There are numerous state and federal laws designed to protect against misuse and diversion of prescription drugs that apply to patients' behavior, physicians' prescribing practices, and dispensing.
Punishing women who use drugs during pregnancy deters them from seeking prenatal care and entering drug treatment programs, and the relevant policies may unfairly target poor or minority women.
It is unconstitutional--and unethical--for physicians to participate in evidence-gathering against pregnant women suspected of being addicted to illegal substances without informing them of their constitutional rights or gaining their informed consent.
When a pregnant woman is knowingly causing harm to her unborn child, there are various legal interventions that can be taken to protect the rights if the fetus.