Preoperative factors associated with donor twin demise in 1602 pregnancies complicated by twin-twin transfusion syndrome.

Abstract

To identify preoperative risk factors associated with postlaser fetal death of the donor twin in a large cohort of pregnancies complicated by twin-twin transfusion syndrome (TTTS). This retrospective cohort study of prospectively collected data included monochorionic diamniotic pregnancies complicated by TTTS that underwent laser surgery between March 2006 and May 2024 at two specialized referral centers. Patients underwent a comprehensive ultrasound examination, including fetal Doppler evaluation, to assign a Quintero stage and to obtain the middle cerebral artery (MCA) peak systolic velocity (PSV) for each twin within 24 h before laser surgery. An isolated elevation of the donor MCA-PSV was defined as having an MCA-PSV > 1.5 multiples of the median (MoM) in the absence of twin anemia-polycythemia sequence (TAPS). TAPS was defined as donor MCA-PSV > 1.5 MoM and recipient MCA-PSV < 1.0 MoM or intertwin MCA-PSV difference of > 0.5 MoM. Patients underwent postoperative ultrasound the day after surgery to document cardiac activity in each twin. Univariate logistic and multivariable Poisson (Zou's method) regression models were used to estimate the odds ratio and adjusted relative risk (aRR) for donor twin demise, adjusted for TAPS, TTTS stage, selective fetal growth restriction (sFGR), donor MCA pulsatility index < 10^th percentile, gestational age < 18 weeks at surgery and other risk factors. Fetal demise of the donor twin was noted in 14.3% (229/1602) of the study population. Preoperative isolated elevation of donor MCA-PSV conferred the highest aRR of any risk factor for postlaser donor fetal demise (aRR, 2.69 (95% CI, 1.91-3.81); P < 0.001) compared with Stage-III TTTS (aRR, 2.34 (95% CI, 1.36-4.02); P = 0.002), MCA pulsatility index < 10^th percentile (aRR, 1.91 (95% CI, 1.48-2.46); P < 0.001), velamentous cord insertion in the donor twin (aRR, 1.86 (95% CI, 1.43-2.41); P < 0.001), TAPS (aRR, 1.63 (95% CI, 1.19-2.23); P = 0.001), gestational age < 18 weeks at laser surgery (aRR, 1.59 (95% CI, 1.21-2.08); P = 0.001) and sFGR (aRR, 1.58 (95% CI, 1.19-2.07); P = 0.001). The observed frequency of fetal demise of the donor twin increased with each additional concomitant risk factor included. Isolated elevation of donor MCA-PSV prior to laser surgery for TTTS conferred the highest aRR for donor fetal demise among risk factors including TAPS, TTTS staging, sFGR and other covariates. This risk increased progressively when more than one risk factor was present in pregnancies complicated by TTTS. © 2025 International Society of Ultrasound in Obstetrics and Gynecology.