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Cannabis and Pregnancy

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Cannabis is the most frequently used illicit/ illegal drug in Western countries, and becoming increasingly legalized and accessible. There is a growing amount of research and studies being done, and most show that marijuana use may be associated with fetal growth restriction, preterm birth, and stillbirth. With the legalization in Oregon and Washington this issue has an increasing effect on chiropractic practice in our state, and our patients as a whole.

There are dozens of documented papers on the neuronal effects of THC in adult users, but less is known about the use during pregnancy. Pregnancy in this paper is not looking just at the term of a mother carrying child, but also fertility (male and female), implantation, parity, delivery and then breastfeeding. The long term effects of marijuana use are currently being studied at great lengths and interesting results are being found, but those will largely be excluded from the scope of this paper.

“There is an emerging body of evidence indicating that marijuana may cause problems with neurological development resulting in hyperactivity, poor cognitive function, and changes in dopaminergic receptors. In addition, contemporary marijuana products have higher quantities of delta-9-tetrahydrocannabinol (THC) than in the 1980s when much of the marijuana research was completed. The effects on the pregnancy and fetus may therefore be different than those previously seen. Further research is needed to provide evidence-based counseling of women regarding the anticipated outcomes of marijuana use in pregnancy. In the meantime women should be advised not to use marijuana in pregnancy or while lactating.” (Metz et al)

Marijuana has long been reported to affect the fertile ability of both male and females (negatively). The cannabinoid introduced from an external source (marijuana) is similar (but I have not seen exactly how) to the natural endocannabinoids which we have in our system. In addition to estrogen interactions, endocannabinoid activity has been shown
to attenuate progesterone release from the corpus luteum. This has made for a long standing discussion/ argument on the role of cannabis use on implantation. There are a variety of viewpoints on this, which I believe is largely due to the human and cannabis versions of endocannabinoids.

“In the past few decades, a large amount of evidence has demonstrated that endocannabinoid signaling via cannabinoid receptors is an important player in various female reproductive events, including sperm-egg fusion as fertilization, preimplantation development of embryos and their timely transport from the oviduct into the uterus, attainment of uterine receptivity, embryo-uterine crosstalk during implantation and decidualization, trophoblast differentiation and placental development, and initiation of parturition.” (R. Meccariello et al)

Although there are myriad different papers and research on the different potential problems with marijuana use in pregnancy and breastfeeding, there is limited data due to the advent of recent legalization, and therefore a lack of significant research. A good deal of work has been done and is continuing to be elucidated at present.Pre-eclampsia, need for incubator at birth, use of forceps, parental history of psychosis, and low birth weight were associated with an earlier onset of psychosis. Stimulant drugs, which were mostly used together with cannabis, were also associated with an earlier onset of psychiatric/ neurologic disorders. (Rubio-Abadal Et al)

Current evidence indicates that cannabis use both during pregnancy and lactation, may adversely affect neurodevelopment, especially during periods of critical brain growth both in the developing fetal brain and during adolescent maturation, with impacts on neuropsychiatric, behavioral and executive functioning. These reported effects may influence future adult productivity and have significant lifetime outcomes.

During fetal development the CB1 receptors facilitate the migration of neurons into the babies brain. Replacing the natural chemicals with cannabis can have detrimental effects on the perinatal neuronal development. So, ingesting THC at this time frame of a fetuses development can result in signaling cascades that disrupt fetal cortical circuitry specification.
The endocannabinoid system in the human body is most largely made up of two G- protein coupled receptors for cannabinoids (CB1 and CB2). CB1 receptors are found in neural, reproductive and endocrine tissue. CB2 receptors are mostly found in immune tissue. Introduce cannabis to this system and there is an outside influence on this internal signaling system, and the aforementioned systems are altered. With the alteration of these processes deviation from the normal is more often present. Marijuana use before onset of psychosis can act as a precipitant of psychosis. “Cannabis has been the drug most closely related to earlier onset of learning disabilities and mental diseases.” (Rubio et al)

Other research shows that bradycardia and hypotension occur with larger doses of marijuana, while smaller doses present with tachycardia. If a patient is about to deliver with other drugs (anesthetics) involved, then the possibilities of complications could ensue. Think of a mom about to have her first baby -high- and stressed if her heart rate is elevated and esophagus potentially inflamed (from smoking), then anything the anesthesiologist might use containing epinephrine, ketamine, or pancuronium could have adverse to catastrophic effects. With larger doses the obvious vital consequences are even more catastrophic.

