Doxycycline is the category of tetracyclines. I took a tetracycline medication until I was about two weeks pregnant. Stop taking them!!!! They can cause side effects but you are so early there is a huge chance that it did NOT harm your baby. What you need to do is inform your obstetrician that you were on them and they will set you up with a medication consultation with another doctor and when you are further along they will do an ultrasound to see if any effects are there. The chance is really low. I was ona very strong ttetracycline and I just had my scan last week and everything is fine. They checked from head to toe on the scan and measured everything. Just like me, your doctor should have warned you not to get pregnant while on it, and mine never did! The possible side effects for tetracyclines are shortened limbs or blackening of the teeth when the child is older but the chances are veryyyy low because you are so early! I spent weeks worrying I hurt the baby but I took them early on too. You are probably fine, but you will need that medication consult and "fetal monitoring" (frequent ultrasounds to check on the growth of the baby).