Septostomy with amniodrainage in the treatment of twin-to-twin transfusion syndrome: a 16-case report

Objective To report the treatment results of 16 monochorionic and diamniotic gestations cases, which had complications due to the twin-to-twin transfusion syndrome (TTTS), the neonatal and other possible complications of the septostomy associated to the amniodrainage. Method Based on ultrasonographic findings, 16 pregnant women were diagnosed with the twin-to-twin transfusion syndrome (TTTS). These cases were divided in two groups: one of them included the fetuses without hydrops and the second included the “recipient” fetuses with hydrops. The therapy measures included septostomy with or without amniodrainage. The following parameters were evaluated: gestational age at the time the septostomy was performed, volume of drained amniotic fluid, gestational age at delivery, birth weight, postnatal evolution, and procedure complications. Results The average gestational age for this procedure was of 23.6 weeks (from 14 weeks and 1 day to 33 weeks). The gestational age for the septostomy until the delivery was of 8.18 weeks (from 1.0 to 21.3 weeks). The survival rate in the group without hydrops was of 68.7%, while in the second group it was of 25%. Some of the complications were as follows: two cases of premature membrane rupture and one case of preterm labor. Conclusion Septostomy with amniodrainage, when performed on the initial stages and on earlier gestational ages has good perinatal results.     

Perinatal outcome following amniotic septostomy in chronic TTTS is independent of placental angioarchitecture.

OBJECTIVES: To determine whether the vascular anatomy of monochorial placenta influences the success of amniotic septostomy for the treatment of chronic mid-trimester twin-twin transfusion syndrome, we report placental anastomoses and perinatal data of 13 pregnancies treated by amniotic septostomy in combination with amnioreduction (AR). The placental anastomoses were delineated postnatally by perfusion studies. Perinatal outcome was also evaluated in relation to umbilical artery Doppler waveform of the donor twin. RESULTS: The median gestational age at septostomy was 21 weeks (range 18 to 25.5 weeks). Amniotic septostomy in combination with single AR procedure successfully resolved polyhydramnios in all cases. The median gestational age at delivery and the septostomy to delivery interval were 27 weeks (range 20 to 34 weeks) and 4 weeks (range 0.3 to 13.6 weeks), respectively. Of the 26 fetuses, 10 died in utero and four died within a week of life, with a combined survival rate of 46%. There was no relation between the clinical outcome and angioarchitecture of the placenta. However, pregnancy loss was higher in the donor twin with absent end-diastolic flow umbilical artery Doppler waveform than those with end-diastolic flow (85 vs 17%; p < 0.001). CONCLUSION: This study suggests that although amniotic septostomy is a promising method for the correction of oligohydramnios and/or polyhydramnios, perinatal survival rate does not depend on angioarchitecture of the placenta. Instead, umbilical artery Doppler waveform of the donor twin may be a better marker for survival rate.     

羊膜带综合征一例

本文报道了1例羊膜带综合征(amniotic band syndrome,ABS)病例。该例孕妇于孕22周+4胎儿系统超声提示未见明显异常,孕30周时,B超发现羊水过多,胎儿水肿可能,收住南京医科大学第一附属医院治疗。入院后予控制血糖,行羊水减量术,B超动态监测羊水指数,每日胎心监护。孕32周起,孕妇出现胎动进行性减少,胎心监护渐呈正弦波样改变;孕32周+3时因胎儿窘迫行急诊剖宫产终止妊娠,术中发现脐带的胎盘插入部见片状羊膜自该处延续至胎儿左下肢近踝部皮肤,羊膜分离呈多孔状,新生儿左踝部可见明显带状缩窄环,左足水肿明显,确诊ABS。该羊膜带对胎儿左足影响较为直接,脐带的胎盘插入部附近的片状羊膜对胎儿是否存在影响尚无足够证据。该早产儿于出生24 h后因"新生儿窒息"死亡。     

Endoscopic documentation of unintentional perforation of the dividing membrane during amnioreduction for twin-twin transfusion syndrome

OBJECTIVE: The purpose of this report is to document endoscopically the occurrence of unintentional piercing of the dividing membrane in a monochorionic twin pregnancy with twin-twin transfusion syndrome (TTTS). MATERIALS AND METHODS: The dividing membrane was visualized endoscopically during laser therapy in a patient with TTTS who had previously undergone therapeutic amniocentesis. The donor twin had no visible bladder, but the amniotic fluid volume had normalized after amniocentesis. RESULTS: The suspected membrane perforation was identified endoscopically during laser surgery. Five areas of vascular communications were identified and photocoagulated. CONCLUSIONS: Sonographic evidence of normalization of the amniotic fluid volumes after therapeutic amniocentesis with persistent nonvisualization of the bladder of the donor twin should not be interpreted as a sign of improvement of TTTS, but rather as indirect evidence of unintentional perforation of the dividing membrane. This complication can be confirmed endoscopically.     

