Has anyone else been told the umbilical cord is not in the center of the placenta?

I was told the umbilical cord is attached to the side or corner of the placenta rather than the center where it should be. That's all the doctor said and I didn't know what it meant or even thought of it until I googled it when I went home. It seems it can cause low birth weight babies, pre term labor, and delivery issues. My baby is already measuring smaller than normal, so I'm really concerned and going to call the nurse ASAP. Anyone experienced this or been told the same? I'm due April 26th.