Hemoglobinopathies can be detected with a blood test called hemoglobin electrophoresis. It is advisable to do this test before getting pregnant though it can be done during pregnancy as well.
If the test results are positive and show that you are a carrier then the next step is to have the partner tested. If the partner is not a carrier, then the risk of having a child with the disorder is extremely low.
In case the partner also is a carrier, then the risk of having a child with a hemoglobinopathy is 1 in 4. The risk of having a child who is a carrier is 1 in 2.
In this case, amniocentesis or chorionic villus sampling (CVS) can be done to check if the fetus is a carrier or affected. Therefore, it is advisable to know the results of your HB electrophoresis before getting pregnant.