ushers syndrome and pregnancy

I wonder if you can help with some information about women who have Usher Syndrome and are pregnant.....  Some of them noticed that their vision field deteriorated since they became pregnant and some of them didn't.

I remember attending a lecturer given about those issues at the 8th Deafblind conference in Melbourne, Australia last year.... I cannot remember the name of the lecturer. He was saying something about excessive vitamin K had to be avoided during pregnancy? Or was it to take extra vitamin K and avoid vitamin A? Or was there something else that women should take that would be beneficial during pregnancy?  

[Houman Vosoghi, MD]

This should be discussed with a geneticist.  Usher syndrome is in the spectrum of Retinitis Pigmentosa for the eyes but as far as the changes that may take place with pregnancy I'm not sure about (beyond my area of knowledge).  I couldn't find any studies with a quick search either on the topic.  Genetic counselling however is a must.  The following link will summarize findings related to vitamins and supplements but I would be carefull about recommending high doses of vitamin A to anyone yet alone pregnant women given potential side effects and not enough evidence that it helps.

http://emedicine.medscape.com/article/1227488-treatment

HV