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, reports the Associated Press.

An anti-abortion group filed a complaint with the board, alleging that Dr. LeRoy Carhart was negligent in his care of woman who had a late-term abortion at a Germantown clinic.

Maryland's chief medical examiner has determined that 29-year-old Jennifer McKenna-Morbelli of New York died Feb. 7 of natural causes, including from a rare complication related to childbirth.

The board of physicians will seek a response from Carhart and review medical records, according to the AP. The board will then decided to pursue a full investigation or to close the case.

A spokesman for the Montgomery County Police Department has said investigators are awaiting the full autopsy report.

Morbelli's death has become a rallying point for anti-abortion activists who have denounced the Germantown Reproductive Health Services clinic, run by Carhart.

Carhart is featured in a documentary film, "After Tiller," as one of four doctors in the U.S. who perform legal late-term abortions. The title refers to George Tiller, an abortion doctor in Kansas who was assassinated in 2009 by an anti-abortion activist.