1
|
Lu J, Ting YH, Leung TY. Determining chorionicity and amnionicity in twin pregnancies: Pitfalls. Best Pract Res Clin Obstet Gynaecol 2022; 84:2-16. [PMID: 35490102 DOI: 10.1016/j.bpobgyn.2022.03.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 03/14/2022] [Indexed: 11/02/2022]
Abstract
Although the accuracy of chorioamnionicity determination in multiple pregnancy is nearly 100%, some pitfalls do exist. These pitfalls may arise from some confusing sonographic appearance or because of certain rare variations of twinning going against the general principles. Pitfalls in chorionicity determination include (1) the disappearance of the twin peak sign with the regression of chorion frondosum and thinning of the intertwin membrane with advancing gestation; (2) fake twin peak sign because of other structures creeping into the intertwin membrane-placental junction; (3) intrauterine septum or synechia being mistaken as a thick intertwin membrane; (4) bipartite placenta in monochorionic twin being misinterpreted as two separate placentas of dichorionic twin; (5) erroneous fetal sex determination in sex chromosome mosaicism, monogenic disorders, and malformed genitalia in one fetus; and (6) rare twinning types such as dizygotic monochorionic twin and sesquizygotic twin. Pitfalls in amnionicity determination are (1) the lack of correlation between the number of yolk sacs and amnionicity and (2) failure to visualize the intertwin membrane because of technical issues.
Collapse
Affiliation(s)
- Jing Lu
- Laboratory of Research and Diagnosis of Gynecological Diseases of Xiamen City, Department of Obstetrics and Gynecology, the First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, China
| | - Yuen Ha Ting
- Department of Obstetrics and Gynecology, The Chinese University of Hong Kong, Hong Kong
| | - Tak Yeung Leung
- Department of Obstetrics and Gynecology, The Chinese University of Hong Kong, Hong Kong.
| |
Collapse
|
2
|
Lu J, Cheng YKY, Ting YH, Law KM, Leung TY. Pitfalls in assessing chorioamnionicity: novel observations and literature review. Am J Obstet Gynecol 2018; 219:242-254. [PMID: 29462630 DOI: 10.1016/j.ajog.2018.02.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 02/07/2018] [Accepted: 02/12/2018] [Indexed: 11/26/2022]
Abstract
Accurate diagnosis of chorioamnionicity in multiple pregnancies is the key to appropriate clinical management of multiple gestation. Although prenatal ultrasound assessment of chorioamnionicity is well established and highly accurate if performed in early pregnancy, exceptions and artifacts arise from anatomic variations in multiple pregnancies and unusual sonographic features do exist. We have summarized our own experiences and reports from the literature on these pitfalls as follows: (1) discordant fetal sex in monochorionic pregnancies due to sex chromosome abnormalities, genital malformation in 1 fetus, or dizygotic twins forming a monochorionic placenta; (2) separate placental masses in monochorionic pregnancies due to bipartite placenta; (3) false-negative and false-positive λ sign can arise for various reasons, and in partial monochorionic/dichorionic placentas both T and λ sign may co-exist; (4) intrauterine synechia appearing as a thick and echogenic intrauterine septum may lead to erroneous diagnosis of dichorionic twins; and (5) errors in ascertaining amnionicity by the visualization of thin intertwin amniotic membranes and the number of yolk sacs. The ultrasound techniques to reduce inaccuracy in prenatal determination of chorioamnionicity and the use of single nucleotide polymorphisms based on noninvasive prenatal test to determine zygosity are also reviewed.
Collapse
|
3
|
Smith J, Treadwell MC, Berman DR. Role of ultrasonography in the management of twin gestation. Int J Gynaecol Obstet 2018. [PMID: 29536536 DOI: 10.1002/ijgo.12483] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Twins represent 1%-2% of all pregnancies, yet continue to account for a disproportionate share of neonatal adverse events including neonatal intensive care admission, morbidity, and mortality. Ultrasonography is central to the proper diagnosis of the type of twinning. Ideally, ultrasonography is performed before 14 weeks of gestation to determine chorionicity and amnionicity. Correct identification of the chorionicity in a twin pregnancy facilitates proper counseling and management of the gestation, including ultrasonography follow-up. Herein, the different types of twinning are reviewed, together with the implications for ultrasonography monitoring of each specific type of twin gestation.
