Fetoscopic laser surgery in twin anemia polycythemia sequence: effect on fetal growth.

OBJECTIVE

To evaluate fetal growth patterns in spontaneous twin anemia-polycythemia sequence (TAPS) pregnancies treated with fetoscopic laser surgery.

METHOD: This retrospective cohort study included all consecutive spontaneous TAPS pregnancies treated with laser surgery at the Leiden University Medical Center between 2002 and 2024. We evaluated the changes in estimated fetal weight (EFW) and presence of fetal growth restriction (FGR; EFW <10th centile) in TAPS donors and recipients after laser, and presence of small for gestational age (SGA; birth weight < 10th centile).

RESULTS

Twenty-two spontaneous TAPS twin pairs were analyzed. At the time of laser surgery, FGR was more common in donors than in recipients (43% (9/21) vs. 5% (1/21), p = 0.023). Following laser treatment, growth centiles remained stable in most donors (77%, 17/22), improved in 5% (1/22), while declined in 18% (4/22). Among recipients, 64% (14/22) had stable growth, whereas 36% (8/22) experienced a decrease in growth centile and none showed improvement. At birth, SGA was observed in 55% (12/22) of donors and 36% (8/22) of recipients.

CONCLUSION

Donor twins are frequently growth restricted prior to laser surgery but generally maintain or improve growth afterward. In contrast, one-third of recipients demonstrate post-laser growth decline, likely reflecting the cessation of intertwin transfusion.