Cord Coagulation Research Articles

Specific complications of monochorionic twin pregnancies: twin–twin transfusion syndrome and twin reversed arterial perfusion sequence

Monochorionic twins are subjected to specific complications which originate in either imbalance or abnormality of the single placenta serving two twins. This unequal placental sharing can cause complications including twin-twin transfusion syndrome (TTTS), twin anemia-polycythemia sequence (TAPS), selective intrauterine growth restriction or twin reversed arterial perfusion sequence (TRAP). Monochorionicity also makes the management of these specific complications as well as that of a severe malformation in one twin hazardous since the spontaneous death of one twin exposes the co-twin to a risk of exsanguination into the dead twin and its placenta. The latter is responsible for the death of the co-twin in up to 20% of the cases and in ischemic sequelae in about the same proportions in the survivors. Although the symptoms of all these complications are very different, the keystone of their management comes down to either surgical destruction of the inter-twin anastomoses on the chorionic plate when aiming at dual survival or selective and permanent occlusion of the cord of a severely affected twin aiming at protecting the normal co-twin. This can be best achieved by fetoscopic selective laser coagulation and bipolar forceps cord coagulation respectively.

Selective reduction in complicated monochorionic pregnancies: radiofrequency ablation vs. bipolar cord coagulation

To compare radiofrequency ablation (RFA) and bipolar cord coagulation (BPC) methods for selective fetal reduction in the treatment of complicated monochorionic (MC) multifetal gestations. This was a retrospective review of patients who underwent selective reduction by RFA and BPC. Computer-generated random sampling was performed to match patients who had undergone BPC with patients who had undergone RFA, in a 2 : 1 ratio, controlling for gestational age and indication. The primary outcome was fetal survival. Twenty patients in the RFA group were matched with 40 patients in the BPC group. Fewer additional intra-operative procedures were performed in the RFA group compared with the BPC group: amnioinfusion, 10% vs. 75%, respectively (P < 0.01); and amnioreduction, 5% vs. 40%, respectively (P = 0.004). The overall survival rates were 87.5% in the RFA group and 88% in the BPC group (P = 0.94). Median gestational age at delivery was 36 (range, 26-41) weeks in the RFA group and 39 (range, 19-40) weeks in the BPC group (P = 0.59). Preterm delivery (at < 28, < 32 or < 37 weeks), weeks gained after the procedure and birth weight at delivery were also similar. Although the preterm premature rupture of membranes (PPROM) rate was higher in the BPC group (22.5%) compared with the RFA group (5%), the difference was not statistically significant (P = 0.09). Overall fetal survival rate following selective reduction in complicated MC pregnancies is similar whether reduction is performed by RFA or BPC. Fewer additional intraoperative procedures are required for RFA than for BPC. The possibility that RFA is associated with a lower rate of postoperative PPROM than is BPC will have to be confirmed in larger series.

Monozygotic triplet pregnancies after single blastocyst transfer: two cases and literature review

Following IVF, single blastocyst transfer has been thought to reduce the risks of high-order multiple pregnancies. This is a report of two cases of monozygotic triplet pregnancies after single blastocyst transfer and a review of the current concepts of the pathogenesis of multiple monozygotic pregnancies as well as the options for managing these high-risk pregnancies. Both cases were reduced to a twin pregnancy by selective cord coagulation at 15-16 weeks. Whereas one patient had uneventful pregnancy until labour was induced for growth arrest and cord Doppler abnormalities in one twin, the other developed a severe twin-to-twin transfusion syndrome which required fetoscopic laser surgery at 21 weeks. In both cases, healthy twins were delivered by Caesarean section at 34.5 and 34 weeks, respectively. As the predictors of their occurrence are not fully understood, patients should be informed of the risks of monozygotic pregnancies after single blastocyst transfer.

Twin anemia polycythemia sequence from a prenatal perspective

To describe the prevalence, management and outcome of spontaneous twin anemia polycythemia sequence (TAPS) diagnosed in the prenatal period. Retrospective analysis of 142 consecutive monochorionic twin pregnancies not diagnosed with twin to twin transfusion syndrome. TAPS cases were identified based on the presence of discordant middle cerebral artery peak systolic velocity (MCA-PSV) measurements and signs suggestive of a chronic intertwin transfusion imbalance: either an elevated reticulocyte count in the anemic twin or the presence of few small unidirectional anastomoses during fetoscopy or at postnatal placental examination. Three cases were identified, giving an estimated prevalence of 2%. Prenatal interventions were tailored to the characteristics of each case and consisted of intrauterine transfusion and interruption of the shared circulation by cord coagulation or laser separation. In monochorionic twin pregnancies, TAPS is an uncommon prenatal finding. Nonetheless, its incidence seems high enough to recommend screening for this disease by MCA-PSV measurements.