Collapse
Affiliation(s)
- Jessica Smith
- Department of Obstetrics and Gynecology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Marjorie C Treadwell
- Department of Obstetrics and Gynecology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Deborah R Berman
- Department of Obstetrics and Gynecology, University of Michigan Medical School, Ann Arbor, MI, USA
| |
Collapse
|
4
|
Imamura T, Maeda H, Kinoshita H, Kin S. Monochorionic diamniotic twins with centrally located and closely spaced umbilical cord insertions in the placenta. Clin Case Rep 2018; 6:342-345. [PMID: 29445474 PMCID: PMC5799641 DOI: 10.1002/ccr3.1332] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 10/08/2017] [Accepted: 11/28/2017] [Indexed: 11/12/2022] Open
Abstract
When to deliver the monochorionic diamniotic (MCDA) twins with specific cord patterns? Although there is no clear evidence supporting an earlier delivery (before 36 weeks of gestation) in MCDA twins, an earlier delivery might prevent intrauterine death or neuromorbidity in MCDA twins with specific cord patterns.
Collapse
Affiliation(s)
- Takashi Imamura
- Department of Pediatrics Takeda General Hospital Aizu Wakamatsu Fukushima 965-8585 Japan
| | - Hajime Maeda
- Department of Pediatrics Takeda General Hospital Aizu Wakamatsu Fukushima 965-8585 Japan
| | - Hidetoshi Kinoshita
- Department of Pediatrics Takeda General Hospital Aizu Wakamatsu Fukushima 965-8585 Japan
| | - Shogo Kin
- Department of Obstetrics and Gynecology Takeda General Hospital Aizu Wakamatsu Fukushima 965-8585 Japan
| |
Collapse
|
5
|
Luo Q, Han X. Clinical characteristics and outcome of twin pregnancies complicated by single intrauterine death. J Perinat Med 2018; 46:75-79. [PMID: 28306541 DOI: 10.1515/jpm-2017-0008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2017] [Accepted: 02/09/2017] [Indexed: 11/15/2022]
Abstract
AIM To investigate the clinical characteristics and outcome of twin pregnancies complicated by single intrauterine death and how to improve the outcomes of surviving twins. Three thousand three hundred and eighty-four women who delivered twin pregnancies at Women's Hospital, Zhejiang University, School of Medicine were included. Clinical and demographic data on gestational age, etiology, morbidity and mortality for mothers and fetuses were collected. RESULTS The median gestational age for detecting a single intrauterine death in twin pregnancy was 29 weeks and the average gestational age of pregnancy termination was 32 weeks. At least one complication occurred in 93 of 134 mothers (69.4%). The leading causes of a single intrauterine death were umbilical cord abnormality (21.6%), congenital anomalies (17.9%), twin-twin transfusion syndrome (TTTS) (8.2%) and velamentous placenta (7.4%). Of the 134 cases, in 115 cases the remaining twin survived. The birth weight of the surviving twin was significantly higher in pregnancies that continued for more than 1 week after single intrauterine death compared to that ended within 1 week after intrauterine death. CONCLUSIONS Extension of gestation for the surviving twin fetus as long as possible in ensuring the health of the surviving twin and mother, will improve the prognosis of surviving twin after a single intrauterine death.
