Dilated to 2cm

How many moms are dilated any? I went in for my normal doctor apt today and the doctor checked me. He think I lost my mucus plug and I'm dilated to 2 cm with mild contractions (not many). He admitted me to be monitored and sent me home on procardia to stop any pre labor. Anyone else having anything similar? I'm 33 weeks with twin girls. He wants me to make it to 35 weeks at least.