Twin chorionicity and pre-eclampsia.

OBJECTIVE: To determine whether the incidence of pre-eclampsia is different in dichorionic compared to monochorionic twin pregnancies. METHODS: The study involved 666 twin pregnancies resulting in two live births after 24 weeks of gestation. Ultrasound examination at 10-14 weeks of gestation demonstrated that 171 (25.7%) were monochorionic and 495 (74.3%) were dichorionic twins. Pregnancy outcome information regarding the development of pre-eclampsia was obtained from the maternity units. The incidence of pre-eclampsia in the dichorionic and monochorionic twin pregnancies was compared. RESULTS: The incidence of pre-eclampsia in monochorionic twin pregnancies (9.4%) was not significantly different from that in dichorionic pregnancies (7.3%) ( P = 0.48). Multiple logistic regression revealed that chorionicity has no effect on the development of pre-eclampsia after adjusting for maternal age, ethnic group, maternal smoking, parity and gestational age at delivery ( P = 0.6; odds ratio for monochorionic compared with dichorionic twin pregnancies, 1.19; 95% confidence interval, 0.61-2.3). CONCLUSION: In twin pregnancies chorionicity does not affect the incidence of pre-eclampsia.     

Spontaneous septostomy in a monochorionic‐diamniotic twin gestation

Monochorionic twin gestations are associated with a greater incidence of neonatal morbidity and mortality when compared with their dichorionic counterparts. In turn, monochorionic‐monoamniotic (MCMA) gestations carry greater risks compared with monochorionic‐diamniotic (MCDA) gestations. While the true incidence of spontaneous septostomy of the dividing membranes (SSDM) in MCDA twins is unknown, SSDM has been demonstrated to be associated with increased morbidity and mortality, due to functional transition from a MCDA gestation to a MCMA gestation. We report a case of SSDM in a mid‐trimester MCDA gestation, review the literature, and describe how to identify and manage this complication.     

Screening for pre-eclampsia and fetal growth restriction in twin pregnancies at 23 weeks of gestation by transvaginal uterine artery Doppler.

OBJECTIVE: To assess the value of transvaginal uterine artery Doppler at 23 weeks of gestation in predicting the development of adverse perinatal outcomes in twin pregnancies. PATIENTS AND METHODS: Women with twin pregnancies attending for routine ultrasound examination at 23 weeks in any one of seven hospitals underwent Doppler assessment of the uterine arteries. The right and left uterine arteries were identified using color flow mapping and velocity waveforms were obtained using pulsed Doppler. The mean pulsatility index (PI) of the two arteries was determined and the presence of uterine artery notching noted. Results were compared between monochorionic and dichorionic twins, and with our previously reported data from singleton pregnancies. Screening characteristics in the prediction of pre-eclampsia, fetal growth restriction (FGR), placental abruption, fetal death and early preterm delivery were calculated. RESULTS: Uterine artery Doppler at 22-24 weeks of gestation was performed in 360 twin pregnancies, including 324 dichorionic and 36 monochorionic diamniotic twins. Complete outcome data were available in 351 (97.5%). The mean uterine artery PI did not change significantly with gestation and there was no significant difference in mean PI between the dichorionic and monochorionic groups. However, the mean PI was significantly lower in twin pregnancies than in singletons. The pregnancy was complicated by pre-eclampsia in 6.0% of cases, FGR below the 5th centile of both twins in 8.8%, abruption in 0.9%, intrauterine fetal death in 1.7% and early preterm delivery at less than 32 completed weeks of gestation in 5.7% of cases. The respective sensitivities of uterine artery mean PI above the 95th centile for these complications were 33.3%, 9.7%, 66.6%, 33.3% and 18.6%. CONCLUSIONS: In twin pregnancies PI in the uterine arteries is lower than that in singleton pregnancies, but there is no significant difference between dichorionic and monochorionic twins. Doppler assessment of the uterine arteries at 23 weeks identifies a large proportion of twin pregnancies destined to develop adverse outcomes related to uteroplacental insufficiency.     

Prevalence of neurological damage in monochorionic twins with selective intrauterine growth restriction and intermittent absent or reversed end-diastolic umbilical artery flow.

