Pregnancy

Large-scale, longitudinal studies of humans whose mothers smoked marijuana once or more per week and experimental work on rodents exposed to cannabinoids in utero have yielded remarkably consistent intellectual and behavioral correlates of fetal exposure to this drug. Some exposed individuals exhibit deficits in memory, cognition, and measures of sociability. These aberrations appear during infancy and persist through adulthood and are tied to changes in the expression of multiple gene families, as well as more global measures of brain responsiveness and plasticity. Researchers currently consider these perturbations to be mediated by changes to the endocannabinoid system caused by the active compounds in cannabis. 

The importance of the published findings and the emerging research regarding the potential negative effects of marijuana on brain development are a cause for concern despite the limited research and are the basis for the following recommendations:

1. Women who are considering becoming pregnant or who are of reproductive age need to be informed about the lack of definitive research and counseled about the current concerns regarding potential adverse effects of THC use on the woman and on fetal, infant, and child development. Marijuana can be included as part of a discussion about the use of tobacco, alcohol, and other drugs and medications during pregnancy.
2. As part of routine anticipatory guidance and in addition to contraception counseling, it is important to advise all adolescents and young women that if they become pregnant, marijuana should not be used during pregnancy.
3. Pregnant women who are using marijuana or other cannabinoid-containing products to treat a medical condition or to treat nausea and vomiting during pregnancy should be counseled about the lack of safety data and the possible adverse effects of THC in these products on the developing fetus and referred to their health care provider for alternative treatments that have better pregnancy-specific safety data.
4. Women of reproductive age who are pregnant or planning to become pregnant and are identified through universal screening as using marijuana should be counseled and, as clinically indicated, receive brief intervention and be referred to treatment.
5. Although marijuana is legal in some states, pregnant women who use marijuana can be subject to child welfare investigations if they have a positive marijuana screen result. Health care providers should emphasize that the purpose of screening is to allow treatment of the woman’s substance use, not to punish or prosecute her.
6. Present data are insufficient to assess the effects of exposure of infants to maternal marijuana use during breastfeeding. As a result, maternal marijuana use while breastfeeding is discouraged. Because the potential risks of infant exposure to marijuana metabolites are unknown, women should be informed of the potential risk of exposure during lactation and encouraged to abstain from using any marijuana products while breastfeeding.
7. Pregnant or breastfeeding women should be cautioned about infant exposure to smoke from marijuana in the environment, given emerging data on the effects of passive marijuana smoke.
8. Women who have become abstinent from previous marijuana use should be encouraged to remain abstinent while pregnant and breastfeeding.
9. Further research regarding the use of and effects of marijuana during pregnancy and breastfeeding is needed.
10. Pediatricians are urged to work with their state and/or local health departments if legalization of marijuana is being considered or has occurred in their state to help with constructive, nonpunitive policy and education for families.

Researchers had two women conduct "mystery caller" phone conversations with employees at 400 dispensaries across the state, telling them that they were eight weeks pregnant and suffering from morning sickness. During the majority of those calls, the employees recommended the women use cannabis products.

1. Legalizing cannabis has been shown to increase the rates of motor vehicle accidents.
2. Cannabis use is a risk factor for mental illness.
3. Inhaled Cannabis use is a risk factor for respiratory infections.
4. Cannabis use increases the rate of vascular disease. Cannabis is the third most often identified drug of abuse
5. Cannabis use during pregnancy has been associated with increased risk of adverse birth outcomes
6. Legalization of cannabis has been shown to increase cannabis exposure in the pediatric population.
7. Heavy cannabis use is associated with diminished lifetime achievements.
Doctors must educate the public about the potential harm cannabis causes with heavy, and possibly moderate, widespread use just as they do about the dangers of tobacco use. Tobacco use has declined in the United States in large part because of the knowledge the public now holds about its adverse effects, as opposed to legislative action.

Marijuana use during pregnancy can be harmful to your baby’s health. The chemicals in marijuana (in particular,tetrahydrocannabinol or THC) pass through your systemto your baby and can negatively affect your baby’s development.

Connection between legalization of marijuana and increase opioid addiction.
The effects of marijuana on the brain of an unborn child. Predisposing children for addiction. Here are the studies cited. 

Summary: Cannabis use during pregnancy is associated with abnormal brain structure in children, according to a new study. Compared with unexposed children, those who were prenatally exposed to cannabis had a thicker prefrontal cortex, a region of the brain involved in complex cognition, decision-making, and working memory.

