However, another study conducted in the 1980s found no differences in weaning, growth or mental development between children exposed to marijuana during breast-feeding, and those not exposed, according to a 2009 review. No studies have examined the possible long-term effects of marijuana exposure during breast-feeding. The 2009 review said that there is concern that THC could alter brain cell metabolism as the baby's brain grows in the first month of life.
Mendez agreed, saying that the risk might be particularly concerning for a premature baby.
"For babies born premature, we know they're under more severe neurological stress," Mendez said. "I can't imagine how marijuana would help that at all," Mendez said. "Why would you want to take any risk?"
Mendez added that a drug that alters mood and perception, as marijuana can, may also affect people's ability to care for their children. "This is at a time when your baby is completely dependent on you," he said.
Smoking in general is also discouraged for new parents because it is linked with an increased risk of conditions such as asthma and sudden infant death syndrome (SIDS), the AAP says.
Still, breast-feeding has many known benefits, including a reduced risk of SIDS, leading some sources to advocate taking a more nuanced approach to marijuana use during breast-feeding, as opposed to a complete ban. LactMed, a database from the National Institutes of Health that has information on drug and chemicals during breastfeeding, says that "marijuana use should be minimized or avoided by nursing mothers." But the database also notes that there is little evidence of serious harm, so "it appears preferable to encourage mothers who use marijuana to continue breastfeeding while minimizing infant exposure to marijuana smoke and reducing marijuana use."
A 2012 review on the topic concludes by saying: "There are no studies that support breastfeeding and use of marijuana. However, with conflicting results [of studies], further studies and case-by-case considerations are warranted in cases of occasional use."
Some studies have linked marijuana use in pregnancy to an increased risk of having a low-birth weight, small for gestational age, or premature baby. Some studies also suggest a link between marijuana use during pregnancy and the child having attention and learning problems later in life.
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