Am heartbroken that friend's child has mayer rokitansky kuster hauser syndrome. How could that have been prevented?

Couldn't be.. Mayer rokitansky kuster hauser (mrkh) syndrome is a structural defect of a female fetus that occurs during fetal development. The cause is unknown and no specific genetic abnormality for this defect has been identified. Mrkh occurence is unpredictable and cannot be prevented. For most of the girls affected, there is treatment available.
It cant be prevented. Mrkh syndrome is the lack of vaginal development. It can be relatively easily corrected by surgeons with advanced urogynecologic skills. Like the vast majority of developmental abnormalities, there is no way to predict or prevent this condition.