Spontaneous rupture of the dividing membrane in a monochorionic pregnancy resulting in a pseudo-monoamniotic pregnancy with cord entanglement

During pregnancy spontaneous rupture of the dividing membrane of monochorionic diamniotic twins is extremely rare and difficult to diagnose prenatally. We report a case of pseudo-monoamniotic twins derived from monochorionic diamniotic twin gestation. A 37-year-old woman pregnant with monochorionic diamniotic twins initially confirmed by the first trimester ultrasonography, was suspected to have a dividing membrane not visualized on ultrasound examinations at 27 gestational weeks. The woman did not undergo any invasive procedure during pregnancy and did not have notable symptoms. We considered the possibility of spontaneous rupture of the dividing membrane and cord entanglement, and managed the rest of her gestational period as a monoamniotic twin gestation. Concordantly grown healthy male babies were born at 35 weeks and 1 day by elective cesarean section. The mother had complex entangled umbilical cords and a small trace of amniotic membrane in the placenta.     

Morbidity associated with prenatal disruption of the dividing membrane in twin gestations

We report eight cases of intrauterine rupture of the dividing membranes in diamniotic twin gestations and the resulting perinatal morbidity and mortality. The poor outcomes associated with these intrauterine amniotic ruptures included fetal and neonatal death secondary to cord entanglement, preterm rupture of the membranes, preterm labor and delivery, and amniotic band syndrome. The overall perinatal mortality rate was 44% (seven of 16), and the mean gestational age at delivery was 29 weeks (range 22-34). Possible etiologies for this intrauterine diamniotic rupture include fetal trauma to the dividing membranes, amniocentesis, infection, and developmental disturbances. A new theory is examined to explain the surviving twin's morbidity associated with intrauterine death of the co-twin. This study suggests that intrauterine rupture of diamniotic twin membranes carries a perinatal mortality consistent with that of true monoamniotic gestations and that, in fact, this entity may be more common than previously thought. Finally, a suspected monoamniotic gestation cannot be ruled out by the historic presence of a dividing membrane on previous ultrasound examination.     

对单绒毛膜双胎中异常胎儿行脐带双极电凝减胎术的研究

目的 探讨脐带双极电凝法对单绒毛膜双胎中异常胎儿进行选择性减胎术的临床应用价值.方法 选择2007年2-3月中山大学附属第一医院妇产科胎儿医学中心收治的3例一胎异常的单绒毛膜双胎孕妇,其中2例为双胎输血综合征,1例双胎之一为无心畸形,在超声和胎儿镜的引导下应用双极电凝法阻断异常胎儿的脐带血流,以减灭异常胎儿.术后超声连续监测存活胎儿的大脑中动脉和脐动脉的血流频谱,并随访其发育以及母-胎手术并发症.分娩时检查胎儿及胎盘.结果 3例孕妇分别在孕21、22和24周时,应用脐带双极电凝法成功阻断异常胎儿的脐带血流.已经分娩的两例中,1例在减胎术后7 d,死胎发生胎膜破裂,孕32周剖宫产娩出一健康男婴;另1例孕38周剖宫产娩出一健康男婴.2个新生儿1分钟和5分钟Apgar评分均为10分.两例孕妇产后经胎盘病理检查确认为单绒毛膜双胎,死胎脐带可见明显的电凝痕迹.例3目前孕35周,随访结果正常.结论 脐带双极电凝减胎术是适用于单绒毛膜双胎的有效减胎手段,有助于改善正常胎儿的妊娠结局.     

