What does it mean if i tested positive for trisomy 18? should i be worried?

Confusing question: Are you saying you have T18, or your pregnancy is positive for T18. The first response would not be possible. The second is worrisome. Those with any trisomy have birth defects, many of which are life threatening.Few with T18 live past a year of age.

Depends on test: I am thinking you had a Triple or Quadruple Screen done, and it came back positive for trisomy. If so, it does not mean the baby has it, but that the risk of having it is increased. It is a screening test, meant to screen out the majority of women who are low risk and need no further testing. A positive test doesn't mean the baby has it, just that you need to consider further testing to find out.

Edwards syndrome: One must assume that you are pregnant and that testing related to your unborn baby. Further assessment is warranted. However, if this is accurate - Trisomy 18 is a serious Chromosomal disorder.