OBJECTIVE: To assess the incidence of parenchymal lesions on early and late neonatal brain scans and its association with the presence or absence of intermittent absent or reversed end-diastolic umbilical artery flow velocity (A/REDV) in monochorionic twins complicated by selective intrauterine growth restriction (IUGR), as compared to dichorionic twins and monochorionic twins without selective IUGR. METHODS: This was a prospective cohort study involving 42 monochorionic twins diagnosed with selective IUGR and managed expectantly. The presence or absence of intermittent A/REDV was recorded in all cases. This study group was compared to dichorionic twins (n = 29) and monochorionic twins without selective IUGR (n = 32) delivered at 26-34 weeks during the study period. All infants underwent an early neonatal brain scan (at or before the fourth day of postnatal life) and at least one follow-up scan during the first 28 days of postnatal life. Perinatal outcome and the incidence of neurological damage were compared between the study groups. RESULTS: The incidence of intrauterine fetal death (IUD) and periventricular leukomalacia was significantly increased in monochorionic twins complicated with selective IUGR, as compared with the other study groups. Intermittent A/REDV was observed in 22/42 (52.4%) twin pairs, and was always present in the growth-restricted twin. The incidence of IUD (overall 9/44 (20.5%) vs. 0/40, P < 0.001; smaller twin 6/22 (27.3%) vs. 0/20, P < 0.05) and parenchymal brain damage (overall 7/35 (20.0%) vs. 2/40 (5.0%), P = 0.07; larger twin 7/19 (36.8%) vs. 1/20 (5.0%), P < 0.05) was significantly higher in pregnancies with intermittent A/REDV than in those without intermittent A/REDV. Brain damage usually occurred in the larger twin, irrespective of whether the smaller twin was liveborn or not. CONCLUSIONS: The presence of intermittent A/REDV in monochorionic twins with selective IUGR identifies a subgroup with an elevated risk of intrauterine demise of the smaller twin and neurological damage in the larger twin; this latter finding is not restricted to cases with IUD of the cotwin.     

Naturally conceived twins with monochorionic placentation have the highest risk of fetal loss.

OBJECTIVE: The aim of this study was to estimate the rate of fetal loss in dichorionic (DC) and monochorionic (MC) twin pregnancies stratified according to zygosity and method of conception. METHODS: In a prospective multicenter observational study women with a twin pregnancy had an ultrasound scan before 14 + 6 weeks' gestation in order to determine chorionicity. The fetal loss rate, the perinatal, neonatal and infant mortality rates and the frequency of very preterm labor were estimated for the different types of twin. RESULTS: Among the 495 pregnancies (421 DC and 74 MC) 229 (46%) were conceived naturally and 266 (54%) by assisted reproduction (AR). Outcome data for 945 liveborn babies were obtained. The spontaneous miscarriage rate before 24 weeks' gestation was 10.9% (7/64) among naturally conceived MC compared to 3.0% (5/165) for naturally conceived DC twins (P < 0.05). For twins conceived by AR the corresponding figures were 0% (0/10) and 0.4% (1/256). The odds ratio (OR) for very preterm birth-before 28 weeks' gestation-was 4.2 for MC twins compared to DC twins. The relative risk of fetal loss or death among DC twins was 20% of the risk for MC twins. CONCLUSION: The risk of fetal loss, very preterm delivery and neonatal/infant death is significantly higher among twins with MC compared to DC placentation. Twins conceived by AR have a much lower risk of MC placentation. The risk of losing one or both twins seems higher among naturally conceived twins compared to twins conceived by AR, despite the fact that the maternal age was higher among the mothers of the AR twins.     

Placental volume in twin and triplet pregnancies measured by three-dimensional ultrasound at 11 + 0 to 13 + 6 weeks of gestation.

