"Luckily, none of his Marines were hurt," she said.
The night after she learned of her husband's death, Kait gave birth to Michael Everett Wyatt,
7 pounds, 11 ounces, named after the patron saint of the military.
The pregnancy had been planned in case Wyatt didn't return from Afghanistan.
"We wanted to have something tangible, a physical expression of our love," she said, "just in case there wasn't another opportunity."
Wyatt had recorded passages of the Dr. Seuss book "Oh, the Places You'll Go!" During her pregnancy, Kait aimed her iPod speaker at her stomach; when she brought the baby home from the hospital, she played the recording softly to help him sleep.
Before Kait left the hospital with her baby, a casualty assistance officer decorated her home, including placing an "It's a Boy" sign on the front lawn.
"He made sure that Michael got the kind of homecoming that his father would have wanted," Kait said, her voice trembling. She paused, unable to speak.
Waiting at home was a receiving blanket for the baby, in Marine colors and with the Three-Five logo.
Under a bitterly cold sky, Cpl. Wyatt was buried Jan. 7 at Arlington National Cemetery in a section reserved for the fallen from Iraq and Afghanistan.
At the funeral service, Kait told of a conversation she and her husband had before he deployed about what she should do if he was killed in Afghanistan.
Kait said she told Derek that she would never remarry. He pulled the car to the side of the road, she said, looked directly at her and made her promise that she would again find love in her life.
"He told me the only thing he wanted in life was for me to be happy," Kait said.
As she spoke, there were tears in the eyes of the mourners, including Marines with the 3rd Battalion, 5th Marine Regiment, which is still fighting for a faraway place known as Sangin.
Perry also reported from Bethesda, Md.