I had anembryonic pregnancy, what causes it?

Doctor, I'm 20 years old, it's been four months since my period did not go down and I got pregnant. Soon afterwards I started with a bleeding and in my first pregnancy I had an anembryonic pregnancy, what caused it to happen? I had never heard of it. Thanks in advance for your opinion ... hugs!
Expert answer:

An embryonic pregnancy occurs due to malformations or reabsorption of the fetus at a very early stage of pregnancy when the baby and the placenta are a single solid mass formed by few cells, not an explanation or very definite causes for it, usually this is because the baby that would be generated from this gestation would be malformed, so nature itself takes care of eliminating a baby that would not be normal.