My dog seems to have dog aggression. Have you ever dealt with instances of owner's pregnancy causing behavior problems in dogs? Any training suggestions?

I came across your website while researching information on dog on dog aggression, and hope you can help me! My husband and I have female two dogs -- a 9-1/2 year old mutt and an almost 5-year old lab mix. The lab mix (Koda) was raised in the house with the older dog (Sadie), and both dogs were spayed as puppies. Sadie has always been very submissive, while we realized very early on that Koda has a very dominant personality. While training Koda as a puppy we've taken steps to ensure that we're the alphas in the pack, including crate training her (she still sleeps in her crate in a room by herself) and making her sit and stay before giving her food. She has never shown any aggression towards us, or any other people, but occassionally when she was younger would attack Sadie over food, toys, etc. To stop this we've tried to ensure that there's never anything they can fight over -- the food is stored in the garage, the dogs are fed separately (using gates to keep them in separate rooms and out of sight of each other), and they have multiples of toys so that each one can have their own. Also, when they are in the house with us and there are toys available, we keep Koda leashed to the furniture as recommended by a previous trainer, so that she cannot try to take the toys away from Sadie or bully Sadie over them. There have been instances where Koda becomes jealous if Sadie gets more attention, so we make sure to show Koda more attention any time they are both together.

Generally the two have gotten along, although there have been occassional fights over the years because of the above mentioned things, they were never bad and it was easy to stop them. However, Koda has become increasingly aggressive towards Sadie over the last several months, and has attacked her for no apparent reason very seriously, although we've so far been fortunate to not have any permanent damage to either dog. She has also become very menacing to Sadie in her body language, to the point where Sadie will sometimes not even be in the same room with Koda and acts afraid to go outside with her at the same time. The most recent fight was particularly bad -- my husband was barely able to pray Koda's jaws apart to get Sadie's throat out of her mouth! (Luckily, she's never attempted to turn on us during a fight, although we usually don't try to pull them apart at the biting ends!)

I am currently 7 months pregnant and worried that her aggressive behavior will continue towards my child, even though she's never shown any aggression towards humans... Also, I cannot help but wonder if the fights are happening over some sense of protection (or jealousy) of me, since they always occur when I'm in the room and Sadie is between me and Koda (even if I'm not actually paying attention to Sadie at the time), and the behavior started this summer around the time I became pregnant. I've tried researching aggressive dog behavior and pregnant owners, but haven't had any luck so far. My husband and I love both of these dogs dearly and we don't want to have to get rid of Koda because of her aggression, but this behavior just cannot continue once there's a baby added to the mix!

Have you ever dealt with instances of owner's pregnancy causing behavior problems in dogs? And do you have any training suggestions that could help us get Koda's behavior under control before the baby is born? Any help you can give would be greatly appreciated!

Thanks,
Rachael