Fetal lung size after thoracoamniotic shunting reflects survival in primary fetal hydrothorax with hydrops.

AIM: To assess the role of lung size and abnormal Doppler findings in the umbilical artery (UA) in determining the outcomes of fetuses with primary fetal hydrothorax (FHT) associated with hydrops who underwent thoracoamniotic shunting (TAS).

METHODS: This was a retrospective study at a single center. We included cases of primary FHT with hydrops who underwent TAS at our hospital between 2004 and 2016. We assessed the relationship between mortality until 28 days after birth and ultrasound findings, including absent or reversed end-diastolic velocity (AREDV) in the UA and the lung-to-thorax transverse area ratio (LTR), before and after TAS.

RESULTS: Forty-one cases of primary FHT with hydrops underwent TAS. The median (range) gestational age at TAS was 28.5 (19.3-33.8) weeks. Bilateral pleural effusion was observed in 39 cases (95.1%). Among the 41 cases, 19 (46.4%) survived, 11 (26.8%) died in utero, and 11 (26.8%) died in the neonatal period. AREDV in the UA before and after TAS were not associated with mortality (P = 0.32 and 0.47, respectively). The odds ratio for mortality in LTR 0.2-0.3 before TAS was 0.62 (vs LTR < 0.2, P = 0.45) and that in LTR 0.2-0.3 and > 0.3 after TAS were 0.27 and 0.06, respectively (vs LTR < 0.2, P for trend <0.01).

CONCLUSION: A larger LTR after TAS was significantly associated with a better prognosis in hydropic primary FHT. The fetal lung size after the procedure may be a prognostic factor of primary FHT.