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Monoamniotic twin pregnancy

INTRODUCTION

Monoamniotic twin pregnancies result from division of a single fertilized oocyte. The fetal membranes consist of one amnion and one chorion (figure 1). These pregnancies are relatively rare and characterized by a high risk of fetal complications, which will be reviewed in the following discussion.

INCIDENCE

The incidence of monoamniotic twins is approximately 1 in 10,000 pregnancies. Monoamnionicity is the least common pattern of twin placentation, affecting only 1 to 5 percent of monozygotic twin gestations [1-3]. (See "Twin pregnancy: Prenatal issues", section on 'Incidence and epidemiology'.)

PATHOGENESIS

Timing of postfertilization division determines placentation in twins:

Diamniotic, dichorionic placentation occurs with division prior to the morula stage (within three days post fertilization).

Diamniotic, monochorionic placentation occurs with division between days 4 and 8 post fertilization.

                    

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Literature review current through: Oct 2014. | This topic last updated: Aug 22, 2014.
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References
Top
  1. Aisenbrey GA, Catanzarite VA, Hurley TJ, et al. Monoamniotic and pseudomonoamniotic twins: sonographic diagnosis, detection of cord entanglement, and obstetric management. Obstet Gynecol 1995; 86:218.
  2. Derom C, Vlietinck R, Derom R, et al. Population-based study on sex proportion in monoamniotic twins. N Engl J Med 1988; 319:119.
  3. Slotnick RN, Ortega JE. Monoamniotic twinning and zona manipulation: a survey of U.S. IVF centers correlating zona manipulation procedures and high-risk twinning frequency. J Assist Reprod Genet 1996; 13:381.
  4. James WH. The sex ratio of monoamniotic twin pairs. Ann Hum Biol 1977; 4:143.
  5. James WH. Sex ratio and placentation in twins. Ann Hum Biol 1980; 7:273.
  6. James WH. A further note on the sex ratio of monoamniotic twins. Ann Hum Biol 1991; 18:471.
  7. Heyborne KD, Porreco RP, Garite TJ, et al. Improved perinatal survival of monoamniotic twins with intensive inpatient monitoring. Am J Obstet Gynecol 2005; 192:96.
  8. Hack KE, Derks JB, Schaap AH, et al. Perinatal outcome of monoamniotic twin pregnancies. Obstet Gynecol 2009; 113:353.
  9. Roqué H, Gillen-Goldstein J, Funai E, et al. Perinatal outcomes in monoamniotic gestations. J Matern Fetal Neonatal Med 2003; 13:414.
  10. Chitnis S, Derom C, Vlietinck R, et al. X chromosome-inactivation patterns confirm the late timing of monoamniotic-MZ twinning. Am J Hum Genet 1999; 65:570.
  11. Meldrum DR, Hamilton M. Response to Slotnich and ortega [Monoamniotic twinning and zone manipulation: a survey of U.S. IVF centers correlating zona manipulation procedures and high-risk twinning frequency (J Assist Reprod Genet 1996; 13:381-385)]. J Assist Reprod Genet 1996; 13:748.
  12. Slotnick RN. Response to Meldrum and Hamilton [monoamniotic twinning and zone manipulation: a survey of U.S. IVF centers correlating zona manipulation procedures and high-risk twinning frequency (J Assist Reprod Genet 1996;13-748)]. J Assist Reprod Genet 1997; 14:365.
  13. Timor-Tritsch IE, Monteagudo A, Horan C, Stangel JJ. Dichorionic triplet pregnancy with the monoamniotic twin pair concordant for omphalocele and bladder exstrophy. Ultrasound Obstet Gynecol 2000; 16:669.
