Expert reviewObstetricsThe vascular anastomoses in monochorionic twin pregnancies and their clinical consequences
Section snippets
Injection studies of the monochorionic placenta
Placental injection from complicated monochorionic twin gestations often provides exceptionally useful information that would otherwise be lost on routine pathological examination. Nevertheless, placentas from pregnancies complicated with single death and delayed delivery can no longer be evaluated because of postmortem involution of the placental part of the demised twin.
Although placental injection is time-consuming, it is basically a simple technique that can be performed by anyone with
TTTS
TTTS is an antenatal sonographic diagnosis based on the presence of polyhydramnios (deepest vertical pocket ≥8 cm) with a distended bladder in the recipient and oligohydramnios (deepest vertical pocket ≤2 cm) with a small or empty bladder in the donor. Because amniotic fluid increases with gestation, most Europeans adhere to the gestational age-dependent cutoff of a deepest pocket ≥10 cm after 20 weeks to define the degree of polyhydramnios. “Twin-to-twin transfusion syndrome” is somewhat a
TAPS
In contrast to TTTS, which is essentially an amniotic fluid discordance, TAPS is characterized by a severe hemoglobin discordance caused by a chronic net transfusion over minuscule and usually unidirectional anastomoses. TAPS can be diagnosed antenatally based on discordant MCA-PSV measurements. One twin typically has an elevated MCA-PSV (>1.5 multiples of the median) and in the other twin the MCA-PSV is decreased (<1 multiples of the median).25 The anemic twin often has decreased amniotic
Conclusion
In summary, the vascular anastomoses are responsible for some unique complications in monochorionic twin pregnancies. They also account for the increased mortality and morbidity as compared to dichorionic twins, which have separate circulations. As long as the twins are connected to this shared circulation, intertwin transfusion imbalances may occur and each twin is exposed to the hormonal environment of its cotwin. The shared circulation is also responsible for the fact that the well-being of
References (75)
- et al.
The outcome of monochorionic diamniotic twin gestations in the era of invasive fetal therapy: a prospective cohort study
Am J Obstet Gynecol
(2008) - et al.
Twin chorionicity and the risk of adverse perinatal outcome
Int J Gynaecol Obstet
(2007) - et al.
Placental angioarchitecture in monochorionic twin pregnancies: relationship to fetal growth, fetofetal transfusion syndrome, and pregnancy outcome
Am J Obstet Gynecol
(2000) - et al.
Placental sharing, birthweight discordance and vascular anastomoses in monochorionic diamniotic twin placentas
Am J Obstet Gynecol
(2007) - et al.
Twin anemia-polycythemia sequence in two monochorionic twin pairs without oligo-polyhydramnios sequence
Placenta
(2007) - et al.
Placental vascular anastomoses visualized during fetoscopic laser surgery in severe mid-trimester twin-twin transfusion syndrome
Placenta
(2001) - et al.
Placental types and twin-twin transfusion syndrome
Am J Obstet Gynecol
(2002) - et al.
Monochorionic twins and twin-twin transfusion syndrome: the protective role of arterio-arterial anastomoses
Placenta
(2002) - et al.
The pregnancy and long-term neurodevelopmental outcome of monochorionic diamniotic twin gestations: a multicenter prospective cohort study from the first trimester onward
Am J Obstet Gynecol
(2009) - et al.
Residual vascular communications in twin-twin transfusion syndrome treated with sequential laser surgery: frequency and clinical implications
Placenta
(2010)
Residual anastomoses in twin-to-twin transfusion syndrome treated with selective fetoscopic laser surgery: localization, size, and consequences
Am J Obstet Gynecol
Intertwin anastomoses in monochorionic placentas after fetoscopic laser coagulation for twin-to-twin transfusion syndrome: is there more than meets the eye?
Am J Obstet Gynecol
Prevalence and management of late fetal complications following successful selective laser coagulation of chorionic plate anastomoses in twin-to-twin transfusion syndrome
Am J Obstet Gynecol
Arterio-arterial vascular anastomoses in monochorionic twin placentas with and without twin anemia-polycythemia sequence
Placenta
Clinical outcome in neonates with twin anemia-polycythemia sequence
Am J Obstet Gynecol
Clinical outcome and placental characteristics of monochorionic diamniotic twin pairs with early- and late-onset discordant growth
Am J Obstet Gynecol
Perinatal outcome of forty-nine pregnancies complicated by acardiac twinning
Am J Obstet Gynecol
The outcome of twin reversed arterial perfusion sequence diagnosed in the first trimester
Am J Obstet Gynecol
Monoamniotic-versus diamniotic-monochorionic twin placentas: anastomoses and twin-twin transfusion syndrome
Am J Obstet Gynecol
Improved perinatal survival of monoamniotic twins with intensive inpatient monitoring
Am J Obstet Gynecol
Central nervous system abnormalities assessed with prenatal magnetic resonance imaging
Obstet Gynecol
Stage-based treatment of twin-twin transfusion syndrome
Am J Obstet Gynecol
The value of middle cerebral artery peak systolic velocity in the diagnosis of fetal anemia after intrauterine death of one monochorionic twin
Am J Obstet Gynecol
Long-term neurodevelopmental outcome in twin-to-twin transfusion syndrome
Am J Obstet Gynecol
Unequal placental sharing and birth weight discordance in monochorionic diamniotic twins
Am J Obstet Gynecol
Fetal growth after laser therapy for twin-twin transfusion syndrome
Am J Obstet Gynecol
Selective photocoagulation of communicating vessels in the treatment of monochorionic twins with selective growth retardation
Am J Obstet Gynecol
Pregnancy and infant outcome of 80 consecutive cord coagulations in monochorionic multiple pregnancies: a prospective follow-up study
Am J Obstet Gynecol
The hidden mortality of monochorionic twin pregnancies
Br J Obstet Gynaecol
Optimum timing for planned delivery of uncomplicated monochorionic and dichorionic twin pregnancies
Obstet Gynecol
Monochorionic diamniotic twin pregnancies: natural history and risk stratification
Fetal Diagn Ther
Co-twin prognosis after single fetal death: a systematic review and meta-analysis
Obstet Gynecol
Twin-twin transfusion syndrome during the 2nd trimester is associated with small intertwin hemoglobin differences
Fetal Diagn Ther
Paradoxic activation of the renin-angiotensin system in twin-twin transfusion syndrome: an explanation for cardiovascular disturbances in the recipient
Pediatr Res
Interventions for twin-twin transfusion syndrome: a Cochrane review
Ultrasound Obstet Gynecol
The efficacy of Quintero staging system to assess severity of twin-twin transfusion syndrome treated with laser therapy: a systematic review with meta-analysis
Am J Perinatol
Comparison of donor and recipient outcomes following laser therapy performed for twin-twin transfusion syndrome: a meta-analysis and review of literature
Am J Perinatol
Cited by (202)
Maternal hemodynamic evaluation in monochorionic twin pregnancy complicated by twin-to-twin transfusion syndrome treated with fetoscopic laser surgery
2024, American Journal of Obstetrics and Gynecology MFM
J.D. is the recipient of a grant of Fonds voor Wetenschappelijk Onderzoek Vlaanderen (FWO; 1.8.012.07.N.02).
The authors report no conflict of interest.
Reprints not available from the authors.