I have sytus inersus, dextrocardia with vsd closer. i am in 12th week of pregnancy. what precaution shall i take?

Talk to your OB: If you are pregnant you should be seeing an OB to to deal with any potential complications, get prenatal care, and increase the odds of successfully completing your pregnancy (healthy baby, healthy mom). This includes making sure your doctor knows about any previous health problems (e.g. like VSD). They will tell you what precautions are needed, if any. They may ge thelp from 'high risk' OB doc.