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Stirring the Pot: Pregnancy & Pot

Dr. Melanie Bone

By Dr. Melanie Bone

April 26, 2022

With Mother’s Day right around the corner, it is a good time to explore the topic of

At the moment, the party line from organizations such as the American Medical Association and the American College of Obstetricians and Gynecologists (

) states that cannabis use – CBD, THC or both – is verboten for women trying to get pregnant, who are already pregnant, or who are in the postpartum period while breastfeeding. The same goes for alcohol and other substances. 

It is easy to see why this prohibition stance is the norm, as there are almost no reliable scientific studies about the impact of cannabis on eggs in the ovaries that are destined to become fetuses, on the developing child and on the breastfeeding newborn. 

Looking Closer at Past Studies


cited in the literature that inform this approach to cannabis and pregnancy point to numerous negative outcomes associated with the use of cannabis in the perinatal period. These include low birth weight less than six pounds, increase preterm birth, increase risk of admission to a neonatal intensive care nursery and possible behavioral and developmental delays in the children of moms who are cannabis users. They cite a lower IQ in children exposed to cannabis in the womb of about five points. 

A deep dive into these studies shows that they did not control for many factors. For example, one of the most frequently cited studies included women who smoked cigarettes as well as cannabis. Smoking, in general, has been shown to have a deleterious effect on pregnancy. There are no head-to-head comparisons of women who only smoke cannabis while pregnant with women who only smoke cigarettes while pregnant, or with women who smoke both. This makes interpretation of the data more difficult. 

Also, studies lump the method of cannabis ingestion together. It is inaccurate to compare outcomes of women who use edibles while pregnant with women who use smoking or vaping while pregnant. Studies that are based on questionnaires are highly subject to recall bias, meaning that the women answering the questions may not recall accurately or omit things about their substance use. This is a major problem for these studies. 

Cannabis Use During Pregnancy

There are a few women’s groups known for promoting use of cannabis before, during and after pregnancy. They assert many reasons why they do so. For example, some women trying to conceive are anxious and use cannabis to relax them. They perceive that it helps them to get pregnant and worry less about the impact on their fetus, because many will stop as soon as they become pregnant. Others start to use while pregnant, primarily because of morning sickness. 

Cannabis is known to help manage nausea and vomiting, and has been touted as a great way to treat

, a condition so severe that women often need hospitalization with intravenous fluids and nutrition while pregnant. Their contention is that the cannabis is more natural and if it helps to prevent invasive interventions during pregnancy, then it is a positive alternative to allopathic regimens.

An interesting phenomenon is that women will often stop smoking cigarettes and drinking alcohol while pregnant because they are prioritizing the health of their fetus. While many cannabis users will do the same, there are a fairly large group of women who feel that cannabis is safer than tobacco and alcohol, and they continue to use. The proponents of this group  point to cultures where cannabis use is generally well accepted and argue that the children born into those cultures (Rastafarians, for example) do not appear to be any different from children without exposure to cannabis while in the uterus.

Women who have delivered have been described as being in the “fourth trimester” of pregnancy. For those who are breastfeeding, there is ample evidence that cannabinoids from the mother pass into breast milk as they cross the placenta to the developing fetus. Remnants of THC have been found in breast milk up to 6 weeks after use by the mother.

At the end of the day, we need more studies to prove what exactly cannabis may or may not do to a baby. Until that happens, it is common sense to reject it as possibly unsafe. And because we live in a free society, there will always be women who choose, as a matter of their personal right, to use cannabis while pregnant. 

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Understanding Cannabis Use and Pregnancy

The scary part is that this use is perceived as a form of

in some states. Women with positive urine screens for cannabinoids during pregnancy are subject to investigation by their state. They can possibly lose custody of their child, go to jail, or both. Because of this risk, most women will hide their cannabis use when pregnant. Urine drug screens are not done on every woman who is in labor, so they are betting on never being caught. 

Every day women ask me how to navigate this path. They use cannabis regularly and feel it is their right to do so, even while pregnant. They do not feel it is the right of the government to interfere with their privacy.

If we really knew to what extent, if at all, that cannabis is detrimental during pregnancy, then the correct approach would be obvious. If they discover that cannabis does lower IQ and birth weight, the question remains as to whether this is enough of a disincentive for women who use. If these women choose to continue knowing the impact, then is that a crime? 

Right now, smoking tobacco while pregnant has been

to lower birth weight and increase the risk for pregnancy-related complications. But it is not illegal to smoke while pregnant, just frowned upon. Should cannabis be treated the same? With a warning? Would it be different if cannabis were federally-legal? We might possibly prove that it is about as dangerous as cigarettes, but would it be a reportable offense? Certainly you do not lose the right to have your baby if you smoke cigarettes and expose your infant to second and third hand smoke.

There is also the question of who uses cannabis and why. Is a white, upper-middle class mom-to-be who has excellent nutrition, good support systems, and solid medical care while pregnant, presenting her fetus with the same risk of using dispensary-purchased cannabis for her anxiety as a Black or Brown, inner-city woman who uses federal-assistance for food and housing, has less prenatal care, and uses street cannabis as a way to self-manage mental health issues? The socioeconomic situations greatly impact maternal and fetal well being, and these really have not been scrutinized carefully enough to know how much they contribute to the outcomes of cannabis use in pregnancy. 

My hope is that we will see more and more interdisciplinary studies being undertaken to assess the impact of cannabis on pregnancy. Only then can we make cogent recommendations about this delicate subject.

I close with mentioning

published in Frontiers in Psychology by members of the School of Social Work and Department of Psychology at Columbia University as well as colleagues, which provided a critical review of the literature on cannabis during pregnancy and the risk for cognitive impairment in the fetus. They concluded that cannabis exposure in utero was not associated with “clinically-significant cognitive functioning impairments” in the babies.

Until we have better resolution of these issues, it is the safest bet not to use cannabis if you are going to have a baby or if you are breastfeeding. It’s not forever, and if your child has any type of impairment, you can be relieved to know that it has nothing to do with any substance you might have exposed them to in utero. Otherwise, guilt may be lifelong.

Happy Mother’s Day!

Dr. Melanie Bone

About The Author

Dr. Melanie Bone