A. Fichera

Increased latency of absent end‐diastolic flow in the umbilical artery of monochorionic twin fetuses

To determine if absent end‐diastolic flow (AEDF) in the umbilical artery (UA) has a longer latency in monochorionic (MC) twin fetuses compared to singleton or dichorionic twin (DC) fetuses.

The use of radiofrequency in the treatment of twin reversed arterial perfusion sequence: a case series and review of the literature

OBJECTIVE To evaluate the initial experience at our centre in the treatment of monochorionic twin pregnancies complicated by twin reversed arterial perfusion sequence (TRAP), using radiofrequency ablation (RFA) with expandable needles, and to review the existing literature on the subject. STUDY DESIGN Between July 2007 and October 2010, 11 monochorionic twin pregnancies complicated by TRAP were referred to our centre. Seven patients underwent intrafetal ablation of the acardiac twin with RFA using LeVeen™ expandable needle electrodes. Data on the procedures and the obstetric outcome were reviewed, and subsequently we performed a review of the literature on the use of RFA in TRAP. RESULTS Median gestational age at the intervention was 17(+3) weeks (range 14(+1)-23(+1) weeks). Technical success was obtained in all cases. Preterm premature rupture of membranes (PPROMs) occurred in 4/7 (57%) patients. Intrauterine death of the pump twin occurred in one patient at 21(+5) weeks, and one patient opted for termination of pregnancy because of PPROM at 21(+4) weeks. Five fetuses were delivered alive at a median gestational age of 33(+0) weeks (range 31(+0)-39(+5) weeks). All five infants (71%) were alive and had a normal examination at 6 months of age. The review identified 6 studies, for a total of 78 pregnancies (either monochorionc twins or triplets with a monochorionic component). Including our data, overall neonatal survival was 75/88 (85%). CONCLUSION RFA appears to be a relatively safe and reliable technique in the treatment of TRAP sequence pregnancies. Further research is needed to define the best timing of the procedure.

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

Abstract 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 2) and birth weight 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.

Perinatal outcome and neurological follow up of the cotwins in twin pregnancies complicated by single intrauterine death

OBJECTIVE To review the outcome of twin pregnancies complicated by single fetal intrauterine death (IUD) managed at our Centre and to evaluate the neurological follow up of the surviving cotwins. STUDY DESIGN Twenty-three twin pregnancies (10 dichorionic and 13 monochorionic diamniotic) complicated by IUD in the II or III trimester were seen at our Centre during the study period (2001-2006). All patients were managed conservatively unless non-reassuring signs of fetal well-being were present at ultrasound examination or CTG after 28 weeks, suggesting immediate delivery. Serial scans after the diagnosis of single death were performed and, in addition, eight monochorionic twin pregnancies underwent prenatal MRI in order to identify the presence of cerebral lesions in the survivors. Live born surviving cotwins underwent neurological follow up. RESULTS In the monochorionic group one cotwin died in utero and one in the neonatal period with a perinatal survival rate of 83.4% (10/12) (excluding one case who opted for termination of pregnancy); in the dichorionic group perinatal survival rate was 100%. In all monochorionic cases there were no signs of ischemic brain lesions in the surviving cotwins at the diagnosis of single death and during ultrasonographic follow up. In monochorionic pregnancies prenatal MRI, when performed, was negative for signs of brain damage in the surviving cotwins. Gestational age at delivery was not statistically different between monochorionic and dichorionic pregnancies (36 (range, 28.4-40.2) vs. 34.6 (range, 28.2-41.3) weeks) (p=0.6) and the rate of early preterm delivery before 32 weeks was 23.8% (5/21) and independent from chorionicity (18.2% vs. 30%, p=0.5). Neurodevelopmental follow up was available for 18/20 live born survivors (85%) and was normal in all but one twin; this case was born from a dichorionic pregnancy with a suspicion of congenital infection. CONCLUSIONS Our data confirmed a trend to a higher risk of perinatal mortality of cotwins in monochorionic twin pregnancies compared to dichorionic ones. In our experience prenatal ultrasound and MRI were useful to exclude cerebral lesions in utero and subsequent neurological sequelae in surviving monochorionic cotwins, even if definitive conclusions, especially on MRI, are limited by the small number of cases in our study.

Antenatal Detection of Arterio-Arterial Anastomoses by Doppler Placental Assessment in Monochorionic Twin Pregnancies

Objectives: To evaluate the reproducibility of Doppler antenatal detection of arterio-arterial anastomoses (AAA) in monochorionic (MC) twin pregnancies. Methods: Between October 2002 and February 2004, 21 MC diamniotic twin pregnancies and one dichorionic triamniotic triplet seen at the Twin Clinic at the University of Brescia were recruited. After routine ultrasonographic assessment, AAA were searched using Color or Power and spectral Doppler. The presence of AAA was confirmed postnatally by placental injection studies. Results: Data of 19 patients were available for the analysis. AAA were detected in 12 cases (63%) antenatally and in 16 (84.2%) at injection study. Sensitivity and specificity of Doppler for detecting AAA were 75 and 100%, respectively. Detection rates increased at advanced gestations and with anterior/fundal placentae. The incidence of twin-twin transfusion syndrome was higher in the group with no AAA detected in vivo compared to the group with AAA found with Doppler (28.5 vs. 16.6%), but the difference was not statistically significant (p = 0.5). Conclusion: This study confirmed the feasibility of AAA Doppler detection in vivo in MC pregnancies.

Rapid cervical phIGFBP-1 test in asymptomatic twin pregnancies: role in mid-pregnancy prediction of spontaneous preterm delivery.

This study aimed to assess the accuracy of a second‐trimester rapid cervical phosphorylated insulin‐like growth factor binding protein‐1 (phIGFBP‐1) test to predict spontaneous preterm delivery in asymptomatic twin pregnancies.

