While rare and extremely life threatening it has happend and actually happend to a women in 2012!
The following is from a reputable news source here in the US.
Miracle Baby Born During Rare ‘Abdominal Pregnancy’
Credit CBS 2NEW YORK(CBSNewYork)*— A Staten Island woman recently gave birth to a*miracle baby. The newborn developed in her abdomen instead of her womb.The baby and her mother made medical history three months ago when they showed up at Richmond University Medical Center in Staten Island for what was supposed to be a routine c-section.But, Dr Michael Moretti told CBS 2′s Dr Max Gomez that when Sylvia Ortiz arrived for the procedure she had a surprise in store for him.“It was an abdominal pregnancy, or a rupture in the uterus with a large opening in its cavity,” he explained.This happens when the embryo escapes the fallopian tubes and lodges itself in the mother’s abdomen. The embryo grows on the abdomen wall, outside of the uterus, and can cause major trouble for the mother.“The risks would be catastrophic bleeding, massive bleeding from the big blood vessels, and the placenta area in the abdomen. It could cause shock, organ damage, and death from hemorrhage,” he said.A team of doctors and nurses were assembled, and during the procedure Sylvia lost nearly all of her blood volume. It took forty units of blood, and two operations, over a course of twenty-four hours to control the bleeding. Sylvia didn’t wake up for three days.