OBJECTIVE: To compare the placental volume at 11 + 0 to 13 + 6 weeks' gestation between singleton and multiple pregnancies and to examine the possible effect of chorionicity on placental volume. METHODS: The placental volume was measured by three-dimensional (3D) ultrasound using the Virtual Organ Computer-aided AnaLysis (VOCAL) technique in 290 consecutive twin and 37 triplet pregnancies at 11 + 0 to 13 + 6 weeks of gestation. For the comparison of twin, triplet and singleton placental volumes each measurement was expressed as a multiple of the median (MoM) for singletons, previously established from the study of 417 normal fetuses at 11 + 0 to 13 + 6 weeks of gestation. RESULTS: Median twin and triplet placental volumes were 1.66 and 2.28 MoM for singletons, respectively. In twins the placental volumes increased significantly with gestation from a median of 83.6 mL (5th and 95th centiles: 56.0 mL and 124.9 mL) at 11 + 0 weeks to 149.3 mL (5th and 95th centiles: 100.0 mL and 223.1 mL) at 13 + 6 weeks. The median MoM in monochorionic twins was not significantly different from that in dichorionic twins with fused placentas or dichorionic twins with separate placentas. In triplets the placental volumes increased significantly with gestation from a median of 114.9 mL (5th and 95th centiles: 77.6 mL and 170.1 mL) at 11 weeks to 217.9 mL (5th and 95th centiles: 147.2 mL and 322.5 mL) at 13 + 6 weeks. There were no significant differences in total placental volume between monochorionic and dichorionic triplets, monochorionic and trichorionic triplets, or dichorionic and trichorionic triplets. CONCLUSIONS: Placental volume in multiple pregnancies does not depend on chorionicity, and the rate of placental growth between 11 and 13 + 6 weeks is not significantly different between singletons, twins and triplets. Moreover, for a given gestational age the placental volume corresponding to each fetus in twins and triplets is 83% and 76%, respectively, of the placental volume in singletons.     

Early prenatal sonographic diagnosis of twin triploid gestation presenting with fetal hydrops and theca-lutein ovarian cysts

The presence of theca-lutein ovarian cysts in the early second trimester of pregnancy is highly suspicious for a complete hydatidiform molar pregnancy but can be seen in association with a partial mole. Theca-lutein cysts may occur following hormonal stimulation for assisted reproductive techniques or in association with multiple gestations. Rare causes include immune and nonimmune fetal hydrops, maternal hypothyroidism, and triploid gestations. We report a case of a monochorionic twin gestation in which prenatal sonography demonstrated multiple anomalies and hydrops in each twin and bilateral theca-lutein ovarian cysts. Triploidy in both twins and a partial hydatidiform mole were confirmed at pathologic examination.     

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

OBJECTIVE: To help develop an evidence-based approach to the best management of twin pregnancies discordant for anencephaly. METHODS: 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. RESULTS: 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%. CONCLUSION: 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.     

First trimester diagnosis of monoamniotic twin pregnancies.

This study reports the ultrasound findings and pregnancy outcome for a series of monoamniotic twin pregnancies diagnosed at 11-14 weeks' gestation. Of 315 monochorionic twin pregnancies examined, there were 12 (3.8%) monoamniotic, including four sets of conjoined twins (1.3%). The parents opted for termination of pregnancy in all cases of conjoined twins. In four other cases, there was discordancy for major structural fetal abnormality (kyphoscoliosis, anencephaly, body stalk defect, diaphragmatic hernia), and the cotwin was structurally normal. In the four cases in which both twins were structurally normal, ultrasound examination demonstrated normal nuchal translucency thickness in all cases but cord entanglement was demonstrated from the first trimester. Two cases were managed expectantly; one resulted in livebirth of both twins at 31 weeks' gestation and the second in intrauterine death of both fetuses at 21 weeks. Two pregnancies were treated with Sulindac; one resulted in a single intrauterine death at 30 weeks and delivery of a normal cotwin, the other, in intrauterine death of both fetuses at 31 weeks'. Monoamniotic twin pregnancies are associated with a high risk of fetal abnormalities and perinatal death and the mortality rate is higher than previously reported from series with recruitment later in gestation.     

Changes in prognosis of twin births over 20 years

The study is based on two birth cohorts from the years 1966 and 1985-1986. Perinatal mortality of twins has fallen over 20 years from 9.2% to 3.1%. Improvement is particularly remarkable in neonatal mortality (less than 28 days) of preterm (less than 34 gestational weeks) twins, from 47.4% to 8.6%, whereas the incidence of stillbirths has not fallen greatly. The proportion of preterm births has not fallen significantly, 48.4% vs. 38.1%. Many factors, considered favourable to the course and outcome of pregnancy have improved simultaneously: women are taller, less overweight, and more educated; pregnancies are wanted and sick and maternity leave provisions have improved. The follow-up of twin pregnancies and deliveries has been centralized and is more effective. In particular, neonatal care is also better than 20 years ago. The prognosis of twins has improved in parallel with the singletons, but the perinatal mortality is still approximately four time and the incidence of prematurity ten times more than in singletons.     