Fetal reduction by bipolar cord coagulation in managing complicated monochorionic multiple pregnancies: preliminary experience in China

Background Monochorionic multiple pregnancies (MMPs) are associated with higher rates of perinatal morbidity and mortality caused by interfetal vascular anastomoses in the monochorionic placenta, which can lead to fetal health interactions. In some circumstances, selective feticide of the affected fetus is necessary to save the healthy co-twin. We evaluated the effects and safety of our initial experiences using bipolar cord coagulation for the management of complicated MMPs. Methods Using ultrasound-guided bipolar cord coagulation, we performed selective feticide on 14 complicated MMPs (5 with twin-twin transfusion syndrome, 4 with acardia, 3 with discordant structural anomalies, and 2 with severe selective intrauterine growth restriction). One patient with monochorionic triplets received the procedure twice to terminate 2 affected fetuses for different indications. Data regarding the operations, complications and neonatal outcomes were analyzed. Results Cord occlusions were successfully performed in 13/14 (93%) cases. The failure happened in an acardiac fetus and the pregnancy was terminated by induction. The included cases delivered at a mean gestational age of 35.4 weeks with a perinatal survival rate of 11/13 (85%). Three operation-related complications occurred (21%), including membrane rupture of the terminated sac (1 case), preterm labor at 28 weeks gestation (1 case), and chorioamniotic membrane separation (1 case). Amnioinfusion was indicated in 11 procedures to expand the target sacs for entering the trocar and obtaining sufficient working space. However, in all 4 cases of acardia, the acardiac sacs showed extreme oligohydramnios and could not be well expanded by infusion; thus, the trocar had to be inserted from the sac of the preserved co-twin. Conclusions The application of bipolar cord coagulation in complicated MMPs is safe and improves the prognosis. Amnioinfusion is useful in helping to expand the target sac when the working space is limited.

Direct visual control on cord coagulation using a fetoscopy‐guided bipolar forceps. Description of a new technique

We describe a new technique to achieve permanent umbilical cord occlusion. A 3 mm in diameter bipolar diathermy forceps was built to house a 1.2 mm fetoscope, emerging between the blades of the forceps. The device can be inserted percutaneously through a 10 Fr Trocar into the amniotic cavity under local analgesia and ultrasound guidance. A monochorionic (MC) twin pregnancy with a twin reversed arterial perfusion sequence at 18 weeks of gestation underwent cord occlusion of the acardiac twin using this new device in 2004. The instrument allowed cord coagulation under direct visual control. The pregnancy continued until 33 weeks of gestation when a male infant of 1980 g was delivered by cesarean section following preterm labor. This new instrument might allow easier access to the cord and reduce operation time by direct visualization of the target and, therefore, improve the outcome after the procedure.

