Hi I Am Due For My Last Dose Of Twinrix

Hi I am due for my last dose of twinrix (had 1st dose 2nd a month later and due to have one now 6mths later). My husband and I have decided we would like to have another baby (our third). How long do I need to wait before trying after having my last dose of twinrix. I fell pregnant with both my other children within a few months of going off the pill but I was a lot younger 27 and 29 i am now 36 in July.