Several therapies are available for TTTS and include amnioreduction, laser ablation of vascular placental anastomoses, selective feticide, and septosromy. Described further in Chapter 11 (p. 230), amnioreduction describes needle drainage of excess amnionic fluid. Septostomy is intentionally creating a hole in the dividing amnionic membrane but has largely been abandoned as treatment (Society for Maternal-Fetal Medicine, 2013). Comparative data from randomized trials for some of these other techniques are discussed below.
The Eurofetus trial included 142 women with severe TTTS diagnosed before 26 weeks. Participants were randomly assigned to laser ablation of vascular anastomoses or to serial amnioreduction (Senat, 2004). A higher survival rate to age 6 months for at least one twin was found in pregnancies undergoing laser ablation-76 versus 51 percent, respectively. Moreover, analyses of randomized studies confirm better neonatal outcomes with laser therapy compared with selective amnioreduction (Roberts, 2008; Rossi, 2008, 2009). In contrast, Crombleholme and associates (2007), in a randomized trial of 42 women, found equivalent rates of 30-day survival of one or both twins treated with either amnioreduction or selective fetoscopic laser ablation-75 versus 65 percent, respectively. Furthermore, evaluation of twins from the Eurofetus trial through 6 years of age did not demonstrate an additional survival benefit beyond 6 months or improved neurological outcomes in those treated with laser (Salomon, 2010). At this time, laser ablation of anastomoses is preferred for severe TTTS (stages II-IV). Optimal therapy for stage I disease is controversial.
FIGURE 45-21 A. Sonogram of stage I ms at 19 weeks' gestation. Oligohydramnios in the donor twin sac causes the membrane to essentially wrap around the "stuck twin" and suspend it from the anterior uterine wall. B. In this same pregnancy, hydramnios is seen in the recipient twin sac. The measured pocket exceeds 10 cm. C. Stage II ms in a donor twin at 17 weeks' gestation. Color Doppler highlights the arteries that outline the fetal bladder, which contains no urine.
After laser therapy, close ongoing surveillance is necessary.
Robyr and colleagues (2006) reported that a fourth of 101 pregnancies treated with laser required additional invasive therapy because of either recurrent TTTS, or middle cerebral artery (MCA) Doppler evidence of anemia or polycythemia. Recently, in a comparison of selective laser ablation of individual anastomoses versus ablation of the entire surface of the chorionic plate along the vascular equator, Baschat and coworkers (2013) found that equatorial photocoagulation reduced the likelihood of recurrence.
Selective fetal reduction has generally been considered if severe amnionic luid and growth disturbances develop before 20 weeks. In such cases, both fetuses typically will die without intervention. Any substance injected into one twin may afect the other twin because of shared circulations. hus, for the fetus chosen for reduction, feticidal techniques include methods that occlude the umbilical vein or umbilical cord of using radiofrequency ablation, fetoscopic ligation, or coagulation with laser, monopolar, or bipolar energy (Challis, 1999; Chang, 2009; Parra-Cordero, 2016). Even after these procedures, however, the risks to the remaining fetus are still appreciable (Rossi, 2009). This topic is further discussed on page 891.