Conflits d’intérêts entre jumeaux

The risk of fetal loss is multiplied by 4 in monochorionic pregnancies by comparison with dichorionic one. The incidence of selective growth retardation (sIUGR) is between 12.5 to 25%. This variation is explained by the mixture between pure twin-to-twin transfusion syndrome (TTTS) and pregnancies without TTTS but with a pure sIUGR. The ability to diagnose prenatally sIUGR is low; the positive predictive value is only 37% (EL4). The umbilical flow velocity waveforms with absent diastolic flow (Type II) or with diastolic intermittent flow (Type III) is clearly a strong risk factor of mortality of the IUGR and also a risk factor of leucomalacia of the bigger fetus (EL3). The observed incidence of malformations in twins is 4.05% versus 2.38% for singletons (OR=1.7 [IC 95% 1.47-1.97]). Furthermore, the rate of fetal malformations is higher in monochorionic pregnancies by comparison with dichorionic one, 6.33% versus 3.43% (OR=1.8 [IC 95% 1.3-2.5]) (EL3). In the majority of the cases, the malformation is concerning only one fetus. The most frequent malformations are those of the central nervous system by comparison with singletons, those of the urinary tract and the cardiovascular malformations. Monozygotic pregnancies are not necessarily phenotypically and genetically identical. In situation of asymmetrical malformation, it is necessary to propose fetal karyotype of the malformed fetus. In case aneuploidy of the malformed fetus, secondarily it will be necessary to explore the other apparently normal one. Uniparental disomy should be suspected in such situation (EL3). In TRAP sequence, an intensive follow up should be organised with serial measurement of the respective size of the acardiac fetus and the normal one, Doppler exploration should be done to look for early sign of cardiac decompensation (expert viewpoint). In dichorionic pregnancies, when the malformation is threatening the whole pregnancy like anencephaly, a selective feticide allow a prolongation of the pregnancy, but with a risk of fetal loss of 8% and a risk of iatrogenic prematurity of 12%. In such situation, it could be wise to evaluate the evolution or to wait until the third trimester to undergo the procedure (EL3). In monochorionic pregnancies, in the same situation of anencephalic fetus the best option is bipolar cord coagulation. The result seems to be better after 18 weeks of gestation (EL4). There is a 20% risk of premature rupture of membrane. In the up to date analysis of the literature, there is no formal indication of selective feticide expect case of TRAP sequence with cardiac decompensation of the normal fetus. The very special situation of sIUGR is the object of a randomized trial. In all cases the active participation of the patients to the therapeutic option is mandatory (expert viewpoint).

Fetal abdominal scarring caused by the umbilical cord of a cotwin following selective cord coagulation

Fetal abdominal scarring caused by the umbilical cord of a cotwin following selective cord coagulation

Fetal therapy in twin reserve arterial perfusion sequence pregnancies with alcohol ablation or bipolar cord coagulation

We aimed to evaluate perinatal outcome of seven pregnancies with twin reserve arterial perfusion sequence. Study group included seven cases of acardiac twins. Out of seven acardiac twins, two cases were followed without interventions. We performed four alcohol ablation and one bipolar coagulation. For alcohol ablation, a 20-gauge needle guided with color Doppler USG was directed to abdominal insertion site of the single umbilical artery of the acardiac twin, and 1.0-2.0 mL of absolute alcohol was injected. For bipolar coagulation of the umbilical cord, we used 3.5 mm laparoscopic trocar and 3.0 mm bipolar forceps. The procedures were performed under the guidance of transabdominal ultrasonography. Gestational age of the cases at diagnosis and at delivery was 15-32 and 17-38 weeks, respectively. Two cases without intervention were lost at 17 and 32 weeks. The mean time of procedure for bipolar coagulation and alcohol ablation were 30 and 10 min, respectively. One of the four cases of alcohol ablation group was aborted although alcohol ablation was successful. Another one case was aborted after alcohol ablation due to lost of fetal cardiac activity of the pump fetus. In two other cases, umbilical cord ablation with alcohol was successful, and they delivered live birth at 36 and 38 weeks. In one case, we performed bipolar cord coagulation successfully, and the case delivered live birth at 39 weeks. The overall survival rate for intrauterine surgery was 60% (N 3/5). In twin reserve arterial perfusion sequence pregnancies with findings of poor prognosis, alcohol ablation or bipolar cord coagulation as fetal therapy under the guidance of ultrasonography can be done successfully, and should be offered as a choice to families upon discussion of intervention or follow-up with own complications.

Fetal therapy in twin reversed arterial perfusion sequence pregnancies with alcohol ablation or bipolar cord coagulation

We aimed to evaluate perinatal outcome of seven pregnancies with twin reserve arterial perfusion sequence. The study group included seven cases of acardiac twins. Out of seven acardiac twins, two cases were in follow-up without any interventions. We performed four alcohol ablation and one bipolar coagulation. For alcohol ablation, a 20-gauge needle guided with color Doppler USG was directed to abdominal insertion site of the single umbilical artery of the acardiac twin, and 1.0-2.0 mL of absolute alcohol was injected. For bipolar coagulation of the umbilical cord, we used 3.5 mm laparoscopic trocar and 3.0 mm bipolar forceps. The procedures were performed under the guidance of transabdominal ultrasonography. Gestational age of the cases at diagnosis and at delivery was 15-32 and 17-38 weeks, respectively. Two cases without intervention were lost at 17 and 32 weeks. The mean time of procedure for bipolar coagulation and alcohol ablation were 30 and 10 min, respectively. One of the four cases of alcohol ablation group was aborted although alcohol ablation was successful. The other one case was aborted after alcohol ablation due to lost of fetal cardiac activity of the pump fetus. In two other cases, umbilical cord ablation with alcohol was successful, and they delivered live fetuses at 36 and 38 weeks. In one case we performed bipolar cord coagulation successfully, and the case delivered a live fetus at 39 weeks. The overall survival rate for intrauterine surgery was 60% (N=3/5). In twin reversed arterial perfusion sequence pregnancies with findings of poor prognosis, alcohol ablation or bipolar cord coagulation as fetal therapy under the guidance of ultrasonography can be done successfully, and should be offered as a choice to families upon discussion of intervention or follow-up with own complications.