Sonographic umbilical cord morphometry and coiling patterns in twin-twin transfusion syndrome

OBJECTIVE: Monochorionic twins with twin-twin transfusion syndrome (TTTS) provide an ideal model in which to evaluate the influence of differing hemodynamic stress on umbilical cord (UC) morphology. The purpose of this study was to investigate the UC morphometry and UC coiling pattern at ultrasound in monochorionic twin pregnancies with TTTS. METHODS: A targeted sonographic evaluation of the UC was performed in 21 consecutive twin pregnancies with untreated TTTS. The cross-sectional area of the UC and of its vessels was measured. The Wharton's jelly area was computed by subtracting the vessels area from the area of the UC. The umbilical coiling index (UCI) was calculated as the reciprocal of the sonographic length of one complete vascular coil. The UCs were classified as uncoiled, normally coiled, hypocoiled, hypercoiled and atypically coiled (UCI not valuable). RESULTS: The UCs of recipient twins were invariably larger than those of donors, and this difference was mainly attributable to both a larger amount of Wharton's jelly and a larger umbilical vein diameter. The proportion of lean UCs was higher in the donor than in the recipient fetuses (18/21 vs 1/21, p < 0.0001), while large UCs were significantly more frequent in the recipient than in the donor twins (13/21 vs 1/21, p = 0.0002). In all twin pairs, a discordant umbilical coiling pattern was observed between the donor and the recipient twin. The prevalence of uncoiled and hypocoiled cords was higher in the donor group, while hypercoiling and atypical coiling were more frequently detected in the recipient group. CONCLUSIONS: A discordant UC morphometry represents an additional phenotypic feature of twins with TTTS. The discordant intertwin coiling pattern in TTTS argues against an exclusively genetic origin of UC twists, and further supports a key role of hemodynamic forces in coiling development.     

Fetal urine and amniotic fluid in monochorionic twins with twin-twin transfusion syndrome: simulations of therapy

OBJECTIVE: Therapy for twin-twin transfusion syndrome includes amnioreduction, septostomy, and laser ablation, but there is no accepted standard of care. Mechanisms for the reported improvement in survival are incompletely understood. We sought to model the mechanisms and predict the response of varying severities of twin-twin transfusion syndrome and placental angioarchitectures to current therapies to determine optimal clinical interventions. STUDY DESIGN: We used our mathematic model of twin-twin transfusion syndrome that predicts fetal and amniotic fluid abnormalities that are related to the placental angioarchitecture. Amnioreduction was modeled as reduction in amniotic fluid volume; septostomy was modeled as the merging of donor and recipient amniotic fluid, and laser ablation was modeled as the cessation of all placental anastomotic blood flows. RESULTS: Amnioreduction reduces amniotic fluid pressure, which improves transplacental fluid flow from mother to fetus and increases both donor and recipient blood volume. However, net arteriovenous transfusion increases, because of increased donor arterial pressure, which negates, in part, the benefit of amnioreduction. Septostomy allows amniotic fluid to be swallowed by the donor, with minimal effects on donor growth and blood volume. Laser ablation eliminates anastomotic exchange of blood and reduces discordant fetal growth. CONCLUSION: Amnioreduction may be effective in milder twin-twin transfusion syndrome pregnancies but ineffective in severe cases. Septostomy is unlikely to offer significant therapeutic efficacy. Laser ablation is equally effective in mild and severe twin-twin transfusion syndrome but has a higher spontaneous abortion rate than amnioreduction. The model indicates improved outcomes with the use of amnioreduction in mild twin-twin transfusion syndrome cases and with laser ablation in severe cases.     

Twin-twin Transfusion Syndrome

Twin-twin transfusion syndrome (TTTS) is a rare but serious complication of monochorionic twin pregnancy and is associated with a high rate of feted morbidity and mortality. The aetiology of this complication is believed to be secondary to abnormal placental vascular anastomoses. These communications result in an oliguric donor twin and a recipient twin with polyuria causing hydramnios. Untreated, this syndrome may be associated with fetal hydrops, cardiac dysfunction, intra-uterine growth restriction (IUGR) and fetal death. Optimal management includes timely perinatology referral, sonography with confirmation of chorionicity, as well as detailed ultrasound evaluation including fetal echocardiography and possible karyotype analysis. Treatments described include amnioreduction, amniotic septostomy, endoscopic laser ablation of communicating placental vessels and selective fetal cord ligation/occlusion.     

