Doctor prescribe me cardiomagnyl 75mg for trombofilia,took it first weeks pregnancy,and then i took every other day,can it cause any problem for baby?

No clinical trials: for clear data/answer/guidance. As an aspirin based (baby aspirin strength: 75 mg/pill) anti-clotting agent, it is generally not recommended during either 1st or 3rd trimester of pregnancy. However, there is no definitive answer or guidance, thus taking/non-taking is always about individual issues/situation & (hopefully) informed individual choice(s) about pros and cons of the choices.