Collapse
Affiliation(s)
- Qiong Luo
- Department of Obstetrics, Women's Hospital, School of Medicine, Zhejiang University, 1st Xueshi Road, Hangzhou, China
| | - Xiujun Han
- Department of Obstetrics, Women's Hospital, School of Medicine, Zhejiang University, 1st Xueshi Road, Hangzhou, China
| |
Collapse
|
6
|
Maruotti G, Saccone G, Morlando M, Martinelli P. First-trimester ultrasound determination of chorionicity in twin gestations using the lambda sign: a systematic review and meta-analysis. Eur J Obstet Gynecol Reprod Biol 2016; 202:66-70. [DOI: 10.1016/j.ejogrb.2016.04.023] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 04/21/2016] [Indexed: 11/16/2022]
|
7
|
Pacella G, Salsi G, Arcangeli T, Youssef A, Farina A, Bacchi-Reggiani ML, Bellussi F, Mazzella G, Azzaroli F, Porcu E, Rizzo N, Ghi T. The impact of assisted reproductive technology and chorionicity in twin pregnancies complicated by obstetric cholestasis. J Matern Fetal Neonatal Med 2015; 29:1481-4. [DOI: 10.3109/14767058.2015.1051954] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
|
8
|
Kuleva M, Fries N, Castaing O, Moeglin D, Salomon LJ. 'Flash study' on chorionicity determination from ultrasound images at 11-14 weeks' gestation in twin pregnancies. ULTRASOUND IN OBSTETRICS & GYNECOLOGY : THE OFFICIAL JOURNAL OF THE INTERNATIONAL SOCIETY OF ULTRASOUND IN OBSTETRICS AND GYNECOLOGY 2013; 41:471-472. [PMID: 23355187 DOI: 10.1002/uog.12413] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Revised: 12/10/2012] [Accepted: 12/18/2012] [Indexed: 06/01/2023]
|
9
|
Menon DK. A Retrospective Study of the Accuracy of Sonographic Chorionicity Determination in Twin Pregnancies. Twin Res Hum Genet 2012. [DOI: 10.1375/twin.8.3.259] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
AbstractThe aim of this study was to determine the accuracy of sonographic chorionicity determination in the largest sample of twin pregnancies to date. We retrospectively analyzed 463 twin pregnancies delivered over a 6-year period to determine in each case what the antenatal sonographic prediction of chorionicity was, and then what the subsequent post partum pathological diagnosis of chorionicity was. Out of 436 twin pregnancies, 428 were correctly diagnosed for chorionicity as confirmed by pathology reports. Sonography as a screening tool for monochorionic twin pregnancies has a sensitivity of 100%, a specificity of 97.9% and a predictive value positive of 88.2%. Transvaginal scanning in the first trimester determined twin chorionicity with a sensitivity and a specificity of 100%. This study has confirmed in the largest sample to date that sono- graphic chorionicity determination is best done in the first trimester using vaginal scans, where it has 100% accuracy.
Collapse
|
10
|
Devlieger RG, Demeyere T, Deprest JA, Schoubroeck DV, Witters I, Timmerman D, Hanssens M. Ultrasound Determination of Chorionicity in Twin Pregnancy: Accuracy and Operator Experience. ACTA ACUST UNITED AC 2012. [DOI: 10.1375/twin.4.4.223] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
AbstractTo evaluate the accuracy of ultrasound in early detection of chorionicity and amnionicity in twin pregnancies and evaluate the role of operator-experience, a prospective follow up of 87 consecutive twin pregnancies was performed. Chorionicity and amnionicity were determined by 17 different observers, divided in 2 groups on the basis of their experience, using a composite of US markers at the first US examination confirming a viable intrauterine twin pregnancy. Accuracy of prediction was determined for both groups by comparison with postnatal pathology. From the 87 pregnancies examined at 10.1 (minimum 5.5 weeks, maximum 26.0) weeks of gestation, pathology was available in 82 cases and a correct prediction of chorionicity was made in all but two cases, both being diagnosed as monochorionic while dichorionic by observers belonging the more experienced group. No monochorionic pregnancy was missed and amnionicity was correctly diagnosed in all cases, including two monoamniotic twins. We conclude that use of a composite of ultrasound markers for early detection of chorionicity and amnionicity is reliable in a clinical setting where physicians with a variable degree of experience perform ultrasound examination.
Collapse
|
11
|
|
12
|
|
13
|
Alhamdan D, Bora S, Condous G. Diagnosing twins in early pregnancy. Best Pract Res Clin Obstet Gynaecol 2009; 23:453-61. [DOI: 10.1016/j.bpobgyn.2009.02.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2009] [Accepted: 02/25/2009] [Indexed: 10/20/2022]
|
14
|
O'Brien BM. MFM/geneticist view on prenatal management of twins. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2009; 151C:155-61. [PMID: 19378337 DOI: 10.1002/ajmg.c.30210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Twin pregnancies are associated with an increase in both fetal and maternal morbidity and mortality. Health care supervision is complex, increasingly requiring care from maternal-fetal medicine specialists. This review discusses optimal twin prenatal management, which includes recognizing increased twin pregnancy risks specific to twin-types; counseling families regarding fetal complications, ranging from prematurity to cerebral palsy; screening for aneuploidy and open neural tube defects; specific twin guidelines for diagnostic testing, including chorionic villus sampling and amniocentesis; and monitoring for maternal complications.
