To assess the use and efficacy of in‐utero pleurodesis for experimental treatment of bilateral fetal chylothorax.

This was a study of 78 fetuses with bilateral pleural effusion referred to three tertiary referral centers in Taiwan between 2005 and 2009. Fetuses were karyotyped following amniocentesis and the lymphocyte ratio in the pleural effusion was determined following thoracocentesis. Forty‐nine (62.8%) fetuses had a normal karyotype and were recognized to have fetal chylothorax; of these, 45 underwent intrapleural injection of 0.1KE OK‐432 per side per treatment. We evaluated clinical (hydrops vs. no hydrops) and genetic (mutations in the reported lymphedema‐associated loci: VEGFR3, PTPN11, FOXC2, ITGA9) parameters, as well as treatment outcome. Long‐term survival was defined as survival to 1 year of age.

The overall long‐term survival rate (LSR) was 35.6% (16/45); the LSR for non‐hydropic fetuses was 66.7% (12/18) and for hydropic fetuses it was 14.8% (4/27). If we included only fetuses with onset of the condition in the second trimester, excluding those with onset in the third trimester, the LSR decreased to 29.4% (10/34). Notably, 29.6% (8/27) of hydropic fetuses had mutations in three of the four loci examined.

OK‐432 pleurodesis appeared to be an experimental alternative to the gold‐standard technique of thoracoamniotic shunting in non‐hydropic fetal chylothorax. In hydropic fetuses, pleurodesis appeared less effective. Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.