A study published in the Maternal and Child Health Journal has found that children whose mothers used cannabis during pregnancy showed no signs of stunted cognitive development at age two.
Researchers examined a cohort of 1,489 mother and child pairs to identify how mothers use cannabis during pregnancy and to investigate prenatal cannabis use impacts the cognitive, motor and language development of their children. The study also aimed to understand if one gender is affected more than the other.
From the original cohort, only 2.6% told researchers that they did use cannabis whilst pregnant, and most of those reported that they stopped by the end of the first term.
“We found that cannabis use during pregnancy was not significantly associated with cognitive, fine motor, gross motor and language development of 2-year-old children,” the study’s authors wrote.
However, researchers cautioned that developmental difficulties might emerge later in childhood. “This [null finding] might suggest that associations of low magnitudes are more likely to appear at developmental stages when higher developmental functions emerge,” they noted.
The study also identified that mothers who used cannabis during pregnancy were more likely to have lower socioeconomic status, use tobacco and alcohol, and experience higher levels of distress in early pregnancy.
Previous research on cannabis use during pregnancy has yielded mixed results. Some studies claim to have found evidence linking prenatal cannabis use to lower birth weights and higher instances of ‘adverse neo-natal outcomes’, with others finding clear benefits for the relief of symptoms such as morning sickness.
The study authors called for more studies to be performed to build on the evidence already collected before being able to make firm conclusions. A study from 2021 which investigated the reasons behind cannabis use during pregnancy and while breastfeeding found that mothers did so to relieve symptoms of pregnancy, as well as for enjoyment and relaxation, and that those who ceased during pregnancy mainly did so out of the fear they would harm their baby.
“Of the 52 pregnant and lactating people interviewed in this qualitative study, those who chose to use cannabis during pregnancy did so mainly to manage symptoms of pregnancy and pre-existing conditions. During lactation, participants used cannabis for reasons that resembled their prepregnancy use, including for enjoyment and relaxation. A small number of participants ceased lactation to resume cannabis use. Most participants who ceased using cannabis during pregnancy or lactation did so because they were worried about the risk of harm to their fetus or infant. Recognizing that many pregnant and lactating people endorse cannabis for symptom management may provide opportunities for clinicians to discuss alternatives that have been proven safe for this population,” the 2021 study concluded.
