Health plan enrollment has stabilized at CIGNA Corp.

CIGNA, Philadelphia, is reporting $352 million in net income for the first quarter on $4.1 billion in revenue, compared with $436 million in net income on $4.3 billion in revenue for the first quarter of 2005.

Net income was down partly because acceleration of a deferred gain pumped up net income during the first quarter of 2005, CIGNA says.

Health insurance earnings fell 24%, to $156 million, but medical membership held steady at about 9 million.

In the fourth quarter of 2005, medical membership fell 6.2%.

In other earnings news:

- Lincoln National Corp., Philadelphia, is reporting $221 million in net income for the first quarter on $1.4 billion in revenue, up from $179 million in net income on $1.3 billion in revenue for the first quarter of 2005.

The performance of variable annuity products was particularly strong, and deposits in the Lincoln Choice Plus multi-manager VA contract increased 38%, Lincoln says.

- American Equity Investment Life Holding Company, West Des Moines, Iowa, is reporting $4 million in net income for the first quarter on $223 million in revenue, compared with $13 million in net income on $99 million in revenue for the first quarter of 2005.

Accounting for the derivatives and other tools American Equity uses to support its equity indexed annuity operation causes dramatic fluctuations in net results, the company says.

Operating income, which excludes the effects of market value changes in derivatives and some other factors, increased to $18 million, from $13 million.

American Equity has been getting about 96% of its sales from the sale of EIA contracts.

Sales fell to $565 million in the first quarter, down 16% from the total for the first quarter of 2005, American Equity says.