Outcome of monochorionic twin pregnancies with moderate amniotic fluid discordance adjoining twin-twin transfusion syndrome

US Evaluation of Twin Pregnancies: Importance of Chorionicity and Amnionicity

The twin birth rate is increasing in the United States. Twin pregnancies can be dichorionic or monochorionic (MC). MC twins account for 20% of twin pregnancies but 30% of all-cause pregnancy-related complications. This article describes the imaging findings that establish chorionicity and amnionicity. Ideally, these are established in the first trimester when accuracy is high, but they can also be determined later in pregnancy. Complications unique to MC twin pregnancy include twin-twin transfusion syndrome, twin anemia polycythemia sequence, twin reversed arterial perfusion sequence, and selective fetal growth restriction. The US features, staging systems, and management of these complications are reviewed, and the consequences of MC twin demise are illustrated. Ongoing surveillance for these conditions starts at 16 weeks gestation. Monoamniotic (MA) twins are a small subset of MC twins. In addition to all of the MC complications, specific MA complications include cord entanglement and conjoined twinning. Radiologists must be able to determine chorionicity and amnionicity and should be aware of potential complications so that patients may be referred to appropriate regional specialized centers. A proposed algorithm for referral to specialized fetal treatment centers is outlined. Online supplemental material is available for this article. ^©RSNA, 2019.

Modified underlying cardiac disease severity in twin-twin transfusion syndrome

Twin-twin transfusion syndrome or related conditions affect fetal loading. We report monochorionic-diamniotic twins. Twin 1 had Ebstein anomaly with mild tricuspid regurgitation (TR) and slightly thickened tricuspid valve leaflets with plastering. Twin 2 had tricuspid valve dysplasia (with abnormal thickening but without plastering) with moderate TR and mild right atrial dilatation. After birth, the severity of TR was greatly reduced in the recipient but increased in the donor. Therefore, intravascular volume change which was due to twin-twin transfusion syndrome seemed to affect the severity of the valvar disease in fetuses. This case suggests that the intrinsic severity of fetal tricuspid valvular disease may be overestimated in the recipient and underestimated in the donor twin. These factors need to be taken into consideration in clinical decision-making.

Fetoscopic laser photocoagulation for twin-twin transfusion syndrome

The aim of this study was to review fetoscopic laser photocoagulation (FLP), which ablates placental vascular anastomoses to treat twin–twin transfusion syndrome (TTTS). A review of studies reporting on the procedures, outcomes, complications and nonconventional applications of FLP for TTTS was conducted. FLP has been established as the primary treatment for monochorionic twin pregnancy associated with TTTS at 16–26 weeks. FLP is the only therapy that directly addresses the underlying pathophysiology. The recent technique modification of FLP, referred to as the ‘Solomon technique’, induces selective coagulation to connect the anastomoses ablation sites and has been introduced to reduce residual anastomoses. The perinatal survival following FLP improved significantly with advances in the technique after its introduction. The recent survival rates of both twins and at least one twin are 70% and more than 90%, respectively. However, there is still an 11–14% risk of long‐term neurodevelopment impairment. The premature rupture of membranes that leads to preterm labor is a common complication after FLP. FLP is a valuable treatment option for feto‐fetal transfusion syndrome in triplets and for TTTS after 26 weeks. FLP for selective intrauterine growth restriction may be potentially beneficial when accompanied by abnormal Doppler findings and oligohydramnios. FLP is the optimal treatment option for TTTS at 16–26 weeks of gestation. FLP appears to be applicable in triplets, TTTS after 26 weeks and cases of selective intrauterine growth restriction with abnormal Doppler findings and oligohydramnios. FLP is the most common and successful fetal intervention. Improvement in the neurodevelopmental outcomes after FLP is a future focus.

Midtrimester isolated oligohydramnios in monochorionic diamniotic multiple gestations. J Matern Fetal Neonatal Med 2017;32:590-596. [PMID: 28965437 DOI: 10.1080/14767058.2017.1387530]

OBJECTIVE

To describe the natural history and perinatal outcomes of monochorionic diamniotic twins with midtrimester isolated oligohydramnios (iOligo).

MATERIALS AND METHODS

We performed a retrospective study of iOligo patients who were initially referred for the management of evolving twin-twin transfusion syndrome (TTTS) or selective intrauterine growth restriction (sIUGR). iOligo was defined as a maximum vertical pocket of amniotic fluid of ≤2 cm in the iOligo twin's sac and normal fluid level (>2 and <8 cm) in the co-twin's sac. "Group A" patients did not subsequently develop TTTS or sIUGR Type II (umbilical artery persistent absent or reversed end-diastolic flow), and "Group B" patients did develop TTTS or sIUGR Type II. Results are reported as median (range).

RESULTS

Of the 828 patients with complicated monochorionic twin gestations referred for possible TTTS or sIUGR, 36 (4.3%) were initially diagnosed with iOligo. After initial consultation, two patients terminated and one was lost to follow-up, resulting in a final study population of 33. Group A had 10 patients (30.3%) and Group B had 23 patients (69.7%). In Group A, nine of the 10 were expectantly managed, resulting in a median gestational age (GA) at delivery of 34.7 (18.0-36.4) weeks, a 30-day perinatal survival of at-least-one twin of 88.9% (8/9), and dual 30-day survivors in 8/9 (88.9%). In Group B, 12 (52.2%) developed TTTS and 11 (47.8%) developed sIUGR Type II. Fifteen Group B patients had laser surgery, resulting in a median GA at delivery of 33.7 (26.4-37.1) weeks, a 30-day perinatal survival of at-least-one twin of 100% (15/15), and dual survivorship of 46.7% (7/15).

CONCLUSIONS

Our findings show that the majority of patients with midtrimester iOligo have fetal growth restriction of the affected twin and subsequently progress to TTTS or sIUGR Type II.

Fetoscopic laser photocoagulation for amniotic fluid discordance bordering on twin-twin transfusion syndrome: Feasibility, perinatal and long-term outcomes

AIM

This study investigated the feasibility and safety of fetoscopic laser photocoagulation (FLP) for amniotic fluid discordance (AFD) bordering on twin-twin transfusion syndrome (TTTS) with an absent or reverse end-diastolic velocity (AREDV) in the umbilical artery (UA), and evaluated the perinatal and long-term outcomes.

METHODS

A prospective intervention study was performed between 20 + 0 and 25 + 6 weeks of gestation (UMIN000004165). AFD bordering on TTTS was defined as maximum vertical pocket (MVP) of amniotic fluid in one twin's sac ≤3 cm and amniotic fluid MVP in the other twin's sac ≥7 cm excluding TTTS. Neurodevelopmental outcome was evaluated at 6 months and at 3 years of age.

RESULTS

Eleven women were treated without complications between September 2010 and July 2011. In all cases amnioinfusion was required, with a median surgical time of 70 min. There were nine cases of selective intrauterine growth restriction in which the growth discordant rate was >25%. The survival rates of the donor and recipient twins were 27.3% (3/11) and 100% (11/11), respectively. None of the surviving donor twins and two of the 11 recipient twins had hemiplegia at 6 months of age. One additional recipient twin had developmental delay at 3 years of age.

CONCLUSIONS

Fetoscopic laser photocoagulation for AFD bordering on TTTS with AREDV in the UA was feasible without complications but frequently resulted in donor twin death and a high survival rate of the recipient twin, albeit with neurodevelopmental abnormalities in some cases. FLP does not seem to be a promising treatment option for AFD bordering on TTTS.