Marijuana During Pregnancy: Is It Safe?

Daily marijuana use during pregnancy can have significant effects on fetal health, including low birth weight and low resistance to infection, according to the authors of a recent study.

Although previous research has linked marijuana use with adverse fetal neurodevelopmental outcomes, the number of women using marijuana during pregnancy has increased following its legalization, according to the researchers.

They conducted a retrospective cohort study using data from pregnant women who self-reported daily marijuana use and controls. Maternal demographics, fetal biometry, nuchal translucency, and umbilical artery Dopplers were compared between the two groups.

In first and second trimester ultrasounds, no differences were noted between marijuana uses and controls. However, second trimester umbilical artery systolic to diastolic ratios were higher in the marijuana users compared with controls (4.02 versus 3.92). In the third trimester, growth restriction was noted in 26 of the 192 marijuana exposed fetuses compared with 6 of 192 controls. Among the marijuana users, 4 cases of absent and reversed end diastolic flow were observed. None were observed among controls.

“Our data shows that daily marijuana use is associated with impaired fetal growth and increased placental vascular resistance. Marijuana consumption in pregnancy should be avoided until further studies delineate its exact potential for fetotoxicity,” the researchers concluded.

—Michael Potts

Reference:

Brar BK, Patil JS, Jackson DN, et al. Effect of intrauterine marijuana exposure on fetal growth patterns and placental vascular resistance [published online November 11, 2019]. J Matern Fetal Neonatal Med . https://doi.org/10.1080/14767058.2019.1683541.