Changes in Prognosis of Twin Births over 20 Years

The study is based on two birth cohorts from the years 1966 and 1985–1986. Perinatal mortality of twins has fallen over 20 years from 9.2 % to 3.1 %. Improvement is particularly remarkable in neonatal mortality (28 days) of preterm (34 gestational weeks) twins, from 47.4 % to 8.6 %, whereas the incidence of stillbirths has not fallen greatly. The proportion of preterm births has not fallen significantly, 48.4 % vs. 38.1 %. Many factors, considered favourable to the course and outcome of pregnancy have improved simultaneously: women are taller, less overweight, and more educated; pregnancies are wanted and sick and maternity leave provisions have improved. The follow-up of twin pregnancies and deliveries has been centralized and is more effective. In particular, neonatal care is also better than 20 years ago. The prognosis of twins has improved in parallel with the singletons, but the perinatal mortality is still approximately four time and the incidence of prematurity ten times more than in singletons.     

Hypertrophic cardiomyopathy-like changes in monochorionic twin pregnancies with selective intrauterine growth restriction and intermittent absent/reversed end-diastolic flow in the umbilical artery.

OBJECTIVE: To evaluate the prevalence of hypertrophic cardiomyopathy-like (HCL) changes in monochorionic twins with selective intrauterine growth restriction (sIUGR) and intermittent absent/reversed end-diastolic flow (iAREDF), also defined as Type III sIUGR, and the clinical relevance of this condition. METHODS: A total of 80 pregnancies with sIUGR were studied, 40 with, and 40 without iAREDF. HCL changes were defined as an increased thickness of either left or right ventricular wall (mean > 2 SD) estimated with M-mode ultrasonography. Data were plotted on normal reference values constructed from 75 uncomplicated monochorionic twin pregnancies (150 fetuses) at 22-34 weeks' gestation. Perinatal outcomes in pregnancies with and without HCL changes were compared. RESULTS: In the group with iAREDF, 8/40 of the larger twins (20%) had HCL changes (five bilaterally, two in the right, and one in the left ventricle) as compared with 1/40 (2.5%) in fetuses without iAREDF (P = 0.03). No differences were observed in the smaller twin (1/40 in both groups). HCL changes were not associated with a significant increment in perinatal mortality as only one large fetus from the group with iAREDF died in utero. In the remaining 10 cases, no differences in the intertwin weight discordance, placental surface discordance, or rate of neonatal neurological damage were observed. However, all 10 presented mildly abnormal neonatal cardiac findings that resolved over time with no apparent short-term impact on cardiac function. CONCLUSIONS: HCL changes in the larger twin should be regarded as part of the spectrum of findings in Type III monochorionic-sIUGR (presenting iAREDF). This finding does not seem to be associated with an increased rate of short-term neurological or cardiac complications.     

Using the number of yolk sacs to determine amnionicity in early first trimester monochorionic twins.

The purpose of this study was to evaluate the relationship between the number of yolk sacs and amnionicity in monochorionic twin pregnancies scanned early in the first trimester. We retrospectively reviewed images of all monochorionic twins scanned between 6 and 9.5 weeks' gestation and with pathologic or sonographic confirmation of chorionicity-amnionicity. Each film was reviewed for the number of yolk sacs present, as well as for the gestational age at which the amniotic membrane was first visualized. Twenty monochorionic-diamniotic pregnancies and two monochorionic-monoamniotic pregnancies met the criteria for inclusion in the study. In diamniotic pregnancies scanned at less than 8 weeks' gestation, only the yolk sacs were identified; none of the dividing amniotic membranes were detected. Two yolk sacs were identified in all but one case. In this case, although one yolk sac was seen at 6 weeks, follow-up scanning at 8 weeks revealed two yolk sacs. In each of the monochorionic-monoamniotic twin pregnancies, one yolk sac was seen at 9 weeks and a single amnion encircled both embryos. We conclude that the sonographic identification of two yolk scas in monochorionic twins enables us to make the diagnosis of diamniotic twins early in the first trimester, before the amniotic membrane can be imaged. The presence of one yolk sac should prompt a follow-up ultrasonogram to assign amnionicity definitively.     

