I think she would have gotten an abortion or given the baby up. I also believe her and Derek would not be together.
They/She was not ready for a baby.

Mer would have probably commited suicide or something. She was so unstable back then. She wouldn't have been able to raise a child, let alone face any other responsibilities..

Derek loves Meredith and Meredith loves Derek. Meredith's pregancy would make her choice between Derek and Finn easier because she would have still chosen Derek since he would have been the father of her child. Their wedding would have been beautiful and they would raise their children together as one big happy family. Not only would they be married with children, they would be living in their house on Derek's land. Derek and Meredith love each other and there is no doubt in my mind that they would raise their children together as a happily narried couple. She wants to be Dr. and Dr. Shepherd. Meredith wants a future with Derek and he wants a future with her. Meredith would never have given her child with Derek up because she loves Derek and Derek loves her.

Derek and Meredith are so in love with each other. Meredith's pregnancy would have meant that she would be Mrs. Derek Shepherd and Meredith would be Meredith Shepherd not Meredith Grey. Her pregnancy with Derek's child meant that she would have still chosen Derek because she loves him and they would have a happy family. Their wedding would be what they want and Meredith would no longer be dark and twisty because she would have the life she has wanted since they met. Instead of living in Ellis's house or Meredith's house, they would be living in their own house on his land with their children.

Derek loves Meredith and Meredith loves Derek. Meredith's pregancy would make her choice between Derek and Finn easier because she would have still chosen Derek since he would have been the father of her child. Their wedding would have been beautiful and they would raise their children together as one big happy family. Not only would they be married with children, they would be living in their house on Derek's land. Derek and Meredith love each other and there is no doubt in my mind that they would raise their children together as a happily narried couple. She wants to be Dr. and Dr. Shepherd. Meredith wants a future with Derek and he wants a future with her. Meredith would never have given her child with Derek up because she loves Derek and Derek loves her.