UnitedHealth reports earnings later this month, and a strong showing could help ensure the stock's recent rally continues.Health insurer UnitedHealth Group (UNH 1.95%) reports its third-quarter earnings results later this month, on Oct. 28. It could be a pivotal report for the company, which indicates whether the stock's recent rally continues or if it goes back into a tailspin.The healthcare company has faced challenges with rising medical costs in recent quarters, which resulted in it missing expectations ...