What are the risks of a thrombophilia during pregnancy?

Yes. The risk of a blood clot would be the greatest issue. A miscarriage is a complication of thrombophilias also. Treatment can be successful with low dose Aspirin and subclinical heparin.
Loss of pregnancy. Intrauterine fetal death is a complication of thrombophilia during pregnancy; in addition to the usual complications of thrombosis and embolism that occur during the non-pregnant state.