As the social acceptance of
cannabis for recreational and medicinal uses increases, physicians and
childbearing women need to understand the potential short-term or long-term effects of using the drug
That’s what Julie A. Kmiec, DO, assistant professor of psychiatry at the University of Pittsburgh, aims
to do in the session “Impact of Medical and Recreational Marijuana on Women and Children” on Monday at
10 a.m. in Ballroom B, Level 300, Convention Center. The hour-long session is part of the American
College of Osteopathic Obstetricians and Gynecologists (ACOOG) and the American Osteopathic Academy of
Addiction Medicine (AOAAM) joint program.
“Although it is commonly thought of as a harmless substance and deemed a ‘medicine,’ by legislative
bodies, cannabis is not recommended for use during pregnancy,” Dr. Kmiec said. “Patients should be
educated that effects may not be visible at birth or detected until their child is older.”
Cannabis is the most common illicit drug used in pregnancy—about 2 to 5 percent of women use it while
pregnant (based on epidemiologic, retrospective and prospective studies)—and some sources indicate its
potency has increased from 3 percent in the 1960s to about 12 percent in 2014, Dr. Kmiec said. While it
is unknown how this change in potency will affect fetal development, studies done when the potency of
cannabis was lower found some neuropsychological differences in children who had prenatal exposure to
cannabis compared to those with no exposure. These differences include impulsivity, hyperactivity and
Dr. Kmiec will discuss the results of three prospective longitudinal studies of prenatal cannabis
exposure that have been done with follow-up studies of their children.
Studying cannabis’ effects during pregnancy can be challenging due to the retrospective nature of many of
the studies. They often rely on recall of the participants, which may be erroneous, and may also be
subject to social desirability bias, Dr. Kmiec added.
“There are also confounding factors that affect prenatal development which make cannabis use difficult to
study in isolation, such as tobacco, alcohol, and other substance use, poorer nutrition, lower
socioeconomic status, and lack of folic acid supplementation,” she said.
A retrospective study published by Chabarria et al. from Baylor in 2016 was consistent with past studies,
finding that cannabis use alone was not associated with adverse fetal outcomes. However, use of cannabis
plus tobacco was associated with preterm birth and decreased neonatal head circumference and birth
weight, with an increased adjusted odds ratio above that of tobacco use alone, suggesting an additive
effective of cannabis with tobacco.
Dr. Kmiec will discuss these results during the session in addition to addressing welfare policies that
affect pregnant women who use substances and informing physicians on the benefits/risks of breastfeeding
in post-partum women who use cannabis.
“Patients should be educated that effects may not be visible at birth or detected until their child is
older,” she said.