What causes neonatal abstinence syndrome?
Almost every drug passes from the mother’s blood stream through the placenta to the fetus. Illicit substances that cause drug dependence and addiction in the mother also cause the fetus to become addicted. At birth, the baby’s dependence on the substance continues. However, since the drug is no longer available, the baby’s central nervous system becomes overstimulated causing the symptoms of withdrawal. Some drugs are more likely to cause NAS than others, but nearly all have some effect on the baby. Opiates, such as heroin and methadone, cause withdrawal in over half of babies exposed prenatally. Cocaine may cause some withdrawal, but the main symptoms in the baby are due to the toxic effects of the drug itself. Other drugs such as amphetamines, barbiturates, and narcotics can also cause withdrawal. Alcohol use causes withdrawal in the baby, as well as a group of problems including birth defects called fetal alcohol spectrum disorders (FASDs).
