There’s conflicting evidence on the safety of cannabis use during pregnancy. Here is what the research says.
With the larger part of America warming up to medicinal cannabis, people are getting curious about how far they can push their love for the herb. Women are wondering if they should abandon the practice just because they are pregnant, or to take the pregnant belly photoshoot while lighting up. It seems like there’s really nothing wrong about this, but what does the science say?
This article highlights significant studies in this area and the verdict they give about this.
The Jamaica Study by University of Massachusetts
Women in Jamaica have used cannabis for decades, both to treat menstrual cramps and to ease nausea during pregnancy. A study conducted in 1994 by the University of Massachusetts showed positive effects of marijuana use during pregnancy.
These results are quite surprising and contrary to those currently in public domain. Even in states where medicinal marijuana is legal, women are still cautioned against the use of cannabis during pregnancy. Across the border in Canada (cannabis haven), Health Canada strongly maintains that pregnant women should steer clear of cannabis use.
The study was titled “Prenatal marijuana exposure and neonatal outcomes in Jamaica,” and is quoted liberally by pro-cannabis bloggers. It had 40 neonate participants, and 20 exposed to cannabis prenatally while 20 were the control group. All the infants were observed at 3 days and later after they were a month old. The Brazelton Neonatal Assessment Scale was used to score the infants. At three days of age, there was no significant difference in characteristics between the two groups of neonates. However, at 1 month, the exposed neonates showed better outcomes in the following areas:
- Autonomic stability
- Interaction with caregivers
Given that there were no marked differences between the two groups by day three, this could mean that prenatal exposure to cannabis does not cause any harm. The authors concluded that marijuana use during pregnancy is not only safe for the growing child but may lead to better developmental outcomes.
What is the Validity of the Jamaica Study?
This was an ethnographic study, meaning that the participants were observed in their natural environment. Lab or clinical studies tend to pressure participants to “produce right results.” This means that the study participants may act out of pressure to impress the researchers. Ethnographic studies have a greater chance of producing genuine and accurate results.
The Brazelton Neonatal Assessment Scale is a standard test that is ideal for testing the behavior and development of neonates. It is acknowledged on a global standard.
Another Jamaica Study: Older Kids, but Similar Results
Previously in 1991, the Miami Children’s Hospital carried out a “five-year follow-up of rural Jamaican children whose mothers used marijuana during pregnancy.” The children were tested at one day, three days, one month, four years, and finally at five years. The NBAS and McCarthy scales were used to assess development and behavior. At one month, exposed infants had better outcomes in two clusters: autonomic stability and reflexes. At ages 4-5, there were no significant differences between the two groups. Differences observed were linked to the home situation and frequency of attending school.
The Ottawa Prenatal Prospective Study (OPPS)
In 1995, the Carleton University in Canada carried out a study investigating the relationship between prenatal exposure to cannabis and neonatal outcomes. The follow-up study was carried out in 1978 and was ongoing in 1995. The neonates were followed up regularly from birth until they got to six years. Age-appropriate global tools were used to assess behavior.
For the neonates, results revealed that exposed neonates had decreased performance in visual responsiveness and this was attributed to in utero exposure to cannabis. Between ages 1-3, there were no marked differences between the two groups. However, at age 6, exposed children showed impairment in neurological behavior and increased behavior problems.
The researchers argued that the lack of difference in performance between ages 1-3 should not rule out the effects of prenatal exposure to marijuana. They went ahead to claim that the negative effects observed later could be linked to marijuana use during pregnancy.
It is not clear why the neurological differences did not feature in early childhood. It could also be that at 6 years, the differences observed in the OPPS were related to the mother’s behaviors and other confounding variables. In Canada, it is reported that cannabis use during pregnancy is much higher among teenage mothers than it is in older women. However, it is better to go with the conclusions arrived at by the researchers in this study.
So, is Cannabis Safe for Pregnant Mothers?
With the conflicting evidence given above, it is difficult to give a clear answer. However, The American college of Obstetrics and Gynecology strongly recommends that pregnant women abstain from cannabis use during pregnancy.
Compounds in cannabis cross the placenta and can affect the development of the growing baby. Because we are not certain of the implications of this, it is better to avoid cannabis use in pregnancy. As much as cannabis therapeutic potential appears promising, it is not yet time to embrace this holistically. Issues such as optimum dosing, adverse effects on the brain and drug interactions are yet to be investigated extensively.
Pregnant mothers have other safe alternatives that they can use to support the growing fetus. Unless under the guidance of an obstetrician, it is advisable to avoid cannabis use in pregnancy, even as we wait for larger studies to confirm any benefits of cannabis use during pregnancy.
- NCBI (1994): Prenatal marijuana exposure and neonatal outcomes in Jamaica: an ethnographic study. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/8121737
- NCBI (1994): Five-year follow-up of rural Jamaican children whose mothers used marijuana during pregnancy. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/1957518
- NCBI (1995): The Ottawa Prenatal Prospective Study (OPPS): methodological issues and findings–it’s easy to throw the baby out with the bathwater. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/7539879
- CBC News (2018): Why some mothers keep using cannabis during pregnancy and breastfeeding. Retrieved from https://www.cbc.ca/news/canada/montreal/why-some-mothers-keep-using-cannabis-during-pregnancy-and-breastfeeding-1.4905985