it is very unlikely that you did not get an std while having unprotected sex with your boyfriend if he had chlamydia at that time as well. if you have not had sex with him since you became pregnant and you tested negative i'm sure you can do the math.
how contagious is chlamydia? my now ex bf tested positive and i am negative. my bf and i were pregnant i lost the baby but not before i got tested for all std's. which all came back negative. my bf and i did not have sex after we found out i was pregnant but just last week he called and told me he was positive for chlamydia. how likely is it that i didn't get it if he had it when we had unprotected sex for 3 months?