Frequency of a monochorionic pair in multiple gestations: relationship to mode of conception.

OBJECTIVE: To determine whether the mode of conception affects the frequency of monochorionicity in multiple gestations. METHODS: Our study population consisted of all women with multiple gestations who had a first-trimester sonogram at our institution between May 1998 and April 2000. The frequency of monochorionicity in pregnancies conceived naturally was compared with the frequency in pregnancies achieved via any form of assisted reproductive technology and among the different types of assisted reproductive technology. RESULTS: Our study consisted of 464 multiple gestations comprising 332 twin, 113 triplet, 16 quadruplet, and 3 quintuplet pregnancies. The higher the fetal number, the more likely the pregnancy resulted from assisted reproductive technology (72.6% of twins, 84.1% of triplets, 92.8% of quadruplets, and 100% of quintuplets; P < .05, Fisher exact test). Monochorionic pairs were found more commonly in naturally conceived pregnancies than in those resulting from assisted reproductive technology (28.2% versus 5.4%; P < .000001, chi2 test). The frequency of monochorionic pairs after in vitro fertilization with blastocyst transfer on day 5 (10.5%) was double the frequency from in vitro fertilization with cleavage stage transfer on day 3 (4.9%), but the difference was not statistically significant (P = .24, Fisher exact test). CONCLUSIONS: Monochorionic pairs are relatively common in naturally conceived twins and in higher-order multiple gestations with more than 3 fetuses arising from assisted reproductive technology, but they are uncommon in twins and triplets arising from assisted reproductive technology There is a trend toward a higher frequency of monochorionic pairs after day 5 blastocyst transfer than day 3 transfer, but a larger study population is needed to confirm this finding.     

不同绒毛膜性质双胎与子痫前期的临床研究

目的 探讨双胎妊娠其绒毛膜性质与子痫前期的关系及其临床特征。方法 纳入413例双胎妊娠病例,根据绒毛膜性质分为单绒毛膜双胎组和双绒毛膜双胎组。比较2组子痫前期发生率的差异,同时比较子痫前期病例中2组的临床特征和围产儿结局的差异。结果 413例双胎中发生子痫前期共62例,其中单绒毛膜双胎子痫前期22例、双绒毛膜双胎子痫前期40例。单绒毛膜双胎组子痫前期发生率为26.2%,高于双绒毛膜双胎组的12.2%（P < 0.001）。子痫前期病例中,与双绒毛膜双胎组相比,单绒毛膜双胎组的发病孕周及分娩孕周更早、24 h尿蛋白定量更高（P均< 0.05）,并且单绒毛膜双胎组新生儿出生体质量较低,其新生儿窒息率及死胎率均较高（P均< 0.05）。结论 与双绒毛膜双胎妊娠相比,单绒毛膜双胎妊娠发生子痫前期的风险更高。在子痫前期病例中,单绒毛膜双胎妊娠比双绒毛膜双胎妊娠发生子痫前期的孕周更早且其围产儿临床预后更差。     

Cord entanglement of monochorionic diamniotic twins following spontaneous antepartum septostomy sonographically simulating a true knot of the umbilical cord.

Spontaneous antepartum septostomy occurring in monochorionic diamniotic twins is extremely rare. We present a case in which prenatal sonography at 26 weeks' gestation depicted a monochorionic diamniotic twin gestation with concordant fetal growth and findings suggestive of a true knot of the umbilical cord. At Cesarean delivery at 34 weeks' gestation, spontaneous antepartum septostomy with entanglement of the two separate umbilical cords was noted. This case suggests that the differential diagnosis of findings considered consistent with a true knot of the umbilical cord in monochorionic diamniotic twin gestations, should include spontaneous antepartum septostomy and umbilical cord entanglement.     

Vanishing twins: the frequency of spontaneous fetal reduction of a twin pregnancy.

This study examines the outcome of 126 twin pregnancies diagnosed by ultrasound examination at 6-16 weeks' gestation. Fifty-nine patients conceived by in vitro fertilization (IVF) and embryo transfer and had a routine scan. The 67 non-IVF pregnancies had a scan for other clinical indications including threatened abortion.When live twins were detected prior to 7 weeks'gestation, only 71% of pregnancies resulted in live twin neonates. Each fetus of a multiple pregnancy had a 19% chance of dying in utero or in the neonatal period of diagnosed prior to 7 weeks, and 11% if both were found to be alive between 7 and 10 weeks. The fetal loss rate was similar for IVF and non-IVF pregnancies.     