Intrafetal radiofrequency ablation for twin reversed arterial perfusion (TRAP): a single-center experience

The objective of the study was to review perinatal outcomes in pregnancies treated with intrafetal radiofrequency ablation (RFA) for twin reversed arterial perfusion (TRAP) sequence. Perinatal outcome data from a quaternary care referral center were abstracted from a chart review of pregnancies with TRAP sequence treated in the midtrimester with umbilical cord RFA of the perfused twin. Twenty-one pregnancies with TRAP sequence were evaluated. Two women had a pump twin demise prior to therapy, 1 with trisomy 21 declined treatment. Four of 20 were treated successfully with RFA but remain undelivered, and 1 was treated with fetoscopic cord coagulation. Twelve of 13 pump twins treated with RFA (94%) survived to 30 days of life. Mean preoperative cardiac combined cardiac output was 588 mL/kg and pump/twin ratio was 0.7 (range 0.4 to 1.1). The effect of RFA on postoperative cardiac output was variable (6-85%). The average gestational age at birth was 37 weeks (range 26-39 weeks). Primary therapy with RFA is a successful modality for pregnancies complicated by TRAP sequence.

Selective cord coagulation in acardiac twins

The twin reverse arterial perfusion (TRAP) sequence is a serious complication of monochorionic multiple pregnancies in which the affected twin is reversely perfused from the healthy co-twin, resulting in severely abnormal or absent cardiac development, severe malformations, and massive hydrops fetalis. The acardiac twin threatens the survival of the pump twin either by increasing the risk of congestive cardiac failure or by the development of polyhydramnios, preterm premature rupture of membranes, preterm labour and premature delivery. A wide spectrum of surgical interventions has been applied in the management of TRAP; however, because of the rarity of this condition and the heterogeneity of its presentation, no single technique has been shown to be unequivocally optimal. In our experience, fetoscopic laser coagulation of the placental vascular anastomoses or the umbilical cord of the acardiac twin, with the possibility of applying bipolar forceps as an additional minimally invasive surgical technique, offers an effective treatment option in the management of the TRAP sequence; this treatment has a survival rate of 80%, and 67% of pregnancies with surviving pump twins go beyond 36 weeks of gestation without further complications.

RFA vs cord coagulation in complex monochorionic pregnancies

RFA vs cord coagulation in complex monochorionic pregnancies

P05.05: Fetal selective termination

To asses the pregnancy outcome in multiple pregnancies after selective termination of abnormal fetus. Between May 1993 and April 2005, 23 selective termination were performed in multiple discordant pregnancies (20 twin pregnancies and 3 triple pregnancies). The corionicity was previously established in all the pregnancies. Intracardiac injection of KCl was used in multichorionic pregnancies whereas bipolar cord coagulation under ultrasound guidance was performed in monochorionic gestations. Median maternal age was 33 years. Median gestational age at the procedure was 17 weeks. Indications of the procedure were chromosomal abnormalities in 13 cases and structural abnormalities in 10 cases. Preterm premature rupture of membranes was diagnosed in 5 cases (21%). A termination of the all pregnancy was carried out in one of this cases. In another pregnancy, delivery occurred at 22 weeks. Total fetal loss before 24 weeks was 8% (3/21). Overall fetal survival was 92% (20/23). Median gestational age at delivery was 37 weeks (SD = 4.8). Delivery occurred before 28 weeks in 9% of cases and between 28 weeks and 36 weeks in 9% of cases. Delivery took place after 36 week in 82% of cases. Selective termination for discordant abnormalities is an effective procedure and has an acceptable risk of fetal loss and optimal perinatal results.

