Use of marijuana during pregnancy might increase the risk of having a baby that is smaller at birth. It might also slightly increase the risk of stillbirth. New research also suggests that there might be a link between maternal marijuana use during pregnancy and mental health, social issues and sleep problems in children. Using marijuana during pregnancy can also harm your health. The American College of Obstetricians and Gynecologists recommends against using marijuana during pregnancy.

Marijuana is a plant that contains delta-9-tetrahydrocannabinol (THC) and other chemicals that affect the body. When marijuana is smoked or eaten, these chemicals cross the placenta. Research suggests that using marijuana at least weekly during pregnancy increases the risk of giving birth to a baby with a low birth weight — less than 5 1/2 pounds (2,500 grams). While research suggests a small increase in the risk of stillbirth as well, the results couldn't be adjusted to exclude the effects of tobacco use. Further research is needed.

Use of marijuana during pregnancy can also make you dizzy and alter your judgment, putting you at risk of falls or other injury. Smoking marijuana can damage your lungs and cause breathing problems too.

If you're considering pregnancy, stop using marijuana before you become pregnant. If you're having trouble with substance use, ask your health care provider for advice or resources to help you quit.