The Inexact Science of Cannabis and Pregnancy

The Inexact Science of Cannabis and Pregnancy

While little scientific research exists about cannabis' effects on pregnancy, breastfeeding, and babies, one thing is certain: more and more mothers are using it. Why?

There is plenty of conjecture about cannabis use during pregnancy but very little fact. Despite women using cannabis for millennia during menstruation, pregnancy, childbirth, and breastfeeding, doctors and government officials have become increasingly wary of the topic. Some cite flawed studies to prove it is dangerous to the development and growth of offspring, but from a truly scientific point of view, medical professionals have very little knowledge on how cannabis use during this critical time affects real human babies. Either way, more and more women are doing it.

One doctor has at least set out to understand what can be gleaned from the studies and to highlight the flaws in research available to medical professionals on the topic. Dr. Laura Borgelt, PharmD, FCCP, BCFS recently presented her findings at the third Marijuana for Medical Professionals conference in Denver, which provides continuing medical education credits to doctors nationwide. Borgelt also surveyed how dispensaries responded to calls from pregnant mothers and found major flaws in both the response from the research and medical community as well as the cannabis industry.

She says she decided to embark on these studies with the University of Denver because she identified the major gap between medical knowledge and patient practice. One day during a consultation with a pregnant mother and medical resident she says the question of whether it was safe to consume cannabis during pregnancy and breastfeeding clearly highlighted the need for the work.

The resident told the patient that was completely fine. I sat there in my chair thinking to myself, ‘I am pretty sure that is wrong, but I don’t know if it is right,’” Borgelt said.

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She points out that while the information on pregnancy and child development is light and inconclusive, there is even less research to work from on breastfeeding and lactation. She also notes a major flaw in the research; almost all of it refers specifically to the cannabinoid THC, leaving yet another gap in the study on CBD, other cannabinoids, and whole plant cannabis. As in most knowledge gaps in cannabis, there is also a large gap between medical research and the practice of how humans actually interact with cannabis and its chemical constituents.

Although Dr. Borgelt’s research has left more questions opened than answered, she says for now the safest option is to avoid cannabis use in pregnancy and breastfeeding.

Medical cannabis has this benefit and risk that needs to be considered at all times in every patient, no matter how and when they are using it,” Borgelt said.

Despite what the medical profession has to say on the topic, 15 to 28 percent of pregnant and breastfeeding mothers in and out of legal states are using cannabis. With so much uncertainty, why are they risking it?

The Information Gap

In Borgelt’s literary review, she sorted through hundreds of studies on pregnancy and breastfeeding with the goal of determining if there is an effect on fetal development due to cannabis use.

This migration, development and formation (of a human fetus) is astonishingly complex,” she said. “We know the endocannabinoid system is critical in development and neuroprotection.”

She notes that there are higher numbers of CB1 receptors in the fetal brain than the adult brain. CB1 receptors are receptors in the nervous system that interact with cannabis and endogenous cannabinoids produced by the human body. The higher presence of receptors means the effects of cannabinoids would be more potent on a developing fetus or child than an adult. Borgelt says there is a potential that because THC could disrupt and interfere with proper cell signaling during the development of these neurotransmitter systems there could be an effect on fetal development. However, there is still no definitive current research that could prove or disprove this.

As far as birth defects – the results of fetal development having been disrupted – there isn’t substantial evidence of this either. Borgelt says this speaks to the types of trials conducted and their limitations and points out that a lack of conclusive evidence is positive.

It is good news to me that this is not a thalidomide tragedy,” Borgelt says.

But she says the literature does point, but not prove, to the possibility that cannabis could affect mental development, which would not become apparent until adolescent and teenage years, noting the human brain does not stop developing until the age of 25. Again, however, the studies don’t sufficiently confirm the theory.

We have found there is no substantial evidence, but there is moderate evidence, for attention problems, decreased IQ scores in young children, decreased cognition and growth,” Borgelt said.

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But as Dr. Rachel Knox pointed out during a question and answer session with Borgelt at Marijuana for Medical Professionals, none of the research available accounts for other “confounding factors” or potential causes or contributors to the measured condition. All of the potential problems Borgelt mentioned could be attributed to other known causes such as socioeconomic status, other mental health problems, nutrition and access to healthcare and/or education.

We see those confounders as very closely related to all the possible problems you are listing in the teen years. I bring it up because populations who use it [in pregnancy and breastfeeding] are usually from a lower socioeconomic status,” Dr. Knox said.

Dr. Borgelt agreed with Dr. Knox and added that these studies were flawed because they didn’t account for these other confounding factors.

As for the effects of cannabis use during breastfeeding, Dr. Borgelt acknowledges even less is known with the available studies.

Human breastmilk contains endogenous (produced within the body) cannabinoids, which can account for the sleepy “high” babies get after a meal. While these natural cannabinoids in breastmilk are safe, Dr. Borgelt warns that very little is known about phytocannabinoids in breast milk.

We have no information, or very, very little information. What we can say is THC readily passes into the breastmilk and there are numerous studies to confirm that. Chronic users will have up to eight times more THC in the breastmilk than in the plasma,” she said. “It is about the potency and the impact being higher and longer. When I have patients that ask about that, I will fully acknowledge our body makes its own endocannabinoids, but the exogenous are far more potent and last longer on receptor sites than what our body does normally which can influence the way the cell functions and develops.

Why Women Use Cannabis During Pregnancy and Breastfeeding

It is hard to convince a mom (not to use cannabis) when she is puking six times a day,” says Borgelt.

One of the primary reasons women use cannabis in pregnancy is for immediate relief of nausea. Women who are more comfortable with medical use of cannabis are more likely to view cannabis use as safer than pharmaceutical drugs that could be prescribed to women in pregnancy.

There is a historical precedent for cannabis use in pregnancy. Cannabis has been used by midwives and herbalists to treat pain during menstruation and child birth and pain, nausea, anxiety, and insomnia in pregnant women for millennia. American and English doctors as late as the 19th century would recommend cannabis to mothers to induce and hasten childbirth. Although there are thousands of years of human experience with cannabis use during reproduction, very little formal study can point to any absolutes about effects.

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In the 1990s, Dr. Melanie Dreher, currently the Dean of the Rush University Medical Center in Chicago and previously the Dean of Nursing at the University of Iowa College of Nursing, conducted a series of studies that are considered the most thorough studies of cannabis use in pregnant and breastfeeding mothers. She followed mothers in rural Jamaica already regularly using real cannabis during pregnancy and breastfeeding, and the development of their children over time.

She found in 1994, “the (cannabis) exposed neonates showed better physiological stability and required less examiner facilitation to reach organized states. The neonates of heavy-marijuana-using mothers had better scores on autonomic stability, quality of alertness, irritability, and self-regulation and were judged to be more rewarding for caregivers.”

One thing is certain, women have and will continue to use cannabis during pregnancy and breastfeeding. Real longitudinal studies that account for a host of confounding factors like other substance use, nutrition, genetic conditions, wellness and socioeconomic status are necessary to prove if there are negative side effects to development or growth of human offspring. Right now, those studies don’t really exist and no definitive statements can be made.

While Borgelt encourages doctors to err on the side of caution, she acknowledges these flaws in research and suggests doctors keep an open mind so that doctors can get honest dialogue with their patients.

I want to encourage you to continue to have the conversations with these women,” she said.