Diagnosis and treatment of twin-to-twin transfusion syndrome (TTTS)

This paper is a review of the pathophysiology, diagnosis and treatment of twin-to-twin transfusion syndrome (TTTS).The incidence of fetal or neonatal death and preterm delivery in monochorionic twin pregnancies is substantially higher than in dichorionic twin pregnancies due to TTTS. About 10–15% of all monochorionic twin pregnancies are affected by severe TTTS which is characterized by hypervolemia and polyhydramnios in one fetus, and hypovolemia and anhydramnios in the other one. It is caused by anastomoses between the two vascular systems. With expectant management, i.e. close surveillance, the majority of these pregnancies result in fetal death of both fetuses. Effective treatment is provided by intrauterine laser coagulation of the communicating vessels which allows survival of at least one fetus in about 75% of the cases.     

Management of single fetal death in twin-to-twin transfusion syndrome: a role for fetal blood sampling.

OBJECTIVE: Intrauterine death of one twin in monochorionic pregnancies is associated with an increased mortality and morbidity of the cotwin. This is likely to occur as a consequence of acute hemodynamic changes due to feto-fetal hemorrhage at the time of death of the cotwin. We assessed the role of fetal blood sampling and intrauterine transfusion to rescue the survivor. MATERIALS AND METHODS: We managed 12 cases of single intrauterine death at between 17 and 26 weeks' gestation in monochorionic twins complicated by twin-to-twin transfusion syndrome (TTTS). All these cases had been treated either by laser therapy or by serial amniodrainage. When the demise of one twin occurred, ultrasound-guided fetal blood sampling was performed in the surviving twin using a 20-gauge needle within 24 h of death. Intrauterine transfusion was performed at the same time in cases where the survivor was anemic. All survivors were assessed in the neonatal period and at 1 year of age. RESULTS: Six of the 12 surviving fetuses were found to be anemic and underwent intrauterine transfusion. All fetuses survived the procedure. Four of these fetuses had normal neurological development at 1 year of age. Periventricular leukomalacia developed in one case and the patient underwent termination of pregnancy at 34 weeks. In one case delivery occurred at 34 weeks' gestation and the baby developed periventricular leukomalacia at 1 month of age. In all six non-anemic fetuses pediatric examination was normal at birth and at 1 year of age. CONCLUSION: Intrauterine death of one monochorionic twin in TTTS puts the survivor at high risk of intrauterine death or of developing ischemic/hypoxic lesions. Our results suggest that fetal blood sampling is a useful diagnostic tool to identify those fetuses that are not anemic and hence unlikely to be at risk of developing a cerebral lesion.     

Selective feticide in monochorionic twin pregnancies by ultrasound-guided umbilical cord occlusion.

OBJECTIVES: To evaluate the feasibility and the follow-up of three different ultrasound-guided procedures of selective feticide in monochorionic twin pregnancies. METHODS: This was a retrospective observational study of patients who underwent percutaneous umbilical cord occlusion between July 1993 and January 2002 after diagnosis of previable, abnormal, monochorionic twin pregnancy, with imminent cardiac failure of one of the fetuses. Selective feticide was performed under general anesthesia using three different ultrasound-guided techniques: cord ligation using a suture (four cases), cord coagulation using bipolar forceps (five cases) and cord compression by squeezing the cord against the uterine wall (two cases). RESULTS: During the study period, 11 patients underwent selective feticide before 28 weeks' gestation in our department (eight recipient twins with twin-twin transfusion syndrome (TTTS), one of which also had a congenital diaphragmatic hernia, and three acardiac twins). One procedure failed due to maternal hemorrhage following insertion of the trocar (both fetuses died after emergency Cesarean section). One cotwin died a few minutes after the procedure and one survivor died within the neonatal period. The mean gestational age at the time of the procedure was 24 weeks of gestation and the mean gestational age at delivery was 31.1 weeks. Premature rupture of membranes occurred in four cases. Eight babies were alive and well at the time of writing. CONCLUSIONS: Ultrasound guidance can enable selective feticide to be performed via a single port. Although bipolar coagulation seemed to be the easiest technique, the choice of procedure depends on local conditions.