A condition once considered uniformly fatal before or shortly after birth may now be survivable with a prenatal fluid intervention — a shift that challenges longstanding clinical nihilism around severe fetal kidney failure and reframes what neonatal survival looks like in an era of advanced dialysis and transplant medicine.
The RAFT trial, a prospective nonrandomized study conducted across 13 US fetal therapy centers from 2018 to 2025, enrolled 32 maternal-fetal pairs with anhydramnios — the complete absence of amniotic fluid — arising from fetal kidney failure diagnosed before 22 weeks' gestation. Critically, the trial excluded the most-studied subgroup (bilateral renal agenesis) and focused on other causes of fetal renal failure, a population with far less evidence behind it. Beginning before 26 weeks' gestation, participants received serial transamniotic infusions of isotonic fluid to restore amniotic volume and allow fetal lung development to proceed. The live birth rate reached 91% (29 of 32), with a median gestational age at delivery of approximately 34 weeks. No unexpected serious maternal adverse events were reported. The primary endpoint — neonatal survival for at least 14 days with dialysis access placed — was met in a meaningful proportion of infants, with secondary outcomes including survival to discharge and kidney transplant candidacy also reported.
Historically, anhydramnios from renal failure carried near-certain lethality through pulmonary hypoplasia, the lungs failing to develop without the mechanical stimulus of amniotic fluid. Earlier small case series for bilateral renal agenesis hinted at the amnioinfusion concept's viability, but the RAFT data represent the most rigorous prospective evidence yet for a broader etiological category. The 91% live birth figure is striking, though the nonrandomized design means there is no contemporaneous control group for direct comparison. Surviving infants will face lifelong kidney disease management — dialysis dependency and eventual transplant — so these findings reframe parental counseling rather than eliminate medical complexity. This is an incremental but clinically consequential step: a once-counseled-lethal diagnosis now warrants a survival-oriented conversation.