Natural history of twin-twin transfusion syndrome

OBJECTIVE: To determine the natural history of pregnancies with twin-twin transfusion syndrome (TTTS). STUDY DESIGN: All cases of TTTS at our institution since 1991 and in a MED-LINE search since 1966 were retrospectively reviewed. The prenatal diagnosis of TTTS required the presence of monochorionic/diamniotic placentation (absence of twin-peak sign, thin membrane, single placenta, same sex) and of polyhydramnios (largest pocket > 8 cm) in one sac and oligohydramnios (largest pocket < 2 cm or stuck twin) in the other. Only cases diagnosed at < or = 28 weeks were included. Upon diagnosis, all patients were counseled as to the availability, risks and benefits of serial amniocentesis, laser therapy, septostomy, umbilical cord ligation, and other medical and surgical interventions. RESULTS: Of 29 pregnancies identified at our institution with the above strict criteria for TTTS, 5 (17%) declined in utero therapy and were managed expectantly. The mean gestational age at presentation was 19.2 weeks (range, 16-28) and at delivery, 33.8 weeks (range, 22-41). Four (40%) of the twins survived past the neonatal period, and of the three with follow-up, all are free of neurologic sequelae despite the death in utero of their cotwin. From the literature, 136 fetuses with TTTS as defined above and managed expectantly were identified; 37 (27%) survived; 75% (9/12) of survivors with follow-up are neurologically normal. The most recent four studies have reported survival of untreated cases of 50% (17/34) when diagnosed at < or = 26 weeks and of 63% (20/32) when diagnosed at < or = 28 weeks. CONCLUSION: The perinatal survival of TTTS pregnancies managed without in utero procedures is approximately 30% overall and 63% in the four most recent series when diagnosed at < or = 28 weeks. The success of in utero therapeutic intervention should be assessed by randomized studies or at least compared to that in similar cases managed without such intervention.     

Hemodynamic changes with phenotype reversal during pregnancy in twin-twin transfusion syndrome

OBJECTIVES: We report an atypical case of twin-twin transfusion syndrome (TTTS) in monochorionic-diamniotic twins with arterio-arterial anastomoses in which the former donor became the recipient during pregnancy. METHODS: Serial sonographic monitoring was performed. RESULTS: There was a phenotype reversal in TTTS concerning growth and amniotic fluid ending at 27 weeks, with the dominance of the former smaller donor. Doppler sonography changed from absent enddiastolic flow of the donor to normal values in both twins. The new recipient showed transient ascites, the now smaller actual donor (former recipient) developed progressive cardiomegaly, hypertrophy of the myocardium and mitral and tricuspid insufficiency at 29 weeks. Doppler sonography in the new donor deteriorated to highly pathologic flow in the venous system, leading to cesarean section. The donor fetus died 12 h after delivery because of myocardial decompensation. The recipient did very well and was discharged 8 weeks later from the neonatology unit. CONCLUSION: This atypical course shows the importance of serial sonographic monitoring in pregnancies with TTTS.     

Repair of Uterine Rupture in Twin Gestation after Laparoscopic Cornual Resection

Spontaneous uterine rupture in the course of pregnancy is a rare event that usually occurs in a scarred uterus. The event occurs mostly during the intrapartum period and is potentially catastrophic for both mother and fetus. We report a case of 2-cm cornual rupture in a pregnant woman at 13 weeks twin gestation with previous history of cornual pregnancy successfully managed via laparoscopy. Sudden onset of abdominal pain and vaginal bleeding was noted first. Physical examination revealed stable vital signs, lower abdominal tenderness, and mild rebounding pain. Pelvic ultrasonography revealed twin pregnancy at 13 weeks with extrauterine saccular structure 6 cm in diameter located on the left fundus and contiguous with an intrauterine oligohydramnics twin. Exploratory laparotomy was promptly performed, and a small rupture about 2 cm in diameter was observed on the upper portion of the left fundus, the site of a previous laparoscopic cornual resection scar. A protruding amniotic sac of about 6 cm diameter and containing some part of the umbilical cord was seen. The uterine rupture site was repaired directly after aspiration of amniotic fluid from the protruding sac. After surgery, the patient received antibiotics, 17-OH-progesterone for potential rupture of membranes and prematurity. Tocolysis with Ritodrine for irregular uterine contractions was given at 22 weeks gestation. Steroids were given at 24 weeks gestation. The pregnancy ended with a successful delivery by cesarean section because of uncontrollable uterine contractions at 30 5/7 weeks gestation. In conclusion, although termination of pregnancy would normally be recommended when uterine rupture occurs, a different approach to management may now be accepted.     

