Chlamydia during pregnancy?

So I've heard alot of females coming out positive for chlaymdia when they check for STDs during pregnancy I am one of those people. I'm 98% sure I didn't actually have it. The doctor herself told me it's very common for those to come back false positive and reading about alot of other females coming out for chlamydia makes me think is this actually a thing in pregnancy? I wonder what can cause the false positive.