UnitedHealth Group (NYSE: UNH) shares tumbled 5.65% in pre-market trading on Thursday following the release of its first-quarter earnings report and a significant downward revision to its full-year profit guidance. The healthcare giant's results fell short of Wall Street expectations, sparking concerns about rising medical costs and their impact on the company's profitability.

UnitedHealth reported adjusted earnings per share of $7.20 for the first quarter, missing analysts' estimates of $7.29. Revenue came in at $109.58 billion, also falling short of the expected $111.60 billion. The company's medical care ratio, a key metric measuring the percentage of premiums spent on medical care, rose to 84.8%, indicating higher-than-anticipated healthcare utilization.

In a move that further rattled investors, UnitedHealth substantially lowered its full-year 2025 profit forecast. The company now expects adjusted earnings of $26 to $26.50 per share, down from its previous guidance of $29.50 to $30 per share. This significant reduction suggests that UnitedHealth anticipates the pressure from elevated medical costs to persist throughout the year. The revised outlook falls well below the Wall Street consensus of $29.73 per share, highlighting the magnitude of the challenges facing the company in the current healthcare landscape.