Browsing by Author "Papageorghiou, A. T."

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Cord entanglement and perinatal outcome in monoamniotic twin pregnancies
(Wiley, 2010) Dias, T.; Mahsud-Dornan, S.; Bhide, A.; Papageorghiou, A. T.; Thilaganathan, B.
OBJECTIVES: To assess the prevalence of cord entanglement and perinatal outcome in a large series of monoamniotic twin pregnancies and to review the recent literature on similar published large series. METHODS: Prospective observational study of all prenatally detected cases of monoamniotic twin pregnancies during an 8-year period in a tertiary fetal medicine unit. A Medline database review for publications since 2000 containing five or more cases of monoamniotic pregnancies that showed data on cord entanglement and perinatal outcome was also undertaken. RESULTS: A total of 32 monoamniotic pregnancies were diagnosed during the study period, including three conjoined twins, seven pregnancies with twin reversed arterial perfusion (TRAP) syndrome, three surgical pregnancy interruptions for discordant fetal abnormality and one miscarriage before 16 weeks' gestation. The remaining 18 monoamniotic pregnancies were included in the study analysis. All monoamniotic pregnancies were complicated with antenatal cord entanglement diagnosed by B-mode and color Doppler ultrasound. There were 34 live births and a double intrauterine death diagnosed at 19 + 2 weeks' gestation. There were two late neonatal deaths, one from congenital complete heart block and the other after surgery for transposition of the great arteries. The overall perinatal loss rate was 11.1% after 16 weeks and 5.9% after 20 weeks' gestation. The cumulative rates of cord entanglement and perinatal mortality in the reviewed literature were 74% and 21%, respectively. CONCLUSIONS: Umbilical cord entanglement is present in all monoamniotic twins when it is systematically evaluated by ultrasound and color Doppler. Perinatal mortality in monoamniotic twins is mainly a consequence of conjoined twins, TRAP, discordant anomaly and spontaneous miscarriage before 20 weeks' gestation. Expectantly managed monoamniotic twins after 20 weeks have a very good prognosis despite the finding of cord entanglement. The practice of elective very preterm delivery or other interventions to prevent cord accidents in monoamniotic twins should be re-evaluated.
First-trimester ultrasound dating of twin pregnancy: are singleton charts reliable?
(Wiley, 2010) Dias, T.; Mahsud-Dornan, S.; Thilaganathan, B.; Papageorghiou, A. T.; Bhide, A.
OBJECTIVE: The aim of this study was to assess the performance of validated singleton crown-rump length (CRL) formulae in dating twin pregnancies at 11-14 weeks of gestation. DESIGN: Retrospective cohort study. SETTING: Fetal medicine unit of a London teaching hospital. SAMPLE: Three hundred and eighty-four pregnancies with known dates of conception. METHODS: Retrospective analysis of 266 singletons and 118 twin pregnancies conceived by in vitro fertilisation (IVF), with a known date of conception. The gestation calculated from the date of conception was compared with the expected gestation from fetal size using a number of different CRL formulae. MAIN OUTCOME MEASURES: Difference in gestational age computed from fetal size (CRL) of the bigger and smaller fetus in twin pregnancies and singleton pregnancies using three formulae. RESULTS: Two of the three studied CRL formulae systematically underestimated the mean gestational age and size of singleton IVF pregnancies (Robinson formula: gestation = 1.4 days, size = 2.7 mm). Twin CRL measurements straddled those of singletons, regardless of the CRL formula used (Robinson formula: larger twin gestation = 2.4 days, size = 4.7 mm; smaller twin gestation = 0.8 days, size = 1.7 mm). These underestimates in gestation and size for IVF singleton and twin pregnancies are well within the known limits of accuracy of first = trimester ultrasound measurements, and are of limited clinical significance. CONCLUSIONS: Currently available CRL charts underestimate both the age and size of IVF singleton pregnancies by a clinically insignificant amount. This difference is similar for twin pregnancies, suggesting that singleton CRL charts can be used to date twin pregnancies accurately.
