The effects of drug abuse during pregnancy have long been documented. The use and abuse of these substances have been known to cause diseases for the unborn children, ranging from cocaine addiction to severe birth defects. Physicians have therefore strongly advised pregnant women to refrain from using drugs, especially restricted ones such as marijuana and cocaine.

             Research has proven that substances like marijuana and cocaine damage short term memory, distorts perceptions, impairs complex motor skills, alters the heart rate, can lead to severe anxiety, and can cause paranoia and lethargy. All these effects present significant problems even to people who are healthy. The risks are compounded for women who are pregnant.

             Cocaine use is much more dangerous than marijuana, since the former's effects are felt immediately. These effects also disappear quickly. Small amounts of up to 100 mg can give the user a sense of euphoria. While marijuana produces a sedating effect, cocaine users experience heightened sensations. Many users become energetic and talkative, and will experience a decreased need for sleep or food.

             In addition to passing the drug into their unborn child's system, cocaine users thus deprive their body of significant nutrients needed by a growing fetus. This could lead to disrupted fetal development, in the form of birth defects. Disruptions in brain development at this significant stage can also lead to cognitive problems or learning disabilities for the child. In the euphoric state, the mother is also likely to engage in behavior that is risky, both for her and her unborn child. These include sexual behavior, which exposes the fetus to diseases, and reckless activities which may result in accidents.

             Because of these proven dangers, several states have enacted "fetal rights" instruments designed to protect unborn children from their mothers' substance abuse problems.