Dilemmas in the management of twins discordant for anencephaly diagnosed at 11 + 0 to 13 + 6 weeks of gestation

To help develop an evidence-based approach to the best management of twin pregnancies discordant for anencephaly. We retrospectively examined the management and outcome of 18 pregnancies discordant for anencephaly diagnosed at 11 + 0 to 13 + 6 weeks of gestation in our center. We combined these data with those from other publications. In total, there were 44 dichorionic pregnancies that were managed expectantly (n = 35) or by selective feticide (n = 9) and 19 monochorionic pregnancies that were managed expectantly. We also reviewed the literature to ascertain the outcome of monochorionic twin pregnancies undergoing cord occlusion. In the 35 dichorionic pregnancies that were managed expectantly, 20 (57.1%) developed polyhydramnios at 25-31 weeks; 13 were managed expectantly, five had amniodrainage and two had selective feticide. In 34 of the 35 cases the non-anencephalic twin was liveborn at a median gestation of 36 (range, 28-39) weeks and in six (17.6%) of these it was born before 33 weeks. In the dichorionic pregnancies that had selective feticide, there was one miscarriage and eight (88.9%) live births at a median gestation of 37 (range, 30-40) weeks and in one (12.5%) of these it was born before 33 weeks. In the monochorionic pregnancies, four (21.1%) anencephalic fetuses died at 20-32 weeks and in three of these the normal co-twin also died. In the 16 (84.2%) cases resulting in the live birth of the normal twin, delivery occurred at a median gestation of 33 (range, 27-39) weeks and in six (37.5%) of these it was before 33 weeks. Ultrasound-guided bipolar cord coagulation in 92 pregnancies, mostly complicated by twin reversed arterial perfusion sequence or severe twin-to-twin transfusion syndrome, was associated with a survival rate of 77.2% and early preterm delivery rate of 31.0%. Dichorionic twins discordant for anencephaly are best managed with serial ultrasound examinations for early diagnosis of polyhydramnios, which can then be treated either by amniodrainage or selective feticide. In monochorionic twins it is uncertain whether the best management is expectant or by cord occlusion.

Recent findings on laser treatment of twin-to-twin transfusion syndrome

Despite the recent demonstration of the benefit of the primary laser over amnioreduction, overall survival is far from optimal (70-80%), and therefore diagnosis and management of early and late complications following placental surgery became of great importance. Laser therapy has proven to be better than amnioreduction in treating twin-to-twin transfusion syndrome. Miscarriage, preterm premature rupture of the membranes and preterm delivery account for more than 20% of perinatal mortality after treatment. In those who die despite treatment, recurrence of twin-to-twin transfusion syndrome, placental insufficiency or feto-fetal hemorrhage with anemia/polycythemia are complications that have to be managed with different secondary therapeutic options, such as amnioreduction, cord coagulation, intrauterine transfusion or repeat fetoscopy-guided laser. Ex-vivo placental angiography has confirmed that these complications occur when anastomoses are missed. Early predictors of laser efficacy in twin-to-twin transfusion syndrome treatment, such as improvement in the umbilical vein flow imbalance and urine production, are being evaluated, because they are earlier predictors of outcome than amniotic fluid discordance. Optimization of laser treatment of twin-to-twin transfusion syndrome and new insight into the follow-up are likely to become the key to a better prognosis, and they are therefore important issues that have to be addressed in forthcoming studies.

Prevalence and management of late fetal complications following successful selective laser coagulation of chorionic plate anastomoses in twin-to-twin transfusion syndrome

This study was undertaken to report on the prevalence and management of late complications in twin-to-twin transfusion syndrome (TTTS) treated by laser therapy when both twins are alive 1 week after surgery. A total of 151 consecutive TTTS cases were treated by selective fetoscopic laser therapy. Cases in which both twins were alive 1 week after surgery were followed up with ultrasound and Doppler examination, including middle-cerebral artery peak systolic velocity measurement (MCA-PSV). In the 151 cases treated with laser, both twins were still alive 7 days after the procedure in 101 cases. Intrauterine death of 1 and both twins occurred in 7 and 1 cases, respectively. Recurrence of TTTS with the polyhydramnios-oligohydramnios sequence occurred in 14 (14%) cases. In another 13 (13%) cases, amniotic fluid remained normal in both sacs, but MCA-PSV increased above 1.5 MoM in 1 twin and decreased concomitantly below 0.8 MoM in the co-twin. This was related to anemia and polycythemia, respectively, and resulted from unidirectional feto-fetal blood transfusion, mainly from former recipients into former donors. Late complications were managed accordingly by repeat laser, amnioreduction, cord coagulation, intrauterine blood transfusion, or elective delivery. MCA-PSV Doppler measurements are useful in the follow-up of double survivors to detect and manage late complications after selective laser therapy.

