Without knowing much details about the case it is very difficult for me to either tell you the cause or the treatment for the same. It could be that uncontrolled sugars are the cause or maybe some infection because of the sugars. It could be because of some problems like Thrombophilias or some problem inside the uterine cavity. Am sorry sitting so far away, I really cant be of much help to you.
I dont want to make false promises, neither do I wish to play god. I however can tell you this that there is always a reason why such things happen and we need to find out that cause. Once that is done, its always easy. Yes there are a small percentage of cases where no cause is found but there again nature usually by itself takes care of things and corrects itself.Do come in if you like and I will do my best to help you.