GERMANTOWN, Md. (AP) — The Maryland Board of Physicians has opened a preliminary investigation into the death of a woman who was treated at an abortion clinic in Germantown.

An anti-abortion group filed a complaint with the board, alleging that Dr. LeRoy Carhart was negligent in his care of the 29-year-old woman. Carhart is known for providing late-term abortions, and his clinic is the site of frequent protests by abortion opponents.

The Maryland medical examiner’s office determined that the woman died of natural causes, including a rare complication related to childbirth in which amniotic fluid was pushed into her bloodstream.

The board will ask for a response from Carhart and review medical records. The board will then decide whether to pursue a full investigation or to close the case.

(Copyright 2013 by The Associated Press. All Rights Reserved.)