The Debate on the Effects of Marijuana Use During Pregnancy

Many of the arguments for and against the legalization or decriminalization of marijuana hinge upon its effects on the human body. And one of the most hotly debated topics concerns the consequences of taking the drug during pregnancy: its effect on fetal development, its role in miscarriage, and the possibility of learning and behavioral problems in children whose mothers used marijuana during pregnancy. Since it is an illegal drug in many countries, prenatal exposure to it has raised quite a lot of concern--both for the mother and the child she is carrying.

Statistics show that marijuana, derived from the Cannabis sativa herb, is the most widely used recreational drug among pregnant women.

A number of studies strongly suggest that marijuana is a teratogen--or something that can hinder the normal growth and development of a fetus. Some researchers believe that the chemicals in marijuana enter the placenta, from which the fetus gets the nutrients it needs to grow. Their studies show that some of marijuana’s components, such as delta-9-tetrahydrocannabinol (THC) and carbon monoxide, can impact various aspects of pregnancy. For instance, research conducted in 2006 by embryologists from Vanderbilt University Medical Centre in Tennessee, shows that women who smoke marijuana are at greater risk for a failed pregnancy because it can upset the chemical balance necessary for the safe passage of the embryo from the fallopian tube down to the uterus. This could result in an ectopic pregnancy or an outright miscarriage.

Some other studies indicate that regular use of marijuana during pregnancy plays a role in fetal development and birth weight.

For example, a prospective study done in 1982 at the Yale University Medical School in Connecticut showed that white women who regularly smoked marijuana were at greater risk for delivering low birth weight infants and having infants that are small for their gestational age. Another study, published in the March-April 2005 issue of the journal Neurotoxicology and Teratology, indicated a positive correlation between maternal marijuana use and reduced fetal body weight and foot length.

Another concern is the potential effect of prenatal marijuana consumption on an infant’s behavioraland cognitive abilities.

Research conducted by Swedish scientists and published in the 15 December 2004 issue of the journal Biological Psychiatry suggests that maternal marijuana use may negatively affect the neural systems within the fetal brain that control emotional behavior, leading to unusual neurological manifestations like high-pitched crying, tremulousness, and atypical reactions to visual stimuli--which can also be seen as withdrawal symptoms. Still other studies, such as a prospective one done in Ottawa, Canada, and published in a 1995 issue of Life Sciences, examined the adverse effect of prenatal marijuana exposure on the attention spans of pre-school children and on older children’s problem-solving, reasoning, and analysis skills, attentiveness, impulsiveness, memory, reading, and language-learning. Case-control studies also suggest that prenatal exposure to marijuana is a cause of pediatric cancer.

Other scientists, however, dispute these findings. They argue that the results of such studies are not conclusive due to methodological flaws, such as the failure to isolate marijuana use from other maternal behaviors like tobacco use and alcohol consumption. Also, research conducted so far has failed to conclusively establish that occasional marijuana use by pregnant women leads to a higher risk of birth defects. In fact, Will It Hurt the Baby author Dr. Richard S. Abram states that using marijuana infrequently during the first trimester of pregnancy isn’t likely to result in congenital abnormalities.

They reported that there were no signs of birth defects

A landmark study conducted in the 1990s by medical anthropologist Melanie Dreher, co-author of the book Women and Cannabis: Medicine, Science, and Sociology, gave the medical world a different insight into the use of marijuana by pregnant women in Jamaica. Dreher found that marijuana was being used in a cultural and medical context, as a way to relieve morning sickness or nausea, prevent depression and fatigue, and improve appetites. Her team observed both the mothers who used marijuana and their infants; they reported that there were no signs of birth defects or of behavioral problems in the marijuana-exposed children either during the month after birth or even several years after.

This is not to say that women should have no compunctions about using marijuana regularly and in large amounts during pregnancy. Rather, as scientists like Dreher argue, the medical community should improve its research methodologies, be more thorough, conduct more cross-cultural studies, and refrain from being so quick to conclude without solid evidence that any amount of marijuana use--no matter how slight--during pregnancy will do lasting harm to both mother and child.