Help!!! important !!! If you have ever had twins ( other ,multiples )?

I went to the dr for a check up today and he said my babies are growing well but because of something about (too thin, irregular) umbilical cords they will be small and most likely early, i am due on dec 11 and he said i should feel lucky to get past nov. so my question is , if you have had any multiples how early were they , size, how long did they need to stay in the hospital? Were there any major complications?