Dog behavior - pooping in house

Question
My 2 year old male Akita has been doign his business in the house lately. I let him out in the morning for quite some time and he goes out again at lunch time, but when I get home around 4:30 he has gone number 2 on the floor. I've noticed that he has not been doing his business outside as much as before either. I recently had him boarded for the Thanksgiving holiday and ever since I brought him home he has been doing this. He has been boarded before and has never pooped on the floor after I have brought him home from the kennels. I'm not sure what is going on with him. I am also 7 months pregnant and someone told me that may have a factor, but why would he wait until I am 7 months along to start behaving in this manner? I'm just confused and need to know why he has been pooping in the house. He doesn't pee in the house, just poops and only while no one is home and only since I picked him up after the holiday.

Answer
It appears that something occurred to this dog while he was in boarding and it must be related to his elimination behavior.  It may be another dog challenged him, a sight or sound that was unfamiliar, etc., anything can create a fear response in a dog in ONE SECOND without your ever noticing it yourself.  Find another kennel.

First, you must go out with the dog and OBSERVE his appropriate elimination, then praise and reward him.  You will SEE if he has developed any superstitious or avoidant behavior regarding elimination outdoors.  IF YOU SEE THIS, repost with the exact description of what he is doing and we will tackle the fear response he has apparently acquired.  However, YOUR PRESENCE may eliminate his fear; if this is the case, and if you accompany him for two weeks every night, this problem should self extinguish.  

Meanwhile, pick the poop up IN HIS SIGHT and carry it outdoors to the place you want him to eliminate.  Express your joy when it is in its appropriate place; I know, this sounds bizarre, but it works.

I won't say it's impossible for the dog to be responding to your hormonal surge during pregnancy because I HAVE SEEN THIS many times in my practice.  But it's highly unlikely this is the catalyst.