Can my boxer get pregnant while not in heat?

Question
My boxer faith is over a year and half. She had her first heat when she was a
year old. It came time for her 2nd heat and it never came... its been about 2
months since she was suppose to come into heat and she still hasn't?! Should
i be worried?? She was very very sick as a puppies. I had to tube feed her for
her first two months, every two hours night and day. She finally started
growing when she was about 6 months old. She looks like she is about 8
months old but she is actually getting close to 2 years old. Could that have
anything to do with her not coming into heat again??
 Also, I had heard that some dogs never come into heat (or that their owners
notice) and end up pregnant.. is that true??

Answer
She can not get pregnant if she is not in heat. She wouldn't even allow a male to mount her.

She should have a heat cycle every 5-6 months.

Low weight and over weight, lack of a heat cycle, indicates a thyroid condition.

Take her to your vet and have her thyroid checked. They will draw blood from an artery in her neck and test it. It is not expensive.

If she has a thyroid condition/imbalance, I recommend Pala-Tech chewables. They are only about $10 for 180 count bottle.

Most vets carry it, but some don't.