  14. Baldwin V. Twinning mechanisms and zygosity determination. In: Pathology of Multiple Pregnancy, Springer-Verlag, New York 1994. p.17.
  15. Bajoria R. Abundant vascular anastomoses in monoamniotic versus diamniotic monochorionic placentas. Am J Obstet Gynecol 1998; 179:788.
  16. Tannirandorn Y, Phaosavasdi S. Accuracy of ultrasonographic criteria for the prenatal diagnosis of placental amnionicity and chorionicity in twin gestations. J Med Assoc Thai 1993; 76:190.
  17. Blane CE, DiPietro MA, Johnson MZ, et al. Sonographic detection of monoamniotic twins. J Clin Ultrasound 1987; 15:394.
  18. Rodis JF, Vintzileos AM, Campbell WA, et al. Antenatal diagnosis and management of monoamniotic twins. Am J Obstet Gynecol 1987; 157:1255.
  19. Monteagudo A, Timor-Tritsch IE, Sharma S. Early and simple determination of chorionic and amniotic type in multifetal gestations in the first fourteen weeks by high-frequency transvaginal ultrasonography. Am J Obstet Gynecol 1994; 170:824.
  20. Timor-Tritsch IE, Monteagudo A, Peisner DB. High-frequency transvaginal sonographic examination for the potential malformation assessment of the 9-week to 14-week fetus. J Clin Ultrasound 1992; 20:231.
  21. Timor-Tritsch IE. Transvaginal sonographic evaluation of fetal anatomy at 14 to 16 weeks. Why is this technique not attractive in the United States? J Ultrasound Med 2001; 20:705.
  22. Monteagudo A, Timor-Tritsch IE. Ultrasound and multifetal pregnancy. In: Progress in Obstetric and Gynecologic Sonographic Series, Kurjak A (Ed), Parthenon Publishing Group, New York 1998.
  23. Bromley B, Benacerraf B. Using the number of yolk sacs to determine amnionicity in early first trimester monochorionic twins. J Ultrasound Med 1995; 14:415.
  24. Babinszki A, Mukherjee T, Kerenyi T, et al. Diagnosing amnionicity at 6 weeks of pregnancy with transvaginal three-dimensional ultrasonography: case report. Fertil Steril 1999; 71:1161.
  25. Levi CS, Lyons EA, Dashefsky SM, et al. Yolk sac number, size and morphologic features in monochorionic monoamniotic twin pregnancy. Can Assoc Radiol J 1996; 47:98.
  26. Hill LM, Chenevey P, Hecker J, Martin JG. Sonographic determination of first trimester twin chorionicity and amnionicity. J Clin Ultrasound 1996; 24:305.
  27. Bishop DK. Yolk-sac number in monoamniotic twins. Obstet Gynecol 2010; 116 Suppl 2:504.
  28. Murakoshi T, Ishii K, Matsushita M, et al. Monochorionic monoamniotic twin pregnancies with two yolk sacs may not be a rare finding: a report of two cases. Ultrasound Obstet Gynecol 2010; 36:384.
  29. Strohbehn K, Dattel BJ. Pitfalls in the diagnosis of nonconjoined monoamniotic twins. J Perinatol 1995; 15:484.
  30. Arabin B, Laurini RN, van Eyck J. Early prenatal diagnosis of cord entanglement in monoamniotic multiple pregnancies. Ultrasound Obstet Gynecol 1999; 13:181.
  31. Overton TG, Denbow ML, Duncan KR, Fisk NM. First-trimester cord entanglement in monoamniotic twins. Ultrasound Obstet Gynecol 1999; 13:140.
  32. Shahabi S, Donner C, Wallond J, et al. Monoamniotic twin cord entanglement. A case report with color flow Doppler Ultrasonography for antenatal diagnosis. J Reprod Med 1997; 42:740.
  33. Sherer DM, Anyaegbunam A. Prenatal ultrasonographic morphologic assessment of the umbilical cord: a review. Part II. Obstet Gynecol Surv 1997; 52:515.
  34. Nyberg DA, Filly RA, Golbus MS, Stephens JD. Entangled umbilical cords: a sign of monoamniotic twins. J Ultrasound Med 1984; 3:29.
