Analysis of fetal growth after laser therapy in twin-to-twin transfusion syndrome

Objective. The purpose of this study was to evaluate fetal growth patterns after laser therapy in twin-to-twin transfusion syndrome (TTTS). Methods. All cases with delivery after 24 weeks from pregnancies complicated by TTTS treated by laser therapy between January 1999 and September 2004 were included. Fetal biometric parameters and estimated fetal weight were measured by sonography at least twice before laser therapy and twice after laser therapy. The interval between sonographic measurements was at least 2 weeks. The study population was divided into group I, which consisted of pregnancies with 2 liveborn neonates, and group II, which consisted of pregnancies resulting in only I liveborn neonate. The z scores for biometric measurements were calculated in all cases accordingly and compared for each twin across gestational age by analysis of variance and between groups by a t test. In group I, the intertwin discordance was also assessed, and analysis of variance was used to compare mean values across gestational age. Results Ninety-eight cases with 51 single and 47 double liveborn neonates were included. Across time, z scores of the recipients significantly decreased, whereas there was no change in z scores of the donors. The z scores were not statistically different between groups. There was a significant decrease in fetal discordance after laser therapy in group I. Conclusions. The fetal growth pattern in TTTS can change after laser treatment. There is a slowdown in the recipient growth and maintained growth in the donor twin. Both mechanisms lead to a decrease in intertwin discordance.