Air Force Major Adrianna Vorderbruggen is the first openly gay woman to be killed in action, the Daily Beast news website reported, citing a Department of Defense official.
Six American troops, including Vorderbruggen, were killed on December 21 when a suicide bomber on a motorbike struck their patrol in the deadliest attack on US forces this year.
Facebook postings on December 22 by Vorderbruggen's loved ones mourned her death on December 21 and sent condolences to her wife Heather and son Jacob. The family lives near Washington, D.C., where the couple was married in June 2012, the year after the military's "don't ask, don't tell" policy for gays was repealed.
"We do find comfort in knowing that Heather and Jacob are no longer in the shadows and will be extended the rights and protections due any American military family as they move through this incredibly difficult period in their lives," said the posting from Military Partners and Families Coalition.
Bagram, around 40 km (25 miles) north of Kabul, is one of the main bases for the remaining 9,800 UStroops in Afghanistan, after international troops ended combat operations last year.
The victims included New York City Detective Joseph Lemm, a 15-year veteran of the NYPD who also volunteered in the US Air National Guard and was on his third deployment to war zones.