Cancer and complications from pregnancy were the top causes of long term disability claims filed with Unum Group Corp. in 2009.

Normal pregnancy was the leading cause of short term disability claims at Unum, Chattanooga, Tenn. (NYSE:UNM), the company says.

Unum timed the release of the report to coincide with Disability Insurance Awareness Month, which started May 1.

Cancer and pregnancy complications each accounted for about 12% of Unum’s group LTD claims in 2009, about the same as in 2007.

On the group STD side, normal pregnancy caused 23% of the claims, up from 21% in 2007. Injuries other than back injuries triggered 9.5% of the STD claims, roughly the same as in 2007.

Return-to-work rates for claimants with many conditions have improved dramatically in recent years, Unum says.

The return-to-work rate increased to 53% in 2008, from 47% in 2001, for insureds with breast cancer, and to 34%, from 28%, for insureds with prostate cancer.

For insureds with colon cancer, the return-to-work rate increased to 33%, from 23%.