  35. Townsend RR, Filly RA. Sonography of nonconjoined monoamniotic twin pregnancies. J Ultrasound Med 1988; 7:665.
  36. Belfort MA, Moise KJ Jr, Kirshon B, Saade G. The use of color flow Doppler ultrasonography to diagnose umbilical cord entanglement in monoamniotic twin gestations. Am J Obstet Gynecol 1993; 168:601.
  37. Sutter J, Arab H, Manning FA. Monoamniotic twins: antenatal diagnosis and management. Am J Obstet Gynecol 1986; 155:836.
  38. Tabsh K. Genetic amniocentesis in multiple gestation: a new technique to diagnose monoamniotic twins. Obstet Gynecol 1990; 75:296.
  39. Wax JR, Smith JF, Floyd RC. Monoamniotic twins discordant for anencephaly: diagnosis by CT amniography. J Comput Assist Tomogr 1994; 18:152.
  40. Sargent SK, Young W, Crow P, Simpson W. CT amniography: value in detecting a monoamniotic pair in a triplet pregnancy. AJR Am J Roentgenol 1991; 156:559.
  41. Finberg HJ, Clewell WH. Definitive prenatal diagnosis of monoamniotic twins. Swallowed amniotic contrast agent detected in both twins on sonographically selected CT images. J Ultrasound Med 1991; 10:513.
  42. Cook TL, O'Shaughnessy R. Iatrogenic creation of a monoamniotic twin gestation in severe twin-twin transfusion syndrome. J Ultrasound Med 1997; 16:853.
  43. Feldman DM, Odibo A, Campbell WA, Rodis JF. Iatrogenic monoamniotic twins as a complication of therapeutic amniocentesis. Obstet Gynecol 1998; 91:815.
  44. Suzuki S, Ishikawa G, Sawa R, et al. Iatrogenic monoamniotic twin gestation with progressive twin-twin transfusion syndrome. Fetal Diagn Ther 1999; 14:98.
  45. Gilbert WM, Davis SE, Kaplan C, et al. Morbidity associated with prenatal disruption of the dividing membrane in twin gestations. Obstet Gynecol 1991; 78:623.
  46. Sebire NJ, Souka A, Skentou H, et al. First trimester diagnosis of monoamniotic twin pregnancies. Ultrasound Obstet Gynecol 2000; 16:223.
  47. MacLennan A. A template for defining a causal relation between acute intrapartum events and cerebral palsy: international consensus statement. BMJ 1999; 319:1054.
  48. Gaffney G, Squier MV, Johnson A, et al. Clinical associations of prenatal ischaemic white matter injury. Arch Dis Child Fetal Neonatal Ed 1994; 70:F101.
  49. Dias T, Mahsud-Dornan S, Bhide A, et al. Cord entanglement and perinatal outcome in monoamniotic twin pregnancies. Ultrasound Obstet Gynecol 2010; 35:201.
  50. Gembruch U, Baschat AA. True knot of the umbilical cord: transient constrictive effect to umbilical venous blood flow demonstrated by Doppler sonography. Ultrasound Obstet Gynecol 1996; 8:53.
  51. Abuhamad AZ, Mari G, Copel JA, et al. Umbilical artery flow velocity waveforms in monoamniotic twins with cord entanglement. Obstet Gynecol 1995; 86:674.
  52. Rosemond RL, Hinds NE. Persistent abnormal umbilical cord Doppler velocimetry in a monoamniotic twin with cord entanglement. J Ultrasound Med 1998; 17:337.
  53. Rossi AC, Prefumo F. Impact of cord entanglement on perinatal outcome of monoamniotic twins: a systematic review of the literature. Ultrasound Obstet Gynecol 2013; 41:131.
  54. Hack KE, van Gemert MJ, Lopriore E, et al. Placental characteristics of monoamniotic twin pregnancies in relation to perinatal outcome. Placenta 2009; 30:62.
  55. Carr SR, Aronson MP, Coustan DR. Survival rates of monoamniotic twins do not decrease after 30 weeks' gestation. Am J Obstet Gynecol 1990; 163:719.