Preliminary experience with microwave ablation for selective feticide in monochorionic twin pregnancies.

Microwave ablation (MWA) is an alternative technique to radiofrequency ablation and laser ablation in the treatment of some solid tumors. In contrast to radiofrequency and laser ablation, we are not aware of previous experiences with MWA in fetal procedures, and report here our preliminary experience. Two cases of monochorionic–diamniotic twins, discordant for fetal abnormalities, underwent selective feticide by MWA between November 2011 and March 2012. Both patients were informed about the nature of the treatment and possible alternatives and gave their written informed consent. MWA was performed using a 2.45-MHz generator (AMICA-GEN, HS Hospital Service, Aprilia, Italy) delivering energy through a 16-gauge internally cooled coaxial antenna. All the procedures were performed percutaneously under ultrasound guidance. Conscious sedation (delorazepam, 5 mg intravenously) and local anesthetic (10 mL of 2% lidocaine) were administered. The antenna was centered in the abdomen of the abnormal fetus close to the insertion of the umbilical cord (Figure 1a). A single microwave energy application was delivered at 50 W net power at the applicator end for 3 min. In both cases, MWA was technically easy, and ultrasound evidence of tissue coagulation was seen immediately after the beginning of energy delivery (Figure 1b). In the first case, one of the twins had a complex cardiac abnormality (dextrocardia, tricuspid atresia, ventricular septal defect, pulmonary stenosis) complicated by hydrops; cervical length was 22 mm. MWA was performed at 17 + 3 weeks’ gestation. There was premature rupture of membranes of the terminated twin 4 days later, and the entire pregnancy miscarried after 7 days. In the second case, one of the twins had anencephaly; cervical length was 40 mm. MWA was performed at 16 + 2 weeks. The pregnancy carried on uneventfully, and a healthy female infant was delivered vaginally at 39 weeks’ gestation. MWA has many potential advantages over radiofrequency and laser ablation: there is immediate evidence of tissue coagulation on ultrasound; the technique is less dependent on tissue properties, as microwave Figure 1 Ultrasound images showing microwave ablation in Case 2. (a) Antenna is centered in abdomen of abnormal fetus close to insertion of umbilical cord. (b) Two min after start of energy delivery, evidence of tissue coagulation can be seen.

Development of customized fetal growth charts in twins

BACKGROUND: Twin gestations are at significantly higher risk of fetal growth restriction in comparison with singletons. Using fetal biometric charts customized for obstetrical and parental characteristics may facilitate an accurate assessment of fetal growth. OBJECTIVE: The objective of the study was to construct reference charts for the gestation of fetal biometric parameters stratified by chorionicity and customized for obstetrical and parental characteristics. STUDY DESIGN: Fetal biometric measurements obtained from serial ultrasound examinations in uncomplicated twin pregnancies delivering after 36 weeks of gestation were collected by 19 Italian fetal medicine units under the auspices of the Società Italiana di Ecografia Ostetrica e Ginecologica. The measurements acquired in each fetus at each examination included biparietal diameter, head circumference, abdominal circumference, and femur length. Multilevel linear regression models were used to adjust for the serial ultrasonographic measurements obtained and the clustering of each fetus in twin pregnancy. The impact of maternal and paternal characteristics (height, weight, ethnicity), parity, fetal sex, and mode of conception was also considered. Models for each parameter were stratified by fetal chorionicity and compared with our previously constructed growth curves for singletons. RESULTS: The data set included 1781 twin pregnancies (dichorionic, n = 1289; monochorionic diamniotic, n = 492) with 8923 ultrasonographic examinations with a median of 5 (range, 2–8) observations per pregnancy in dichorionic and 6 in (range, 2–11) monochorionic pregnancies. Growth curves of twin pregnancies differed from those of singletons, and differences were more marked in monochorionic twins and during the third trimester. A significant influence of parental characteristics was found. CONCLUSION: Curves of fetal biometric measurements in twins are influenced by parental characteristics. There is a reduction in the growth rate during the third trimester. The reference limits for gestation constructed in this study may provide a useful tool for a more accurate assessment of fetal growth in twin pregnancies.

Outcome of monochorionic diamniotic twin pregnancies followed at a single center

We aim to evaluate the outcome of a cohort of monochorionic diamniotic twin pregnancies followed from the first trimester onwards at a single center.

Concordant body stalk anomaly in a monoamniotic twin pregnancy at 9 weeks

gestational weeks. She had anunremarkable medical history and reported no consanguinity.Sonographic examination performed with Philips iU-22ultrasound system using a C10-3v multi-frequency curved arraytransvaginal transducer (Philips, Bothell, WA, USA) revealed amonochorionic monoamniotic twin pregnancy: the gestationalsac contained two live embryos with a crown–rump length of29mm, and no dividing membrane could be identified; a singleyolk sac was identified. Both embryos had a large abdominalwall defect, partial evisceration of abdominal contents andheart, and were connected to the placenta by a short umbilicalcord. Lower limbs were not identified in one fetus and grosslyabnormal in the other; the latter also had a cystic structure atthe caudal pole (Figure 1). The lower part of the body of bothembryos was visualized within the extraembryonic coelom,outside of an apparently intact amniotic membrane. Aftergenetic counseling, estimation of the recurrence risk andexplanation of the severe prognosis, the woman requestedtermination of the pregnancy while refusing fetal karyotyping.A detailed pathological examination of the embryos was notpossible as the specimen obtained after surgical terminationwas severely disrupted.Data on first trimester diagnosis of body stalk anomaly arelimited. In a series of 106,727 nuchal translucency scansperformed at 10–14weeks, 14 fetuses with body stalk anomalywere found.