* Q1 loss widens; rev beats est

* Says FDA indicates deficiencies at facility addressed

* Shares up 17 pct after the bell

April 30 (Reuters) - AMAG Pharmaceuticals Inc (AMAG.O: Quote, Profile, Research) said the U.S. health regulator informed it that the deficiencies noted at a facility manufacturing its experimental anemia drug has been adequately addressed, driving its shares up 17 percent after the bell.

The biopharmaceutical company, which also reported a wider-than-expected loss for the first quarter, had received a second complete response letter for the approval of the anemia drug, Feraheme, in December 2008.

In the letter, the Food and Drug Administration asked for additional data to clarify a specific chemistry, manufacturing and controls issue and required the resolution of certain deficiencies in the company's manufacturing facility.

For the first quarter, AMAG reported a net loss of $26.4 million, $1.55 a share, compared with net loss of $9.3 million, or 55 cents a share, a year ago.

Revenue rose 56 percent to $956,000, but this growth was offset by a 129 percent jump in operating costs and expenses to $28.9 million.

Analysts were expecting the company to post a loss of $1.30 a share, on revenue of 360,000.

Shares of the Lexington, Massachusetts-based company rose 17 percent to $52.50 after the bell. They had closed at $44.85 Thursday on Nasdaq. (Reporting by Anuradha Ramanathan in Bangalore; Editing by Himani Sarkar)