Collapse
Affiliation(s)
- Barbara M O'Brien
- Division of Maternal Fetal Medicine, Brown University, Providence, RI 02905, USA.
| |
Collapse
|
15
|
Lee YM, Cleary-Goldman J, Thaker HM, Simpson LL. Antenatal sonographic prediction of twin chorionicity. Am J Obstet Gynecol 2006; 195:863-7. [PMID: 16949427 DOI: 10.1016/j.ajog.2006.06.039] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2006] [Revised: 06/02/2006] [Accepted: 06/09/2006] [Indexed: 10/24/2022]
Abstract
OBJECTIVE We sought to determine the accuracy of antenatal diagnosis of twin chorionicity at a single tertiary care center and assess the consequences of incorrect diagnoses. STUDY DESIGN Twins with chorionicity diagnosed by ultrasound < or = 24 weeks' gestation were retrospectively reviewed. Chorionicity was assigned by sonographic findings including placental location(s), the lambda and T-signs, and/or fetal gender(s). Postnatal diagnosis was determined by placental histopathologic examination. Medical records of antenatal-postnatal discordant chorionicities were reviewed for adverse sequelae. RESULTS Chorionicity was correctly assigned antenatally in 392/410 (95.6%) twins. The sensitivity, specificity, and positive and negative predictive values of monochorionicity assessed < or = 14 weeks were 89.8%, 99.5%, 97.8%, and 97.5%. Corresponding statistical values for the second trimester were 88.0%, 94.7%, 88.0%, and 94.7%. Two cases of inaccurate antenatal diagnoses affected patient counseling or were associated with adverse clinical outcomes. CONCLUSION Antenatal assessment of chorionicity is accurate; however, incorrect diagnoses do occur and can affect reliable patient counseling and management.
Collapse
Affiliation(s)
- Young Mi Lee
- Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, Columbia University Medical Center, New York, NY 10032, USA.
| | | | | | | |
Collapse
|
16
|
Shen O, Samueloff A, Beller U, Rabinowitz R. Number of yolk sacs does not predict amnionicity in early first-trimester monochorionic multiple gestations. ULTRASOUND IN OBSTETRICS & GYNECOLOGY : THE OFFICIAL JOURNAL OF THE INTERNATIONAL SOCIETY OF ULTRASOUND IN OBSTETRICS AND GYNECOLOGY 2006; 27:53-55. [PMID: 16276551 DOI: 10.1002/uog.2637] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
OBJECTIVE To determine the relationship between amnionicity and number of yolk sacs before 11 weeks of gestation. METHODS Twenty-two cases of monochorionic multiple pregnancy were scanned before 11 weeks of gestation. There were 21 sets of twins and one of triplets. Amnionicity was determined by visualization of a dividing amniotic membrane between the gestational sacs. The number of yolk sacs was recorded and compared with the presence or absence of a dividing membrane for all fetuses. RESULTS In 17/20 (85%) cases of monochorionic diamniotic twins, two yolk sacs were seen. In 3/20 (15%) cases of monochorionic diamniotic twins, a single yolk sac was seen. In the one case of monochorionic diamniotic triplets, two yolk sacs were visualized. In one case of monoamniotic twins, a single yolk sac was observed. CONCLUSIONS In monochorionic pregnancies, the presence of two yolk sacs predicts diamnionicity. However, the use of the number of yolk sacs as a predictor of amnionicity may not be accurate in a small proportion of patients. The diagnosis of monoamnionicity can be made only following a careful search for a dividing amniotic membrane.
Collapse
Affiliation(s)
- O Shen
- Department of Obstetrics and Gynecology, Shaare Zedek Medical Center, Faculty of Health Sciences, Ben-Gurion University of the Negev, Jerusalem, Israel
| | - A Samueloff
- Department of Obstetrics and Gynecology, Shaare Zedek Medical Center, Faculty of Health Sciences, Ben-Gurion University of the Negev, Jerusalem, Israel
| | - U Beller
- Department of Obstetrics and Gynecology, Shaare Zedek Medical Center, Faculty of Health Sciences, Ben-Gurion University of the Negev, Jerusalem, Israel
| | - R Rabinowitz
- Department of Obstetrics and Gynecology, Shaare Zedek Medical Center, Faculty of Health Sciences, Ben-Gurion University of the Negev, Jerusalem, Israel
| |
Collapse
|
17
|
Abstract
The differentiation between mono- and dichorionic placentation in twin pregnancies is of clinical importance because of the significant difference in perinatal morbidity and mortality between the two, and the increased surveillance indicated in monochorionic gestations. Application of ultrasonography has enabled very precise prenatal determination of chorionicity. While this is best performed in the first trimester when accuracy approaches 100%, even in the third trimester, using a composite cascade of available sonographic features, accuracy has been reported to approach 97%. While two clearly separate placentae or discordant fetal gender conform to dichorionicity, in most twin pregnancies other features need to be assessed to determine chorionicity. The presence of the 'lambda' or the 'T' sign in the presence of a single placenta, best determined in the first trimester, is the most reliable indicator of chorionicity, with measurements of the inter-twin membrane thickness and counting of the membrane layers being less reliable. In this article, we review the sonographic features that help in the accurate depiction of chorionicity.
