What causes omphalocele and is it a highrisk pregnancy?

Yes. Yes it is a high risk prenancy and requires good prenatal care. No, we do not know what causes omphalocele although there are several genetic syndromes which are not hereditary and usually discovered post natally such as hemi hypertrophy and or beckwith weidemann.
Unknown, yes. The cause of an omphalocele is not known. It should be considered a high risk pregnancy.