Pregnancy and infant outcome of 80 consecutive cord coagulations in complicated monochorionic multiple pregnancies

This study was undertaken to document pregnancy and infant outcome after cord coagulation with laser and/or bipolar as a technique for selective feticide in complicated monochorionic multiple pregnancies. Prospective follow-up study in 2 tertiary fetal medicine centers. Eighty cases were included in the study (73 twins, 7 triplets). The survival rate was 83% (72/87). There were 9 intrauterine fetal deaths (10%), 5 within 24 hours and 4 between 4 and 10 weeks after the procedure. There was 1 termination of pregnancy because of chorioamnionitis. Median gestational age at delivery was 35.4 weeks, with 79% of patients delivering after 32 weeks. Preterm prelabor rupture of the membranes before 25 weeks accounted for all perinatal deaths (n = 5). Of the children older than 1 year of age (n = 67), 62 (92%) have a normal development. Cord coagulation is an effective method for selective feticide in monochorionic multiple pregnancies.

Diagnosis and management of heterokaryotypic monochorionic twins

The diagnosis, management, and outcome of six consecutive heterokaryotypic monochorionic twins were evaluated. All suspected cases, based on discordant ultrasound findings, underwent amniocentesis of both sacs. Two cases also had chorionic villous sampling (CVS). Dual amniocentesis was superior to CVS in diagnosing heterokaryotypic monochorionic twins. In four cases, the X-chromosome was involved and autosomal aneuploidy was noted in the others. In five cases, the anomalous twin was selectively reduced by cord coagulation. All pregnancies ended with a phenotypically normal liveborn and all children are developing normally at 1-7 years of age.

Intensive fetal surveillance in the first 12 hours following laser treatment in TTTS

TREATMENT IN TTTS MASAMI YAMAMOTO, MOHAMMED ESSAOUI, MALEK NASSAR, YVES VILLE, CAS-HPH Universidad del Desarrollo, Santiago, Chile, CHI Poissy St Germain en Laye, Obstetrics and Gynecology, Poissy, France, CHI Poissy-St Germain, Poissy, France OBJECTIVE: To evaluate closely the twins after laser, and to try to find out which were the patterns of abnormal Doppler and abnormal Urine Production (UP) that led to fetal demise. STUDY DESIGN: 11 consecutive TTTS cases were evaluated before and up to 12 hours after laser, every 2. Umbilical artery (UA), Middle cerebral artery (MCA), Ductus Venosus (DV) and UP were evaluated. End diastolic flow, A wave and PSV below 1.5 MOM were considered normal. The parameters were classified as stable abnormal or normal if they did not changed during the evaluation, and worsening or improving if they changed from the preoperative evaluation. UP was considered improving when the recipient (R) decreased to the half and the donor began urination. All conclusions were analyzed together to describe a pattern of abnormal parameter that could explain fetal demise. RESULTS: 5 pairs of twins survived: Doppler were normal in 3 before and after laser, with UP normalization in R and D. Another case had the same evolution but for the Donor (D) which did not present UP within 12 hours. In the fifth case, absent end diastolic flow in the UA of the D remained unchanged for 12 hours. Two pairs of twins had double fetal demise within 3 days following laser. The Doppler parameters were unchanged for 12 hours in one and MCA-PSV increased in the D in the other, with persistently high UP in the recipient, and absent UP in the D. These could be considered as persistence of TTTS. One case showed high MCA-PSV with severe anemia in the D and UP normalization in the R. This was considered as feto-fetal hemorrhage that was managed with cord coagulation of the donor. Finally, 3 cases presented with the demise of the D within 3 days preceded by worsening of UA Doppler in one, of MCA-PSV in one, and of both parameters in one case. CONCLUSION: Fetal demise within 3 days post-laser was preceded by deterioration in UA or MCA Doppler or persistence of abnormal UP in recipients over the first 12 hours. These are likely to be related to either acute fetal anemia, placental insufficiency or persistent TTTS.