Marijuana

• According to the American Pregnancy Association (APA) marijuana increases the amount of carbon dioxide and carbon monoxide present in the blood of a pregnant woman, lowering the amount of oxygen supplied to the baby, and increasing the baby's risk of developmental and behavioral problems.
  
  

Cocaine

• The APA explains that the use of cocaine during pregnancy increases the likelihood of a birth defect and may also leave the child dependent on the substance, experiencing withdrawal symptoms such as muscle spasms, sleeplessness and feeding difficulties.
  
  

Heroin

• The APA further reports that the use of heroin during pregnancy leads to premature birth and low-birth weight, but can cause more serious problems such as hypoglycemia (low blood sugar), intracranial hemorrhages (brain bleeding) and withdrawal symptoms.
  
  

Hallucinogens

• The NIH describes that the abuse of hallucinogens during pregnancy, such as LSD and PCP, has the potential to cause brain damage to the baby or cause the baby to develop poor muscle control and, when used frequently, hallucinogens can cause the baby to suffer withdrawal symptoms.
  
  

Methamphetamine

• The NIH warns that when under the influence of methamphetamine, the drug can cause an increase in the baby's heart rate similar to that which the mother experiences, can reduce the level of oxygen supplied to the baby, can increase the chance of premature labor and low-birth weight, and cause the baby to suffer withdrawal symptoms.