Feto-feto-fetal transfusion syndrome in monozygotic monochorionic triamniotic triplets: vascular evaluation by a cast model

Expectant management in type II selective intrauterine growth restriction and abnormal cord insertion in monochorionic twins

OBJECTIVE

To assess perinatal outcome in type II monochorionic (MC) diamniotic twin pregnancies (DA) affected by selective intrauterine growth restriction (sIUGR) and abnormal cord insertion managed expectantly.

METHODS

A prospective longitudinal study from June 2008 and July 2011 on 24 MCDA sIUGR twins. sIUGR was defined as estimated fetal weight below the 10th percentile in one twin and was classified into three groups based on umbilical artery (UA) Doppler diastolic flow (I: presence; II: constantly absent/reverse (AEDF/ARED); III: intermittently absent or reverse). Marginal cord insertion was defined as insertion within 2 cm of the placental disc edge, and velamentous insertion as a cord insertion into the fetal membranes. Expectant management was chosen in these twins, and absent or reverse A wave in the ductus venosus (DV) was a criterion for delivery. Neonatal outcome was available for all twins delivered. Pathological examination and vascular cast of placentas were performed in all cases.

RESULTS

Fourteen twin pregnancies were type II sIUGR, and ten presented an abnormal umbilical cord insertion. Median gestational age (GA) at diagnosis of sIUGR was 18 weeks' gestation (range 16-20 weeks), and all sIUGR co-twins showed AEDF of UA at a median gestational age of 20 weeks (range 18-22 weeks). Median gestational age at delivery was 30 weeks (range 28-34 weeks) with a median birth weight of 1285 g (range 307-1725 g). pH at birth and base excess (BE) were normal in all IUGR co-twin (pH>7.10, median BE 5.5); Apgar score at 5 min was >7. Perinatal outcome was favorable in all cases. Placental pathological examination confirmed the marginal insertion of the umbilical cord and the absence of anastomosis between the two portions of umbilical insertion.

CONCLUSIONS

This study highlights that expectant management for sIUGR type II twins with or without an abnormal cord insertion should be a valid option to time delivery for these fetuses as shown by the favorable neonatal outcome.

Deep-hidden anastomoses in monochorionic twin placentae are harmless

OBJECTIVES

Our objective was to identify the clinical consequences of deep-hidden anastomoses that occur underneath the placental surface.

METHODS

Twelve placentae that underwent intrauterine laser ablation of placental anastomoses for twin-twin transfusion syndrome (TTTS) and 14 non-TTTS controls were investigated for deep-hidden anastomoses. Additionally, we investigated the inter-twin haemoglobin differences as an indicator for fetofetal transfusion. Placentae were divided into four groups: TTTS placentae without residual chorionic-plate anastomoses without deep-hidden anastomoses (group 1) and with deep-hidden anastomoses (group 2), and non-TTTS placentae with chorionic-plate anastomoses without deep-hidden anastomoses (group 3) and with deep-hidden anastomoses (group 4).

RESULTS

Deep-hidden anastomoses were identified in 58% (7/12) of the TTTS placentae after laser surgery and in 64% (9/14) of the non-TTTS placentae. Groups 1 and 2 had equal inter-twin haemoglobin differences: medians 1.4 and 1.2 gr/dL, respectively (p = 0.48). In group 3, the median inter-twin haemoglobin difference without deep-hidden anastomoses was 2.6 gr/dL (group 3) and with deep-hidden anastomoses (group 4) it was 5.1 gr/dL (p = 0.26).

CONCLUSION

Both comparisons imply that deep-hidden anastomoses did not cause any additional increase in Hb difference. In conclusion, haematological and additional hemodynamical analysis show that deep-hidden anastomoses are likely to occur without any clinical consequences.

Comparison of Pregnancy Course and Outcome with Color and Radiographic Angiography of the Placenta in a Monochorionic Triplet Pregnancy

A patient with spontaneous monochorionic (MC) triamniotic triplet pregnancy developed symptoms of feto-fetal-transfusion-syndrome (FFTS) at 18 weeks of gestation with one donor (oligohydramnios) and one receptor (polyhydramnios) triplet. The patient "received" a diet enriched with proteins. Amniotic-fluid volume returned to normal after 24 weeks. At 32 weeks, a Cesarean section was performed due to intra-uterine growth restriction of the donor triplet. Post partum color injection and computer angiograms showed arterio-arterial (AA) anastomoses between all triplets. Deep arterio-venous (AV) anastomoses between the two triplets who had demonstrated with oligo- and polyhydramnios between 18 and 26 weeks were revealed by computer angiography that were not seen by placental color angiogram. Detailed analysis of placental vascular communications by use of color injection angiogram of the chorionic plate and computer angiogram demonstrating deep anastomoses beneath the chorionic plate helps to understand the individual pathophysiology and clinical course in patients with FFTS, which is even more complex in MC triplet compared to MC twin pregnancies.