Thanks for your query.I am Dr.SharonBaisil.
From your history,i feel that it is fungal infection
that is bothering you.it can,present like this.you can use monistat 7
cream available in markets.Its totally safe for your pregnancy
and baby.Apply the cream on,the itchy area.And remember to keep your panties dry.moisture in panties can increase fungal infection.hope I have been helpful to you.feel free to ask any of your doubts.