Dear Editor,

The three excellent articles on twin to twin transfusion syndrome (TTTS) provide futher important data for clinical decisions and parental counselling. We would like to comment on the paper by Cincotta et al.[1]

We are interested in the incidence of hydrops and absence of end diastolic velocity of the umbilical artery in the cohort and their correlation with outcome. A recent study of 33 pregnancies with TTTS by Mari et al[2] showed that the presence of hydrops of the recipient and absence of the end-diastolic velocity of the umbilical artery in one of the twins were associated with poor prognosis.

In contrast with the findings of Mari et al[2] the Brisbane group did not find any significant difference in the mean weight between the donor and recipient twins. We wondered whether this is due to efficacy of obstetrics interventions, a less severe nature of the TTT or a shorter duration between time of diagnosis and delivery. We believe that the data should have included a comparison between the donor and recipient twins in both short term and longer-term outcomes. Interestingly Mari et al found 3 of 28 recipient twins had periventricular leukomalacia compared with none of the 23 donor live born twins although the difference was not significant.

The authors should state how many of the babies in their cohort were less than 27 weeks' gestation at birth as one study of 112 cases of TTTS showed a drop in survival from 70% at 27 weeks to less than 25% at 26 weeks or earlier.[3]

We also note that 8 babies in the cohort had chronic lung disease. The findings by Shinwell et al published in the same issue of the ADC emphasised yet again the worrisome association between post natal steroids with increased cerebral palsy[4]; it would therefore be useful to know how many of the babies in the TTTS group had post natal steroids and whether these babies were over represented in those with cerebral palsy.

It would also be interesting to know what percentage of the cohort were IUGR. We believe that TTTS could provide an ideal situation to test Barker’s hypothesis of in utero programming for morbidities during later life.[5]

THHG Koh MA FRCPCH FRACP
Senior Staff Specialist in Neonatal Paediatrics
Collie L RN
Neonatal Research Nurse
Budge D RN
Neonatal Research Nurse
Regional NICU, Kirwan Hospital
Townsville, Great Barrier Reef
Queensland 4817 Australia
fax 0747730320

References
(1) Cincotta RB, Gray PH, Phythian G, Rogers YM, Chan FY. Long term outcome of twin-twin transfusion syndrome. Arch Dis Child Fetal Neonatal Ed 2000;83:F171-6.

(2) Mari G, Detti L, Oz U, Abuhamad AZ. Long-term outcome in twin-twin transfusion syndrome treated with serial aggressive amnioreduction. Am J Obstet Gynecol 2000;183:211-17.

(3) Dickinson JE, Evans SF. Obstetric and perinatal outcomes from the Australian and New Zealand Twin-Twin Syndrome Registry. Am J Obstet Gynecol 2000;182:706-12.

(4) Shinwell ES, Karplus M, Reich D, Weintraub Z, Blazer S, Bader D, Yurman S, Dolfin T, Kogan A, Dollberg S, Arbel E, Goldberg M, Gur I, Naor N, Sirota L, Mogilner S, Zaritsky A, Barak M, Gottfried. Early postnatal dexamethasone treatment and increased incidence of cerebral palsy. Arch Dis Child Fetal Neonatal Ed 2000;83:F177-F81.

(5) Barker DJ. In utero programming of cardiovascular disease. Theriogenology. 2000;53:555-74.