Collapse
Affiliation(s)
- A Shetty
- Department of Obstetrics and Gynaecology, Aberdeen Maternity Hospital, Cornhill Road, Aberdeen, UK
| | | |
Collapse
|
18
|
Abstract
Advances in assisted reproductive technology and increases in the proportion of maternities in older women have both contributed to the steep increase in the incidence of twin pregnancies since the 1980s. Maternal and perinatal complications are higher in twins than in singleton pregnancies. A significant proportion of perinatal mortality and morbidity among twins is due to the high incidence of preterm delivery and the added complication of twin-to-twin transfusion syndrome (TTTS) in monochorionic twins. Monochorionic twins also have a much higher rate of perinatal mortality than dichorionic twins, the greatest risk being before fetal viability (<24 weeks gestation). Early diagnosis of twins and their chorionicity, close fetal surveillance, particularly of monochorionic twins, and prompt therapeutic intervention in TTS are necessary to reduce perinatal mortality. Intrapartum management in the hospital setting with anaesthetic and neonatal facilities, as well as critical assessment of mode of delivery, have led to better outcomes. Ultrasonography is a valuable tool in the management of twin pregnancy. This chapter briefly summarises these topics, with a particular focus on recent literature.
Collapse
Affiliation(s)
- Anita Rao
- St Helier's University Hospital NHS Trust, Surrey, UK
| | | | | |
Collapse
|
19
|
Abstract
Intrauterine fetal demise of 1 twin in a multiple gestation is a complex clinical situation. Chorionicity, gestational age at diagnosis, problems specific to the pregnancy, and the emotional needs of the patient can impact management. Strategies to optimize outcomes may include a multidisciplinary team approach and fetal surveillance. The following article reviews (1) adverse fetal and neonatal outcomes associated with intrauterine fetal demise of 1 twin, (2) the potential maternal impact, and (3) the strategies to possibly prevent poor outcomes. It is important to remember that even the most vigilant care may not avoid adverse sequelae in a portion of at-risk pregnancies.
Collapse
Affiliation(s)
- Jane Cleary-Goldman
- Department of Obstetrics and Gynecology, Division of Maternal Fetal Medicine, New York Presbyterian Medical Center, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.
| | | |
Collapse
|
20
|
Bracero LA, Byrne DW. Ultrasound determination of chorionicity and perinatal outcome in twin pregnancies using dividing membrane thickness. Gynecol Obstet Invest 2003; 55:50-7. [PMID: 12624553 DOI: 10.1159/000068958] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2001] [Indexed: 11/19/2022]
Abstract
OBJECTIVE To assess the value of ultrasound measurement of twin dividing membrane thickness in predicting chorionicity and perinatal outcome. To compare magnified with unmagnified images, and measurements taken with dividing membranes parallel and perpendicular to the ultrasound beam. METHODS This was a prospective, observational cohort study of twin-pregnancy ultrasound examinations during the second and third trimesters with chorionicity confirmed by a pathologist. Ultrasound measurements of the dividing membrane thickness were recorded in 44 twin pregnancies using unmagnified and magnified images. Measurements were taken at various membrane sites either horizontal or vertical to the ultrasound beam, depending on the orientation of the dividing membrane. We compared the mean membrane thickness between monochorionic and dichorionic pregnancies as well as between pregnancies with good and adverse perinatal outcome. RESULTS Membranes were significantly thicker in dichorionic pregnancies when compared with the monochorionic pregnancies (2.35 vs. 1.69 mm, p = 0.021). A cut-off point of >/=2.0 mm provided a sensitivity of 75.7%, a specificity of 85.7%, a positive predictive value of 96.6%, and a negative predictive value of 40.0%, for determining dichorionicity. Two of 7 monochorionic and 24 of 37 dichorionic pregnancies (59.1%) had good perinatal outcome. These pregnancies had significantly thicker membranes (2.44 vs. 1.96 mm, p = 0.022). Even among the dichorionic pregnancies, a membrane thicker than 2.2 mm was associated with a significantly higher proportion with good perinatal outcome (80.0 vs. 47.1%, relative risk 1.7, p = 0.036). Magnified images obtained with the ultrasound beam parallel to the membrane identified adverse outcome more accurately than unmagnified and perpendicular images. A cut-off point of >2.2 mm for membrane thickness was found to be the best predictor of good outcome. CONCLUSIONS Membrane thickness can be used to identify chorionicity and adverse perinatal outcome, particularly if the ultrasound images are magnified and parallel to the ultrasound beam.
