Controlled amnioreduction for twin-to-twin transfusion syndrome

Abstract

Background: Twin-to-twin transfusion syndrome (TTTS) is a severe condition causing preterm delivery, fetal death, and neurodevelopmental disorders. This study presents a data-based controlled amnioreduction (AR) protocol composed of sequential amniodrainage in treatment of TTTS.

Methods: A total of 18 procedures were performed in 11 TTTS pregnancies at 17 to 34 weeks of gestation. The amniotic pressure was measured along with sequential removal of the amniotic fluid, 500 mL each step. The umbilical artery systolic/diastolic (S/D) ratio for each twin was measured pre- and post-AR. Long-term neurodevelopmental outcomes of all TTTS survivors were evaluated from parental answers to a phone survey.

Results: The amniotic pressure decreased exponentially with the increased volume of removed amniotic fluid until a plateau was obtained. Changes of the S/D ratio between pre- and post-AR procedure did not reveal a clear tendency. The survival rate was 86.4% although 91% of all twins were at Quintero stage III. Long-term neurodevelopment outcomes in the 19 surviving twins were 68.4% optimal, 26.3% suboptimal, and 5.3% abnormal.

Conclusion: The controlled AR procedure resulted in a relatively high rate of twin survival with favorable long-term neurodevelopment outcomes.

Keywords: S/D ratio; amniotic fluid; amniotic pressure; long-term neurodevelopment; twin pregnancies; twin survival.

Figure 1.

Schematic description of the controlled amnioreduction procedure. The three-way stopcock is in position to measure the amniotic pressure with the manometer. Turning the stopcock 90° counterclockwise allows for amniodrainage into the bag.

Figure 2.

The amniotic pressure versus the drained volume of amniotic fluid during the controlled AR procedure. Solid curves represent completed procedures; Dash curves represent interrupted procedures. The different colors represent the different patients listed in Table 1.

Figure 3.

Pre-AR (squares) and post-AR (circles) amniotic pressures at the gestation week the controlled AR was performed. The arrows represent the direction of change due to the controlled AR. The black dashed curves represent the 5% and 95% percentiles of normal amniotic pressures during singleton pregnancies. The colored symbols and curves represent the same patients as shown in Figure 2.

Figure 4.

Pre-AR (squares) and post-AR (circles) umbilical artery S/D ratios in each of the fetuses at the gestation week the controlled AR was performed. The arrows represent the direction of change due to the controlled AR. The black dashed curves represent the 5% and 95% percentiles of normal S/D ratios during singleton pregnancies. The colored symbols and curves represent the same patients as shown in Figure 2.