WellPoint says lower enrollment and rising medical costs have hurt its bottom line. Revenue grew 4% to $15.42 billion in the quarter. The company reported net income of $856.5 million, or $2.53 a share, for the three months ended March 31, compared to net income of $926.6 million or $2.44 a share, a year ago.  In recent quarters, most health insurers have been recording robust profits as patients postponed care in a sluggish economy. But WellPoint had struggled with higher-than-expected claims from a Medicare plan in Northern California last year, which hurt earnings and rattled investor confidence in the company according to a recent story in the Los Angeles Times.