Collapse
Affiliation(s)
- Luis A Bracero
- Department of Obstetrics and Gynecology, Westchester Medical Center, Valhalla, N.Y., USA.
| | | |
Collapse
|
21
|
Eckert MA, Leonard CM, Molloy EA, Blumenthal J, Zijdenbos A, Giedd JN. The epigenesis of planum temporale asymmetry in twins. Cereb Cortex 2002; 12:749-55. [PMID: 12050086 PMCID: PMC2739006 DOI: 10.1093/cercor/12.7.749] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Variation in hemispheric asymmetry of the planum temporale (PT) has been related to verbal ability. The degree to which genetic and environmental factors mediate PT asymmetry is not known. This study examined the heritability for planar asymmetry in 12 dizygotic (DZ) and 27 monozygotic (MZ) male twin pairs who were between 6 and 16 years of age. There was weak but positive evidence for heritability of planar asymmetry. Co-twin similarity for planar asymmetry and Sylvian fissure morphology increased when excluding twins discordant for writing hand and when excluding twins exhibiting birth weight differences >20% from the analyses. Birth weight differences were also related to twin differences in total cerebral volume, but not central sulcus asymmetry. These results suggest that exogenous perinatal factors affect the epigenesis of planar asymmetry development.
Collapse
Affiliation(s)
- Mark A Eckert
- Department of Neuroscience, McKnight Brain Institute of the University of Florida, Gainesville, FL 32610, USA.
| | | | | | | | | | | |
Collapse
|
22
|
Abstract
There has been an increase in the use of fetal ultrasound in the first trimester. This article reviews the published literature with emphasis on fetal nuchal translucency (NT). When measured according to well-defined guidelines, increased NT identifies about 80% of chromosomal anomalies for a false-positive rate of about 5%. Increased NT may indicate the presence of structural defects or genetic disorders, and it is relatively frequently seen in monochorionic pregnancies prone to develop twin-twin transfusion syndrome.
Collapse
Affiliation(s)
- R Snijders
- Department of Public Health, Erasmus University Rotterdam, Rotterdam, The Netherlands.
| |
Collapse
|
23
|
Abstract
Fetal abnormality is more common in multiple than in singleton pregnancies. This, together with the requirement to consider the risks with at least two babies to sample correctly each fetus and to undertake accurately-targeted selective termination, amounts to a major challenge for obstetricians involved in prenatal diagnosis. Early determination of chorionicity should be routine, since this influences not only the genetic risks but also the invasive procedure chosen for karyotyping or genotyping. Assessment of nuchal translucency identifies individual fetuses at risk of trisomy. Contrary to expectation, invasive procedures in twins appear to have procedure-related miscarriage rates that are similar to those in singletons. Instead, contamination remains a concern at chorionic villus sampling. Elective late karyotyping of fetuses may have a role in some countries. Whereas management options for discordant fetal abnormality are relatively straightforward in dichorionic pregnancies, monochorionic pregnancies are at risk of co-twin sequelae after any single intrauterine death. Techniques have now been developed to occlude completely the cord vasculature by laser and/or ultrasound guided bipolar diathermy. Given the complexities associated with prenatal diagnosis, all invasive procedures in multiple pregnancies should be performed in tertiary referral centres.
