Abstract

OBJECTIVES: to ascertain the incidence of antenatally diagnosed brain injuries in twin pregnancies complicated by twin to twin transfusion syndrome (TTTS) and to quantify the perinatal mortality, morbidity and long-term neurodevelopmental outcomes of these fetuses. METHODS: Medline, Embase, Clinicaltrials.gov and Cochrane Library databases were searched. Inclusion criteria were studies reporting on brain abnormalities diagnosed antenatally in twin pregnancies complicated by TTTS. The primary outcome was the incidence of prenatal brain abnormalities. The secondary outcomes were intrauterine demise (IUD), neonatal death, termination of pregnancy (TOP) and long-term morbidity. All these outcomes were explored in the overall population of fetuses with antenatal diagnosis of brain abnormalities. Sub-group analysis according to: type of treatment, gestational age and Quintero stage at diagnosis and/or treatment, co-twin death was planned. Meta-analyses of proportions were used to combine data and reported pooled proportion and their 95% confidence intervals (CI). RESULTS: Thirteen studies including 1573 cases of TTTS and 88 fetuses with an antenatal diagnosis of brain abnormalities were included in the systematic review. The meta-analysis included only studies reporting on brain abnormalities in twin pregnancies complicated by TTTS cases and treated with laser. Overall, brain injuries occurred in 2.2% of fetuses (eight studies (52/2410 fetuses)). These brain abnormalities were reported in 1.03% and 0.82% of recipients or donors, respectively. These abnormalities were mainly ischemic lesions (30.4%, 95%CI 19.1-43), followed by destructive lesions (23.9%, 95%CI 13.7-35.9), ventriculomegaly (19.9%, 95% CI 10.6-31.3) and hemorrhagic (15.3%, 95%CI 7.1-25.8). Spontaneous IUD occurred in 13.4% (95%CI 5.1-24.8) of fetuses, while TOP was chosen by parents in 53.5% (95%CI 38.9-67.8) cases. Neonatal death was reported only by three studies with an incidence of 15.4% (95%CI 2.8-35.4). Finally, only two studies reported on composite morbidity with 20.4% of morbidity reported overall (95%CI 2.5-49.4) which occurred in 29.7% and 20.4% of the recipient and donor fetuses, respectively. Due to the small numbers, only composite morbidity was analyzed and no information on neonatal intensive care unit admission, respiratory distress syndrome or other long-term outcomes such as neurodevelopmental delay or cerebral palsy could be reliably retrieved. CONCLUSIONS: The overall incidence of antenatally diagnosed fetal brain abnormalities in fetuses from twin pregnancies complicated by TTTS treated with laser is around 2%, mainly ischemic (30.4%) in nature. TOP was chosen by parents in almost half of the cases (53.5%). No information could be retrieved on morbidity outcomes, highlighting the urgent need for long-term follow up studies of these children.