Birthfather unknown

Please if anyone could give us some advice on this it would be most helpful. We were contacted through friends of a birthmom wanting adoption for her baby.She is pregnant almost 3 months.I have talked to the birthmom and we get along extremely well.The problem is the birthfather.She is saying he is unknown,which could be true.I am just terrified that a birthfather will step forward later on.I was told in Maryland all that needs to be done is her name ran in a newspaper ad through the courts.Once so many number of days pass and the father does not come forward his rights will be terminated.Is this true? Are there any loop holes which a birthfather could possibly use in order to gain custody of the baby.I have been extremely worried over this whole situation.I can only go by what the birthmom says,but as i read other messages on this adoption forum you cannot believe everything that is told to you.Some people are saying i should steer clear of this situation.We have wanted to adopt for years and if there is the slighest chance of adopting we feel we should risk it.I strongly feel this situation was brought to us for a reason.God for some reason wanted us to be a part of this situation.I am just wondering how many adoptions are done without the birthfather being known.If anyone has any advice on this please let us know we would be thankful.