Collapse
Affiliation(s)
- M J Taylor
- Department of Maternal and Fetal Medicine, Imperial College School of Medicine, Division of Paediatrics, Obstetrics & Gynaecology, Queen Charlotte's & Chelsea Hospital, Goldhawk Road, London, W6 0XG, UK
| | | |
Collapse
|
24
|
Abstract
Monochorionic (MC) twins account for about 20-30% of all twins, but contribute disproportionately to mortality, intrauterine growth restriction, and preterm delivery compared with dichorionic (DC) twins. This higher mortality in MC twins is likely due to the effects of placental morphologic characteristics, which include complex vascular communications between the twins associated with twin-twin transfusion syndrome (TTTS), and the tendency for the common placenta to be shared either symmetrically or asymmetrically. In assessment of clinical outcomes for TTTS, artery to vein anastomoses in the absence of artery to artery or vein to vein, especially if present with placental asymmetry, carry the worse prognosis. Chorion status in twins forms the basis for clinical risk assessment and can be determined by 7 menstrual weeks using transvaginal sonography. The variable results reported in the literature for intertwin umbilical artery Doppler findings in MC twins may be explained by differences between sonographic and clinical criteria (including differential hemoglobin concentrations) reported by various investigators. Antenatal fetal Doppler assessment of the umbilical artery and cerebral arteries can help distinguish between TTTS and placental insufficiency in MC twins. Significant restriction of fetal growth occurs in about 25% of multiple gestations, accounting for about 17% of all growth-retarded infants. Redistribution of fetal blood (brain-sparing effect), as determined by Doppler interrogation of fetal cerebral and umbilical arteries, occurs more commonly in MC twins compared to DC twins and in growth-restricted MC twins compared to nongrowth-restricted MC twins. Overall, the prognosis is poorer for the donor twins in TTTS and there is a greater prenatal death rate for the donor (18-35%), and a higher overall survival rate for recipients following fetoscopic laser treatment. Finally, the clinical and sonographic findings suggest that the polyhydramnios/oligohydramnios sequence seen in MC twins likely represents a spectrum strongly linked to placental variables.
Collapse
Affiliation(s)
- E P Gaziano
- Perinatal Center, Abbott Northwestern Hospital, and Department of Obstetrics and Gynecology, Universtiy of Minnesota, Minneapolis 55407, USA
| | | | | |
Collapse
|
25
|
Sherer DM. Is less intensive fetal surveillance of dichorionic twin gestations justified? ULTRASOUND IN OBSTETRICS & GYNECOLOGY : THE OFFICIAL JOURNAL OF THE INTERNATIONAL SOCIETY OF ULTRASOUND IN OBSTETRICS AND GYNECOLOGY 2000; 15:167-173. [PMID: 10846768 DOI: 10.1046/j.1469-0705.2000.00072.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
|
26
|
Abstract
Determination of chorionicity is of paramount importance in risk assessment and management. Best performed in the first trimester, dichorionic placentation can be reliably assumed when the membrane is easily seen, there is a "twin peak" sign, there are clearly separate placentas, and there is discordant fetal gender. In a monochorionic twin pregnancy, there is a single placental mass, the dividing membrane is difficult to visualize until the end of the first trimester, and the membrane inserts onto the placental surface without a peaked appearance. Amniotic fluid volume assessment is important in the management of twin pregnancy. Polyhydramnios-oligohydramnios may be a manifestation of twin-twin transfusion syndrome, although oligohydramnios with normal amniotic fluid volume in the other twin's sac may more likely be a sign of velamentous cord insertion, infection, or chromosomal or structural abnormality. Fetal growth discordance is common in twin pregnancy and is associated with increased perinatal mortality and morbidity. The most sensitive indicator of discordant twin growth is thought to be estimated fetal weight, and an intertwin difference of > or = 20% is considered significant. In the clinical care of a patient with twins, it is reasonably standard to confirm chorionicity with ultrasonography in the first or early second trimester. At about 20 weeks, a level II ultrasound for anatomic survey is indicated. In dichorionic pregnancies, ultrasound examinations are then performed at 26 to 28 weeks and every 3 to 4 weeks thereafter to follow growth and amniotic fluid volume. In monochorionic twins, we generally do an additional ultrasound at about 23 to 24 weeks, because of the risk of twin-twin transfusion syndrome. In the late third trimester, careful attention should also be given to fetal position, to help with delivery planning.
