A chemical pregnancy is when the embryo stops developing after it has implanted. Most of the time they go completely undetected. You could have a positive test one day and negatives after that. This is why there is no such thing as a "false positive" pregnancy test, because all tests detect hCG, which can only be released from an implanted embryo (or fertility drugs). I've had two chemical pregnancies, myself, on record. The only reason we found out was because we were with a fertility specialist who was monitoring my blood and ultrasounds once a week. There is no way to know whether or not it will happen. If it does happen, though, it is generally because the embryo stopped dividing cells or the egg or sperm had a problem. It doesn't mean there will be future problems, however, so no need to fear.
at 8:45 PM on Apr. 13, 2009