Children whose mothers use marijuana during pregnancy have a higher risk of stunted growth and of developing ADHD, anxiety, and depression later in life.
When THC enters the body, it interferes with endocannabinoid’s actions, competing with it for binding sites on target cells and generally getting its way.

My main finding is that it's primarily women who were younger when they become mothers who do continue to use marijuana overtime. Also women who are depressed over longer periods of time, women who smoke, women who use more than the recommended amount of alcohol are more likely to continue to use marijuana while pregnant as well as when they're raising their children. So the take-home messages is to ask women about marijuana use. We know that marijuana use is considered more and more acceptable by women and that they may continue to use while they are pregnant and while they are having children.

• Prenatal exposure to marijuana has been shown to be predictive of psychotic symptoms in young adulthood.
• Monitoring the Future survey reported a five-year decline in the perceived harm of regularly smoking marijuana, from 52.4% of high school seniors to 36.1%
• Marijuana is the most widely used illegal drug in the United States and it is estimated that it is used by 61% of all persons suffering from a substance use disorder related to drugs other than alcohol.
• The risk of developing addiction associated with cannabis use has been reported to increase to about 17% among those who start using marijuana in adolescence, and to 25-50% among those who smoke marijuana daily.
• Smoke from marijuana combustion has been shown to contain a number of carcinogens and cocarcinogens, as well as many of the toxins, irritants, and carcinogens as tobacco smoke. 
• Marijuana-infused edibles account for 45% of the legal marijuana marketplace.
• AMA Marijuana has a high potential for abuse. It has no scientifically proven, currently accepted medical use for preventing or treating any disease process in the United States.

Number Using Opioids and Marijuana on the Rise

Chart: Colorado among states with growing heroin, prescription drug abuse problem 

Consistent with the past, in 2014 still only 47 percent of operators involved in traffic deaths were tested for drug impairment.

Studies show that children exposed to marijuana in utero have lower scores on tests of visual problem-solving, visual and motor coordination, and visual analysis, compared with children not exposed to the drug, the report states. Prenatal marijuana exposure also has been associated with decreased attention span and behavioral problems. The nervous system of a human fetus can respond to the chemicals in marijuana within 14 weeks of gestation, and studies have shown that 14-year-olds are more likely to be marijuana users if their mothers used the drug during pregnancy.

State of the Science   190 resources
Several problems are associated with marijuana use during pregnancy, because prenatal exposure influences brain development and can result in permanent cognitive impairment. [35] Cognitive deficits resulting from prenatal exposure include inattention; impulsivity; and impairment in learning, memory, and certain aspects of executive functioning. [36] In addition, prenatal exposure to cannabis has been associated with reduction of fetal growth. [37]
For many years, the myth of smoked cannabis being "healthier" or "no worse" than smoked tobacco was perpetuated by pro­marijuana groups. Both smoked cannabis and tobacco contain approximately 4000 chemicals and that these chemicals are essentially identical in both plants.In another recent review, [23] the authors concluded that "smoking of cannabis is not medically recommended due to the potential respiratory tract, dangers of noxious compounds such as polycyclic aromatic hydrocarbons, tar and carbon monoxide."
 
 

Appendix

Changes in Marijuana Use Patterns, Systematic Literature Review, and Possible Marijuana-Related Health Effects

Recent attention has been focused on the long-term impact of cannabis exposure, for which experimental animal studies have validated causal relationships between neurobiological and behavioral alterations during the individual's lifetime.

Cannabis has enormous affinity for milk and produces a milk/plasma ratio of 8, although the levels in milk are generally considered subclinical. THC crosses the placenta readily, and there is increasing evidence that it may increase rates of growth retardation and adverse neurodevelopment following prenatal exposure.
 
One study indicated an increased incidence of reduced head circumference in young adolescents (9-12 years of age) who were exposed in utero to heavy marijuana use.  Prenatal exposure resulted in a higher rate of low birth weight infants and childhood leukemia. Recent studies have suggested a reduction in long and short-term memory retrieval and retention in children exposed to prenatal cannabis. These children were also weak in planning, integration, and judgment skills.
 
While the effect of cannabis on infants from breastfeeding mothers is limited, cannabis use in breastfeeding mothers should be strongly discouraged. Thus, in pregnant and breastfeeding mothers, this drug should no longer be viewed as safe.