Discordant fetal leptin levels in monochorionic twins with chronic midtrimester twin-twin transfusion syndrome

The objective of this study was to determine the plasma leptin concentrations in monochorionic twin fetuses with and without twin-twin transfusion syndrome (TTTS). Paired maternal and fetal blood samples were obtained at birth from monochorionic twin pregnancies complicated with (n=12) or without TTTS (n=12). Amniotic fluid samples were also collected from twin pairs at amnioreduction and/or fetal blood sampling in utero. Plasma and amniotic fluid leptin concentrations were measured by radio-immunoassay. Fetal leptin levels in the growth-restricted donor were lower than the recipient twin of the TTTS group (Delta mean 3.7; CI 2.6 to 4.7 ng/ml; P< 0.001). Fetal leptin levels were comparable between non-TTTS twin pairs (Delta mean 0.9; CI 0.1 to 1.4 ng/ml; P=0.10) and recipient twins of TTTS (P=NS). Maternal plasma concentrations of leptin were comparable between the two groups and were higher than the fetal levels. There was a positive association between cord leptin levels and birthweight of twin pairs (y=0.002x-0.37; r=0.58; P< 0.01; n=48). A significant positive relation was also found between delta leptin levels and percentage discordance in birthweight in the TTTS group (y=0.25x-2.21; r=0.82; P< 0.001, n=12). In conclusion, leptin levels in the recipient twins were three times higher than their growth restricted donor twins. However further studies are warranted to elucidate the underlying mechanism.     

Umbilical cord cyst in a monochorionic twin pregnancy: an experiment of nature for the treatment of twin-twin transfusion syndrome

A patient with a monochorionic twin pregnancy developed signs of twin-twin transfusion syndrome from 18 weeks of gestational age. At 23 weeks, an umbilical cord cyst and absent diastolic umbilical artery flow were noted in the donor twin. The pregnancy progressed uncomplicated until term and resulted in vaginal delivery of 2 healthy male babies at 38 weeks of gestational age. We hypothesize that the compression on the umbilical arteries of the donor twin by the umbilical cord cyst has resulted in a partial "compensation" of the twin-twin transfusion phenomenon.     

The progression of disease stage in twin-twin transfusion syndrome.

OBJECTIVE: To estimate the frequency of progression or regression of disease stage in pregnancies complicated by twin-twin transfusion syndrome (TTTS) managed with non-placental laser techniques. METHODS: A cohort of TTTS pregnancies within the sole perinatal center for the state of Western Australia was examined. All cases of prenatally identified TTTS from 1992 to 2002 were staged at diagnosis (retrospectively prior to 2000, prospectively since). Amnioreduction and septostomy were the principal therapies used. Features associated with progression, regression or stability were identified. RESULTS: During the study period, 71 cases of TTTS were managed. Amnioreduction was performed in 73.2%, with no difference in the median number of procedures by stage (p = 0.178). In 21.1% of cases, TTTS resolved completely with persistent normalization of amniotic fluid volumes after amnioreduction (median number of procedures: 2). Disease resolution was associated with pregnancy prolongation, greater gestational age at delivery (36 weeks vs. 28.4 weeks, p < 0.001) and increased perinatal survival (100% vs. 42.6%, p < 0.001) compared with stage progression. Logistic regression analysis predicted that the probability of both infants surviving was 80% if the pregnancy remained at Stage I or II throughout, compared with a probability of 50% if it reached Stage III or more at 26 weeks, and only 25% if the disease reached Stage III or more at 16 weeks' gestation. CONCLUSION: Pregnancy outcome for TTTS managed with amnioreduction techniques is correlated with stage at diagnosis and the subsequent disease evolution. However, the progression of stage in TTTS is unpredictable and the likelihood of spontaneous fetal demise was not different between stages.     