Collapse
Affiliation(s)
- M E Rode
- Department of Obstetrics and Gynecology, University of Pennsylvania School of Medicine, Philadelphia 19104-4283, USA
| | | |
Collapse
|
27
|
Abstract
The objective was to review current literature pertaining to first trimester ultrasonography of multiple gestations. To this goal, all manuscripts published in the English language regarding this topic were selected and reviewed in a MEDLINE search from 1966 through May 1998. Additional sources were identified through cross-referencing. Current widespread application of first trimester ultrasonography and especially transvaginal sonography has introduced a new dimension in both diagnostic and management aspects of multiple gestations. Application of first trimester ultrasonography in multiple gestations enables an earlier and more precise depiction of important anatomical details regarding fetal viability, chorionicity, pregnancy outcome, structural abnormalities, pathophysiology of developmental disorders (such as twin reverse arterial perfusion [TRAP] sequence), early sonographic signs associated with fetal aneuploidy (nuchal translucency and abnormal crown-rump length), and potential fetal growth discordancy. First trimester ultrasonography also assists in guiding operative procedures including: amniocentesis, chorionic villus sampling, and selective fetal reduction. Enhanced information obtained with high-resolution, first trimester transvaginal ultrasonography is rapidly becoming a standard for establishing critical information that will assist clinicians to stratify management of multiple gestations. Given the increasing incidence of multiple gestations because of various assisted reproductive technology modalities, it is important that obstetricians become aware of the potential advantages of first trimester ultrasonography in clinical management of multiple gestations.
Collapse
Affiliation(s)
- D M Sherer
- Department of Obstetrics and Gynecology & Women's Health, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| |
Collapse
|
28
|
Hendrix NW, Chauhan SP. Sonographic examination of twins. From first trimester to delivery of second fetus. Obstet Gynecol Clin North Am 1998; 25:609-21. [PMID: 9710914 DOI: 10.1016/s0889-8545(05)70030-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Sonographic examination is essential in the diagnosis and management of twin gestation. It assists in determining the zygosity, assessing fetal anomalies, and is integral to amniocentesis if it is necessary, determining the growth and ruling out discordance, and in intrapartum management. The management of uncommon complications with twins also requires ultrasonic survey. Considering that the incidence of multiple gestation is increasing, it would be prudent to become familiar with the use and benefit of ultrasound with twins.
Collapse
Affiliation(s)
- N W Hendrix
- Department of Obstetrics and Gynecology, Medical College of Georgia, Augusta, USA
| | | |
Collapse
|
29
|
Sebire NJ, Nicolaides KH. Screening for fetal abnormalities in multiple pregnancies. BAILLIERE'S CLINICAL OBSTETRICS AND GYNAECOLOGY 1998; 12:19-36. [PMID: 9930287 DOI: 10.1016/s0950-3552(98)80037-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Multiple gestations account for 1-2% of all pregnancies but contribute disproportionately to the incidence of both perinatal loss and fetal structural abnormalities. Ultrasound examination provides essential information about screening for, and the management of, such defects, including accurate determination of chorionicity, assessment of risk, invasive testing and selective termination if appropriate.
Collapse
Affiliation(s)
- N J Sebire
- Harris Birthright Research Centre for Fetal Medicine, Kings College Hospital Medical School, London, UK
| | | |
Collapse
|
30
|
Denbow ML, Fisk NM. The consequences of monochorionic placentation. BAILLIERE'S CLINICAL OBSTETRICS AND GYNAECOLOGY 1998; 12:37-51. [PMID: 9930288 DOI: 10.1016/s0950-3552(98)80038-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Monochorionic (MC) placentation occurs in two-thirds of monozygous twins and approximately 0.3% of all spontaneous conceptions. Vascular anastomoses within the placenta allow intertwin transfusion to occur, which is in most cases a normal event. However, imbalance in this flow may lead to the clinical sequelae observed, with acute, chronic or reverse intertwin transfusion. Acute transfusion describes the events following the death of one of an MC twin pair in utero, with an approximately 1 in 4 chance of demise or neurological damage in the co-twin. Chronic intertwin transfusion, otherwise termed feto-fetal transfusion syndrome, arises following the gradual flux of blood from one twin (the donor) to its sibling fetus (the recipient). The ensuing polyhydramnios places the pregnancy at risk of preterm amniorrhexis and/or labour, notwithstanding the specific sequelae seen in these fetuses following chronic in utero insult. Reverse transfusion describes the most bizarre form of intertwin transfusion: acardiac twinning. Retrograde perfusion of one of the twins with deoxygenated blood leads to the formation of a non-viable acardiac parasite and a 'pump twin' struggling to maintain the cardiac output required to perfuse both twins.
Collapse
Affiliation(s)
- M L Denbow
- Centre for Fetal Care, Imperial College School of Medicine, Queen Charlotte's and Chelsea Hospital, London, UK
| | | |
Collapse
|