  56. Tessen JA, Zlatnik FJ. Monoamniotic twins: a retrospective controlled study. Obstet Gynecol 1991; 77:832.
  57. Morikawa M, Yamada T, Yamada T, et al. Prospective risk of intrauterine fetal death in monoamniotic twin pregnancies. Twin Res Hum Genet 2012; 15:522.
  58. Campana MA, Roubicek MM. Maternal and neonatal variables in twins: an epidemiological approach. Acta Genet Med Gemellol (Roma) 1996; 45:461.
  59. Chen CJ, Wang CJ, Yu MW, Lee TK. Perinatal mortality and prevalence of major congenital malformations of twins in Taipei city. Acta Genet Med Gemellol (Roma) 1992; 41:197.
  60. Cameron AH, Edwards JH, Derom R, et al. The value of twin surveys in the study of malformations. Eur J Obstet Gynecol Reprod Biol 1983; 14:347.
  61. Allen VM, Windrim R, Barrett J, Ohlsson A. Management of monoamniotic twin pregnancies: a case series and systematic review of the literature. BJOG 2001; 108:931.
  62. Baxi LV, Walsh CA. Monoamniotic twins in contemporary practice: a single-center study of perinatal outcomes. J Matern Fetal Neonatal Med 2010; 23:506.
  63. Lopoo JB, Paek BW, Maichin GA, et al. Cord ultrasonic transection procedure for selective termination of a monochorionic twin. Fetal Diagn Ther 2000; 15:177.
  64. Young BK, Roqué H, Abdelhak Y, et al. Endoscopic ligation of umbilical cord at 19 week's gestation in monoamniotic monochorionic twins discordant for hypoplastic left heart syndrome. Fetal Diagn Ther 2001; 16:61.
  65. Umur A, van Gemert MJ, Nikkels PG. Monoamniotic-versus diamniotic-monochorionic twin placentas: anastomoses and twin-twin transfusion syndrome. Am J Obstet Gynecol 2003; 189:1325.
  66. Van Mieghem T, De Heus R, Lewi L, et al. Prenatal management of monoamniotic twin pregnancies. Obstet Gynecol 2014; 124:498.
  67. DeFalco LM, Sciscione AC, Megerian G, et al. Inpatient versus outpatient management of monoamniotic twins and outcomes. Am J Perinatol 2006; 23:205.
  68. Ezra Y, Shveiky D, Ophir E, et al. Intensive management and early delivery reduce antenatal mortality in monoamniotic twin pregnancies. Acta Obstet Gynecol Scand 2005; 84:432.
  69. Desai N, Lewis D, Sunday S, Rochelson B. Current antenatal management of monoamniotic twins: a survey of maternal-fetal medicine specialists. J Matern Fetal Neonatal Med 2012; 25:1913.
  70. Raju TN, Mercer BM, Burchfield DJ, Joseph GF Jr. Periviable birth: executive summary of a joint workshop by the Eunice Kennedy Shriver National Institute of Child Health and Human Development, Society for Maternal-Fetal Medicine, American Academy of Pediatrics, and American College of Obstetricians and Gynecologists. Am J Obstet Gynecol 2014; 210:406.
  71. Beasley E, Megerian G, Gerson A, Roberts NS. Monoamniotic twins: case series and proposal for antenatal management. Obstet Gynecol 1999; 93:130.
  72. Cruikshank DP. Intrapartum management of twin gestations. Obstet Gynecol 2007; 109:1167.
  73. Spong CY, Mercer BM, D'alton M, et al. Timing of indicated late-preterm and early-term birth. Obstet Gynecol 2011; 118:323.
  74. Kresch MJ, Lin WH, Thrall RS. Surfactant replacement therapy. Thorax 1996; 51:1137.
  75. Doyle LW, Rogerson S, Chuang SL, et al. Why do preterm infants die in the 1990s? Med J Aust 1999; 170:528.
  76. Mackenzie TC, Crombleholme TM, Johnson MP, et al. The natural history of prenatally diagnosed conjoined twins. J Pediatr Surg 2002; 37:303.