The relationship between preoperative fetal head circumference and 2-year cognitive performance after laser surgery for twin-twin transfusion syndrome

Objective: To determine the relationship between preoperative fetal head circumference (HC) and cognitive performance among children treated with laser surgery for twin-twin transfusion syndrome (TTTS). Methods: Donor and recipient twin HCs were measured preoperatively (16–26 weeks' gestation) and at 2 years corrected age. Multilevel multivariate regression models were used to test pregnancy and child-level risk factors for lower Battelle Developmental Inventory Second Edition (BDI-2) scores. A repeated-measures ANOVA was used to examine HC growth among recipients and donors between preoperative and 2 years. Results: Ninety-nine children were evaluated. The average BDI-2 score for the cohort was 101.4 (SD = 12.2). After controlling for covariates, larger preoperative HC percentiles were significantly associated with an increase in total BDI-2 scores (β = 0.29; P < 0.001), where a 12.5% increase in preoperative HC percentile was associated with 1-point increase in total BDI-2 score. The mean recipient and donor twin HC percentiles preoperatively and at age 2 years were 51^st percentile vs 20^th percentile (P =.050) and 60^th percentile vs 49^th percentile (P =.676), respectively. Conclusion: Smaller preoperative HC percentiles identified children at risk of lower, but still within normal range, total BDI-2 scores. The discordance in HC percentiles between the donor and recipient twin decreased after laser surgery.