As the previous user said, you should be given answers for the possible cause of your stillbirth and possible health problems you may have, by autopsy analysis of the baby and your general check up.
However, in most of the cases of stillbirths, the cause stays undetermined, even after an extensive testing and autopsy.
Some of the possible causes are the following:
chromosomal abnormalities which are incompatibile with life, birth defects, diabetes and high blood pressure in mother, bleeding infectious diseases within the fetus, spina bifida (congenital defect of spinal cord), umbilical-cord problems, placenta separating too soon from the womb wall, physical trauma, use of alcohol, drugs, nicotine, but the most common are placenta problems, chromosomal errors in the baby and mother's health issues.
Best wishes!
Marija