Can Citalopram Cause Delay In Period?

Hi, may I answer your health queries right now ? Please type your query here...Hi, I've been taking 20mg of citalopram for the last month & I'm now 4 days late for my period. I have felt sick as well so I done a pregnancy test which came back negative, so my question is does citalopram delay menstruation or can citalopram give a false negative?