Pregnancies complicated by Twin-Twin transfusion syndrome: outcome and long-term neurological follow-up

OBJECTIVE: To relate prenatal data of monochorionic pregnancies complicated by Twin-Twin transfusion syndrome (TTTS) with survival rates and neurological morbidity. STUDY DESIGN: Thirty-two cases of TTTS underwent biweekly ultrasound examinations. Amnioreduction was the standard of care. Mortality and neurological morbidity were evaluated; the children had neurodevelopmental follow-up with a mean follow-up time of 24 months. RESULTS: Ten out of 32 pregnancies terminated before 24 weeks of gestation, six after induction and four after spontaneous abortion. Among the 22 pregnancies followed up after 24 weeks, the overall survival rate at 28 days was 70% (31/44) with 10 intrauterine deaths including three cases of single selective terminations, and with three neonatal deaths. Eighteen out of 31 babies (58%) had a normal neurological development, eight cases had major and five cases minor neurological disabilities. Neonatal survival was not related to gestational age at diagnosis, number of amnioreductions or weeks at delivery. Absence of end diastolic flow in the umbilical artery, either in the donor or the recipient twin, and birth weight <1000 g were both associated with a higher perinatal mortality. Number of amnioreductions (>2) and birth weight <1000 g were both associated with abnormal neurological follow-up. CONCLUSION: In TTTS, absent end diastolic flow in the umbilical artery and birth weight can predict perinatal survival; neurological development is correlated with number of amnioreductions and birth weight.     

Rapid development of hydrops fetalis in the donor twin following death of the recipient twin in twin-twin transfusion syndrome.

Intrauterine death of one fetus in monochorionic twinning is associated with high rates of perinatal morbidity and mortality in the surviving fetus. Subsequent development of hydrops fetalis in the donor twin after fetal demise of the recipient twin has been described in only two case reports and pathophysiology remains unclear. We report on a monochorionic-diamniotic twin pregnancy complicated by severe twin-twin transfusion syndrome. Ultrasound examination at 20 weeks of gestation showed discrepant twins with oligohydramnios in the smaller twins' sac and polyhydramnios in that of the larger twin. Repeated amniocenteses permitted prolongation of the pregnancy. However, the recipient twin developed deteriorating hydrops fetalis and died at 28 weeks of gestation. After this event, subsequent development of hydrops fetalis in the surviving donor twin could be observed, as well as an increase of amniotic fluid. An elective cesarean section was performed at 29 weeks of gestation. Initial hypoxemia could be effectively treated by high frequency oscillatory ventilation, surfactant therapy and inotropic support. The infant was discharged in good condition at the age of 2 months. Although rare, antenatal demise of the recipient twin in a monochorionic pregnancy can be associated with the subsequent development of hydrops fetalis in the surviving donor twin. We speculate that this phenomenon is due to ischemia-reperfusion injury of the previously poorly perfused twin.     

A stillborn fetus with amniotic band syndrome and elevated levels of alpha-fetoprotein plus beta-human chorionic gonadotropin: a case report

Amniotic band syndrome is an uncommon, congenital fetal abnormality with multiple disfiguring and disabling manifestations. A wide spectrum of clinical deformities are encountered and range from simple ring constrictions to major craniofacial and visceral defects. We report a case of constriction amniotic bands involving upper extremities and intrauterine fetal death due to strangulation of umbilical cord. Abnormally elevated levels of alpha-fetoprotein and beta-chorionic gonadotropin were detected at 17 weeks' gestation. They were probably caused by the loss of cutaneous integrity of the fetus (alpha-fetoprotein), and by the placental attempt to counteract the fetal growth restriction and hypoxia, due to the strangulation of umbilical cord by the amniotic bands (beta-chorionic gonadotropin).     

Laser therapy for twin–twin transfusion syndrome in a dizygotic monochorionic twin pregnancy: A case report

ObjectiveA monochorionic dizygotic (MCDZ) twin is rare, especially when complicated with twin–twin transfusion syndrome (TTTS) and treated by laser therapy.Case reportA pregnancy achieved from oocyte donation and intracytoplasmic sperm injection resulted in two embryos transferred. A monochorionic diamniotic twin pregnancy was diagnosed by an early ultrasound; however, at 16 weeks of gestation, instead of the same sex, the ultrasound suspected there was sex discrepancy between the twins. TTTS with severe polyhydramnios occurred at 22 weeks, leading to a laser therapy, which was followed with a smooth post-operation course. Then the Cesarean section was performed at the gestational age of 29 weeks due to severe preeclampsia, giving birth to two live newborns: one female and one male baby both without neurological sequelae at the time of discharge. Blood chromosomes obtained at delivery and 65 days after delivery all revealed an XX and XY chimera from both babies.ConclusionLaser therapy is also effective in MCDZ twin complicated with TTTS. Determination of chorionicity in early pregnancy could timely prompt us to watch out for complications unique to monochorionic twin pregnancy.