What Should Be The Endometrium Size To Conceive?

I am 30yr old, my hight is 4ft 10inc n my weight is 48kg. I have a 7weeks missed abortion last year. Now am taking treatment for getting pregnant my endometrial size was 4.9 on the 9th day of period my dr.was refered progaynova 4tablets a day and it increase 7.4 on the 14th day but dr.says it should grow more so i want ur opinion on this and i also want to know the howmuch should it increase?