How much of a possibility is it that my baby will be deformed in some way if i was on Accutane?

I started taking Accutane 60mg every day since september last year, i was also on a contraceptive. i have just found out that i am 18 weeks pregnant, i took the accutane from 3 months and then stopped for about 3 months due to healt insurance issues. I have had a scan and the doc says my baby is physically fine bt have to do tests to determine if the chromosomes of the baby are normal. please help with an answer