It is safe to use vix during pregnancy?

Vicks? yes. Did you mean to say Vicks cough drops? Those contain menthol as a topical treatment for the throat. There is no medical reason why you can't use that during pregnancy. Like all medications in pregnancy, however, you should only use it for the time that you really need it. The only over the counter "medications" that should be taken for the whole pregnancy are prenatal vitamins and/or folic acid.