All I know that at some point at around 12 weeks your placecnta takes over with the hormones. I don't think that it would be safe to keep taking them without the advise of the Doctor. However, if you don't have insurance, you can apply for emergency medicaid which covers maternity care and then you could go to the doctor earlier. But in the mean time if you are going to wait that long to go back to the doctor then at least call her and ask her if its safe.