High Stakes: The Science and Stigma of Cannabis and Motherhood

Traditional anti-nausea medications do not always work, and some carry their own risks or intolerable side effects. Faced with limited options, some pregnant people turn to cannabis, especially if they already have personal experience with the plant.

Emily Kyle of Rochester, New York, has two children and used marijuana during her second pregnancy. She was diagnosed with hyperemesis gravidarum by her OB-GYN when she was dealing with constant, intense nausea and was unable to keep food down.

Her doctor recommended traditional medications, but when Kyle said she preferred to use her vape pen once or twice a day, her doctor was supportive. She continued to use her vape pen to manage nausea and vomiting through the 17th week. Her son was born weighing about six and a half pounds and has hit every developmental milestone. Currently, he attends preschool, where he has learned to write his name and has no behavioral concerns.

Anxiety is another major reason to use cannabis during pregnancy. For people with preexisting anxiety disorders or those who have relied on cannabis therapeutically before pregnancy, the decision to continue using it can feel like a matter of stability rather than indulgence.

Many have incorporated cannabis into a standard wellness routine long before conceiving, using the plant to manage stress, pain, or sleeplessness. For them, stopping abruptly can feel both physically and emotionally destabilizing, especially when alternative treatments are limited or less effective. Prescription anti-anxiety drugs may be discouraged during pregnancy, leaving cannabis as a familiar alternative.

In many cases, these decisions are made in the absence of clear medical guidance. Because federal restrictions have limited independent research on cannabis and pregnancy, pregnant people are left to weigh anecdotal evidence against an incomplete scientific record. They must navigate conflicting advice from doctors, family members, and online forums, often in secrecy to avoid stigma or judgment. For some, using cannabis becomes a pragmatic choice and a way to preserve their physical and mental well-being when the medical system offers few compassionate solutions.

What Data Do We Have On Cannabis & Pregnancy?

The general medical consensus is that cannabis use during pregnancy increases the chances of preterm birth and low birth weight. Any infant that weighs less than five and a half pounds at birth is considered to have a low birth weight. Infants tend to lose a little bit of weight shortly after birth, so the expectation here is that fatter babies have a better chance of survival.

Similarly, infants born before completion of the 37th gestational week are considered to be premature. The earlier a baby is born, the higher the risk of complications, especially because the lungs and brain are some of the last organs to fully develop.

A study published in 2019 from Ontario that analyzed 661,617 pregnancies found that self-reported cannabis use in pregnancy was associated with a higher risk of preterm birth even after adjustment for confounding variables. A systematic literature review from 2024 found that prenatal cannabis use increased the odds of low birth weight, preterm birth, and fetuses that were small for their gestational age. Many other studies have consistent data.

However, there is no data on how different formulations of cannabis (e.g. smoking versus vaping versus edibles) affect a fetus, and we have no data comparing the effects of CBD versus THC.

The most prominent study that contradicts the medical consensus was conducted in 1988 in rural Jamaica. The study, titled “Newborn Outcomes with Maternal Marihuana Use in Jamaican Women,” by Janice Hayes, Melanie Dreher, and J. Kevin Nugent, examined whether maternal cannabis use during pregnancy affected infant health and development.

It followed 30 cannabis-using women and 26 non-users through pregnancy and the first month postpartum. Researchers collected data on marijuana use patterns, birth outcomes, and neonatal behavior using the Brazelton Neonatal Behavioral Assessment Scale (BNBAS), which measures neurological and social responsiveness in newborns.

The results showed no significant differences in gestational age, birth weight, or length between infants of cannabis users and non-users. By one month, however, babies born to cannabis-using mothers scored slightly higher on measures of autonomic stability and state organization, meaning they were more alert, better able to regulate sleep-wake cycles, and less prone to stress reactions. The authors attributed these differences not to direct effects of cannabis exposure but to environmental and cultural factors.

In Jamaican households where marijuana use was common, mothers tended to have stronger social networks, more economic independence, and greater access to food and resources. These supportive caregiving environments appeared to offset any potential negative effects of prenatal cannabis exposure.

While positive on its face, these results are limited. The sample size is very small; the study followed only 30 women using cannabis. It would be inadvisable to extrapolate the results from this study to other, larger populations. Second, while we don’t have any sort of testing data from the marijuana consumed during the study, we can assume that it didn’t have the ultra-high THC content commonly found today. It’s possible that the marijuana consumed would have resembled today’s hemp, with a significantly lower THC concentration. If true, this would mean that we have even less data on the effects of marijuana on fetal development than we suspect.

Lastly, even the authors of the study pointed out that the women who consumed cannabis had better social networks and stronger access to food and healthcare. They were already doing very well in life, so it could be expected that their children would also do well, whether or not cannabis was in the picture.

Why is Studying Cannabis and Pregnancy So Complicated?

In the United States, any medical study involving human participants must first be approved by an Institutional Review Board (IRB). These committees review study designs to make sure participants are informed of risks, that benefits outweigh potential harm, and that privacy is protected. IRBs serve as the ethical gatekeepers of research, ensuring safety and maintaining public trust in science.

Because marijuana is still classified as a Schedule I drug, meaning the federal government claims it has no accepted medical use, researchers face additional hurdles. Any study involving marijuana requires approval from not just an IRB but also the Drug Enforcement Administration, the Food and Drug Administration, and the National Institute on Drug Abuse. If any one of these agencies withholds or delays approval, the research cannot move forward. These bureaucratic barriers often discourage scientists who might otherwise pursue marijuana-related studies.

Recent reporting in The New York Times revealed another complication: many ethics boards are now owned or influenced by the same corporations whose trials they review. Once designed to safeguard participants, IRBs have become increasingly commercialized, creating potential conflicts of interest.