A French paper stated that 1.2% of women reported having used cannabis during pregnancy. This percentage was higher among single, younger women, who were living alone, or women who had a low level of education/income. THC use was also associated with tobacco consumption and drinking alcohol. “Cannabis users had higher rates of spontaneous preterm births: 6.4 versus 2.8%, for an adjusted odds ratio (aOR) of 2.15 (95% CI 1.10–4.18). The corresponding aOR was 2.64 (95% CI 1.12–6.22) among tobacco smokers and 1.22 (95% CI 0.29–5.06) among non-tobacco
smokers.” (M-J Saurel-Cubizolleset al)

“Cannabis users were more frequently tobacco smokers than were non-users, and the highest proportion of women who smoked at least ten cigarettes a day or more was found among those who used cannabis at least once a month. Cannabis users were also consumers of alcohol more often than non-users.” (M-J Saurel-Cubizolleset al)

One paper stated: “The current evidence suggests subtle effects of heavy marijuana use on developmental outcomes of children. However, these effects are not sufficient to warrant concerns above those associated with tobacco use.” (Jaques et al) Unfortunately, this misses the point that consumption of cannabis is harmful to the fetus and childhood development. Major congenital birth defects are not reported to be statistically much higher with THC use however. There were two studies in which data were collected prospectively to assess for an association of marijuana exposure with congenital anomalies. Neither of them demonstrated an association between marijuana use and major congenital anomalies.

There are also several large retrospective cohort studies examining whether there is an association between THC use and birth defects, with mixed results. (Metz) The majority of these studies are based on birth defects registries with incomplete understanding of confounding factors and data collected long after delivery, which opens up a can of worms over the accuracy of such studies.

All of this is confounded by the ethical implications of doing human studies on substances that are known to have a negative impact on the human body. This fact alone makes it almost impossible to conduct accurate research on the topic. Add pregnancy to this scenario, and the ethicality becomes more questionable. When we compare animal studies to what is known about human reaction there do seem to be differences. “Many studies have examined hormone levels following acute marijuana exposure. Studies have shown that chronic female and male cannabis users show normal hormone levels.” (Park et al) This does not seem to be the case in monkey, rat and mouse studies.

It does need to be stated that I have found no evidence of an increased incidence of birth defects due to the use of cannabis. this
With the large scale legalization of marijuana and medical use of marijuana, there may be some appropriate uses, but evidence seems convincing at this point that there could be detrimental implications during pregnancy and breastfeeding. The most conclusive proof I have seen in these papers is in chronic regular/ heavy use. Occasional use is much harder to track and record (and people might not be as likely to report use in some areas). Therefore, with less frequent doses, the results are much more difficult to predict. Regular use of THC, like cigarette smoking and alcohol consumption does have a negative affect on fetal physical and neural development and those consequences continue to manifest throughout life.

REFERENCES:
Pregnancy, Breast-feeding, and Marijuana: A Review Article Obstetrical & Gynecological Survey; Hill, Meg MBBS*; Reed, Kathryn MD October 2013 – Volume 68 – Issue 10 – p 710–718
Smoking and Marijuana Use in Pregnancy; Clinical Obstetrics & Gynecology March 2013 – Volume 56 – Issue 1 – p 107–113 doi: 10.1097/GRF.0b013e318282377d Substance Abuse and Pregnancy Brown, Haywood L. Md; Graves, Cornelia R. Md
Cannabis use during pregnancy in France in 2010 BJOG: An International Journal of Obstetrics & Gynaecology Volume 121, Issue 8, pages 971–977, July 2014 M-J Saurel-Cubizolles*, C Prunet and B Blondel
Adverse Health Effects of Marijuana Use; NEJM; Nora D. Volkow, M.D., Ruben D. Baler, Ph.D., Wilson M. Compton, M.D., and Susan R.B. Weiss, Ph.D. N Engl J Med 2014, June, 5, 2014
Updates in Reproduction Coming from the Endocannabinoid System; International Journal of Endocrinology Volume 2014 (2014), Article
ID 412354, 16 pages Rosaria Meccariello, Natalia Battista, Heather B. Bradshaw, and Haibin Wang
Cannabis, the pregnant woman and her child: weeding out the myths; Journal of Perinatology (2014) 34, 417–424; doi:10.1038/jp.2013.180; published online 23 January 2014 S C Jaques, A Kingsbury, P Henshcke, C Chomchai, S Clews, J Falconer, M E Abdel-Latif, J M Feller, and J L Oei
Marijuana use in pregnancy and lactation: a review of the evidence American Journal of Obstetrics and Gynecology Torri D. Metz, MD, MS, Elaine H. Stickrath, MD 5/25/2015
Fetal cannabinoid receptors and the “dis-joint-ed” brain.EMBO J. 2014 Apr 1;33(7):665-7. doi: 10.1002/embj.201488086. Epub 2014 Mar 14 Luigia Cristino and Vincenzo* Di Marzo
Birth weight and obstetric complications determine age at onset in first episode of psychosis.J Psychiatr Res. 2015 Jun;65:108-14. doi: 10.1016/ j.jpsychires.2015.03.018. Epub 2015 Mar 27.Rubio-Abadal E1, Ochoa S2, Barajas A3, Baños I2, Dolz M4, Sanchez B4, Del Cacho N2, Carlson J2, Huerta-Ramos E2; GENIPE Group,

 

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