, compared to normal twin pregnancies, TSH, FT4, and free β-hCG were not significantly different. In twins, compared to singleton pregnancies, TSH is lower but FT4 is not significantly different. These reference ranges of thyroid hormones in twins can form the basis for the study of early thyroid function in pathological pregnancies and the investigation of the consequences of overt and subclinical hypothyroidism on twin pregnancy outcome.

Acute peripartum twin–twin transfusion syndrome: Incidence, risk factors, placental characteristics and neonatal outcome

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

Placental magnetic resonance imaging in monochorionic twin pregnancies

Objective: Twin-twin transfusion syndrome (TTTS) is a severe complication of monochorionic pregnancies. Placental hydrops might be a marker for TTTS. The purpose of this study was to evaluate whether differences in the placental parenchyma due to TTTS can be seen with fetal MRI. Methods: In a retrospective study, 34 monochorionic pregnancies were investigated on a 1.5 Tesla MR. Seventeen pregnancies were affected by TTTS, and 17 showed no clinical signs of TTTS. Placental maturation and vascular pathologies, as well as the extent of the placental findings and allocation of placental tissue to each twin, were investigated. Placental findings were reported for origin, size, maturation, and placental thickness, and were correlated with the presence of TTTS. Results: All placentas affected by TTTS showed abnormal maturation on MR scans, but only 64.7% of the non-TTTS group (p = 0.018). Vascular placental pathologies did not differ significantly between the TTTS and non-TTTS group. Conclusions: MR-signs of placental maturity in monochorionic twin pregnancies may indicate a lower risk of development of TTTS.

Relevance of measuring diastolic time intervals in the ductus venosus during the early stages of twin–twin transfusion syndrome

To determine if the discrete myocardial diastolic dysfunction documented previously in the recipient twin during the early stages of twin-twin transfusion syndrome (TTTS) has any repercussion on flow velocities through the ductus venosus (DV) and to investigate if this could allow early differentiation between TTTS and selective intrauterine growth restriction (IUGR). Two groups of monochorionic twin pregnancies with growth discordance between twins were reviewed retrospectively. Group I was composed of fetuses in Stages I and II of TTTS; laser or amnioreduction was not performed in any instance. Group II twin pairs each included one fetus with IUGR due to placental circulatory insufficiency. Intertwin differences (smaller minus larger fetus) were analyzed for myocardial performance index of the right ventricle (MPI-RV) and for time variables in the DV. There were 38 pairs of monochorionic twins (24 TTTS and 14 IUGR) in this study. In the TTTS group, the donors had a significantly lower MPI-RV (0.419 +/- 0.18 vs. 0.596 +/- 0.17, F(1,19df) = 24.017, P < 0.001), a significantly longer total ventricular filling time (150.9 +/- 25.6 ms vs. 124.0 +/- 22.6 ms; F(1,21df) = 19.631, P < 0.001) and a significantly longer early filling time (118.9 +/- 22.9 ms vs. 92.6 +/- 18.9 ms, F(1,21df) = 28.419, P < 0.001) than had the recipient. None of these three differences was present in the IUGR group. Probability studies revealed that cut-off values of 12.75 for intertwin differences in total filling time and 8.5 for intertwin differences in early filling time had sensitivities of 71% and 92%, respectively. The false-positive rates were 23% and 15%, respectively, for the early diagnosis of TTTS. In monochorionic twin pregnancies, shortening of the ventricular filling time in the recipient twin indicates diastolic myocardial dysfunction occurring early in the pathophysiology of TTTS. This early interwin difference in myocardial function is not found in pregnancies with IUGR in one twin due to placental circulatory insufficiency, allowing early differentiation between TTTS and selective IUGR.

Leptin and bone turnover in monochorionic twins complicated by twin–twin transfusion syndrome

To test the hypothesis that the bone metabolism of a growth-restricted foetus is regulated by genetic, placental and/or foetal factors through leptin, we investigated the foetal bone turnover in monochorionic pregnancies complicated with or without twin-twin transfusion syndrome (TTTS). Maternal and cord bloods were collected from gestational-age-matched monochorionic twins with (n=15) and without (n=15) TTTS. The samples were assayed for leptin, cross-linked carboxyl terminal telo-peptide (ICTP, a marker of bone resorption) and pro-peptide (PICP, a marker of bone formation) of type I collagen by radioimmunoassay (RIA). In the growth-restricted donor twin, the plasma concentration of leptin (P < 0.001), PICP (P < 0.001) was lower, while that of ICTP (P < 0.001) was higher than the recipient twin of the TTTS group. In contrast, leptin, PICP and ICTP were comparable in non-TTTS twins. In the recipient twin of TTTS and non-TTTS twins, leptin was positively associated with PICP (r=0.73; n=45, P < 0.001) and negatively with ICTP (r=-0.68; n=45; P < 0.001). No such association was found between leptin and bone marker in the growth-restricted donor twin of the TTTS group. Our data suggest that, in AGA twins, leptin maintains bone metabolism by inhibiting resorption and enhancing bone formation. In contrast, growth-restricted donor twins have high bone turnover and this does not seem to be due to leptin deficiency.

Diagnosis, management and pregnancy outcomes of twin-twin transfusion syndrome

目的 探讨双胎输血综合征的临床诊断、处理及妊娠结局.方法回顾性分析十五年间18例双胎输血综合征(TTTS组)和620例非双胎输血综合征双胎(非TTTS组)的临床资料,比较两组的妊娠并发症、妊娠合并症和妊娠结局. 结果 (1)双胎输血综合征占双胎妊娠总数的2.8%,占单绒毛膜双胎的8.1%;(2)明确分期14例,引产10例,要求保留胎儿7例(Ⅱ期1例、Ⅲ期5例、Ⅳ期1例);3例经腹羊水减量,其中2例转为Ⅴ期后引产,1例胎儿镜下激光凝固胎盘血管交通支,获两活婴;(3)TTTS组辅助生育受孕明显低于非TTTS组(11.1%比40.0%,P＜0.05),胎盘早剥发生率明显高于非TTTS组(22.2%比1.3%,P＜0.05);(4)TTTS组终止妊娠孕周、胎儿平均出生体重显著低于非TTTS组(P＜0.01).TTTS组胎儿死亡、畸形和窒息的发生率分别为41.7%、16.7%和33.3%,显著高于非TTTS组的6.4%、1.9%和7.0%(P＜0.01). 结论 (1)双胎输血综合征严重影响胎儿预后;(2)明确双胎输血综合征的分期有助于临床处理和评估预后;(3)胎儿镜下激光凝固胎盘血管交通支术治疗双胎输血综合征有较好的应用前景。