Six dangers of marijuana or THC use during pregnancy

Erin Slocum, RN, practices at Medical Center of the Rockies and Poudre Valley Hospital as a member of the Women and Family Support Team.-
June 2, 2016
  1. a pregnant woman lays on her back in the grass
    Photo: Getty Images.

    It’s not safe for your baby. There is no known safe dose of THC (tetrahydrocannabinol) for pregnant women. Whatever amount of THC the mother takes, a concentrated, higher dose goes to the baby. There will probably never be a known safe dose because the only way to test it would require intentionally giving pregnant women defined doses of a substance known to cause harm to developing brains. To do so would be unethical. So, what happens to embryos and fetuses that are exposed to marijuana in utero? Depending on factors such as age of gestation at exposure, the baby is at an increased risk for significant defects like anencephaly (missing all or part of the brain), lowered IQ or impaired emotional intelligence. Anencephaly is associated with use early in pregnancy and is usually fatal. Lower IQ and emotional intelligence are associated with use later in pregnancy and translate to more developmental delays and a more difficult time making friends. No mother wants that for her kids.

  2. It causes babies to be sedated and have trouble eating. This is most apparent after birth. The toxins from the mother’s THC use are still in the baby’s system, putting them at risk for dehydration and malnutrition.
    THC use causes babies to have withdrawals. This occurs after the toxins have cleared the baby’s system. Symptoms include irritability and difficulty sleeping. Some patients believe that using marijuana during pregnancy leads to an easy-going and good-natured baby; however, this couldn’t be further from the truth. Having a newborn baby can be a difficult transition even under ideal conditions. Marijuana withdrawals only make infancy more challenging.
    It is not safe to use marijuana while breastfeeding. The concentration of THC in breastmilk is eight times of the amount in the mother’s bloodstream. Also, because the body holds onto THC longer than most drugs, it is still present in the breastmilk for up to 30 days after the last time the mother used. In the last several years, our community has made great strides in educating mothers about the benefits of breastfeeding, and most mothers plan to give their child this wonderful gift. Nothing is more heartbreaking than telling a mother she cannot breastfeed her baby because she has been using marijuana. Theoretically, a mother could “pump and dump” her milk for the first month and feed the baby formula instead, letting her body rid itself of the toxins from marijuana. However, the establishment of breastfeeding after a month of formula feeding is not likely to be successful.
  3. It can make nausea and vomiting worse. This can happen from a rare but debilitating reaction to high doses of THC or if a mother who uses large amounts of THC stops using it abruptly. Not only is this documented in scientific research, but local hospitals are admitting an increasing number of patients who are severely dehydrated from vomiting uncontrollably after using high doses of THC. It can take up to 10 to14 days to wean the mother off of tube feedings and IV fluids, while aggressively treating her symptoms around the clock. These symptoms are more severe than those of pregnant women who do not use marijuana.
  4. Synthetic marijuana or “spice” is not safe either. Actually, it can be more dangerous. It can have severe side effects for the mother, such as seizures . Why worry about seizures in pregnant women? Because seizures can cause the placenta to separate from the uterine wall before the mother has delivered the baby. This is called an abruption and can be fatal to both the mother and developing baby, because it causes a massive hemorrhage. Synthetic marijuana can also cause extremely high blood pressure, which puts the mother at risk for an abruption. These devastating effects are in addition to the other risks listed above, and it is worth noting that the concentration of the THC analogues in “spice” are hundreds of times stronger than the original product.
Erin Slocum


We hope this knowledge will help you to make the best choices for you and your baby’s health.
Roth, C. K., Satran, L.A., Smith, S.M. (2015). Marijuana use in pregnancy. Nursing for Women’s Health 19(5) 431-437.