Prediction of selective fetal growth restriction and twin-to-twin transfusion syndrome in monochorionic twins
(Wiley, 2012) Memmo, A.; Dias, T.; Mahsud-Dornan, S.; Papageorghiou, A. T.; Bhide, A.; Thilaganathan, B.
OBJECTIVE: To study the correlation of discrepancy between crown-rump length (CRL) and nuchal translucency (NT) in monochorionic twins at 11-14 weeks of gestation and subsequent development of twin-to-twin transfusion syndrome (TTTS) and selective fetal growth restriction (sFGR). DESIGN: Retrospective cohort study. SETTING: Tertiary-care Fetal Medicine Unit, London. SAMPLE: Monochorionic twin pregnancies with known outcome. METHODS: Inter-twin discrepancy was calculated as a percentage of the larger CRL and smaller NT and compared among those developing TTTS, those with sFGR and those with normal outcome. Receiver operating characteristic (ROC) curves were constructed to evaluate the performance of inter-twin discrepancy in prediction of sFGR and TTTS. MAIN OUTCOME MEASURES: Development of TTTS and sFGR. RESULTS: A total of 242 monochorionic twin pregnancies were studied (102 TTTS, 36 sFGR and 104 controls). The median CRL discrepancy in the sFGR group (11.9%) was significantly higher (P < 0.001) than in the TTTS group (3.8%) and control group (3.5%). Median inter-twin NT discrepancies were not significantly different (P = 0.869) between sFGR and both TTTS and control groups (15.6%, 16.7% and 14.8%, respectively). Discrepancy in CRL performs well as a screening test for sFGR (area under ROC curve = 0.89), but not for TTTS (area under ROC curve = 0.58). CONCLUSIONS: First-trimester CRL discrepancy in monochorionic twins is a marker for subsequent development of sFGR rather than TTTS. Inter-twin NT discrepancy does not appear to be significantly different in these two groups from those with normal outcome.
Systematic labeling of twin pregnancies on ultrasound
(Wiley, 2011) Dias, T.; Ladd, S.; Mahsud-Dornan, S.; Bhide, A.; Papageorghiou, A. T.; Thilaganathan, B.
OBJECTIVE: Correct labeling of twin fetuses is needed for consistency in assigning and interpreting longitudinal scan and prenatal screening/diagnostic results. The aim of this study was to describe a standard method of twin labeling in the first trimester of pregnancy and to assess the robustness of such a technique in predicting the presenting twin in subsequent scans and at delivery. METHODS: This was a retrospective first-trimester study of all twin pregnancies assessed by ultrasonography at our center between 2000 and 2010. The fetus contained in the gestational sac closer to the maternal cervix was designated as Twin 1 and the relative orientation of the fetuses to each other was then defined as either lateral (left/right) or vertical (top/bottom). In discordant-sex twins, their sex and presenting order on the final scan prior to delivery were documented and compared with the sex and birth order at delivery. RESULTS: A total of 416 twin pregnancies were seen during the study period. At the 11-14-week scan 90.9% of twins were in lateral orientation while the remainder were oriented vertically. None of the vertically oriented twin pairs but 32 (8.5%) of the laterally oriented twin pairs changed their presenting order between the first and the last ultrasound scan prior to delivery. There were 108 discordant-sex twins scanned in the third trimester, of which the birth order changed in 20.3% that were delivered by Cesarean section and in 5.9% of those delivered vaginally. CONCLUSION: The study demonstrates that antenatal labeling of twins according to laterality or vertical orientation is reliable. The technique ensures continuity of biometric assessment from serial scans at each visit, and as such should be adopted as the preferred method of twin labeling. Furthermore, the use of orientation for antenatal labeling of twins rather than assignment of a number based on proximity to the cervix, precludes any misconception regarding which twin will be born first and ensures that parents and pediatricians are aware of the significant likelihood of a peripartum switch