Study links effects of prenatal alcohol and drug exposure with placental development

In the United States, prenatal alcohol exposure (PAE) is the most common preventable cause of developmental delay. Animal studies have shown some of the adverse effects of PAE on placental development, but few studies have examined these effects in humans. This is the first study to examine the effects of prenatal exposure to methamphetamine, marijuana, and cigarette smoking on human placental development.

Researchers collected placentas from 103 Cape Coloured (mixed ancestry) pregnant women recruited at their first antenatal clinic visit in Cape Town, South Africa. Of these, 66 heavy drinkers and 37 non-drinkers were interviewed about their alcohol, cigarette smoking, and drug use at three antenatal visits. A senior pathologist, blinded to exposure status, performed comprehensive pathology examinations on each placenta using a standardized protocol. In multivariable regression models, effects of prenatal exposure were examined on placental size, structure, and presence of infections and meconium.

Results show that alcohol, methamphetamine, and marijuana were associated with distinct patterns of pathology, suggesting that different mechanisms mediate their effects on placental development. Alcohol exposure was related to decreased placental weight and a smaller placenta-to-birth weight ratio. By contrast, methamphetamine was associated with larger placental weight and a larger placenta-to-birth weight ratio. Marijuana was also associated with larger placental weight. In addition, alcohol exposure was associated with an increased risk of placental hemorrhage. Finally, alcohol and cigarette smoking were associated with a decreased risk of intrauterine passing of meconium, a sign of acute fetal stress and/or hypoxia; methamphetamine, with an increased risk. These findings may be important in the long-term teratogenic effects of prenatal alcohol and drug exposure.


Research Society on Alcoholism


  1. Storm Crow Storm Crow United States says:

    So, the only effect noted for cannabis was a healthy increase in placental weight? Interesting!  And then when you add in these results.....

    "Marijuana influences visual development" (Scoop) where cannabis PROTECTS against some of the negative effects of fetal alcohol syndrome.  

    "Medical marijuana: a surprising solution to severe morning sickness" (Mothering). And as a woman, I can tell you it works!        

    And in  “Mortality Within the First 2 Years in Infants Exposed to Cocaine, Opiate, or Cannabinoid During Gestation” (PubMed), they found “Within the first 2 years of life, 44 infants died: 26 were drug negative (15.7 deaths per 1000 live births) and 18 were drug positive (13.7 deaths per 1000 live births). The mortality rate among cocaine, opiate, or cannabinoid positive infants were 17.7, 18.4, and 8.9 per 1000 live births, respectively.”
    Allow me make that even clearer, so there is absolutely no confusion-

    No drugs at all babies- 15.7 deaths per 1000 live births
    Cocaine-exposed babies – 17.7 deaths per 1000 live births
    Opiate-exposed babies – 18.4 deaths per 1000 live births
    Cannabis-exposed babies- 8.9 deaths per 1000 live births

    An online article that goes into detail about this study is “Pregnant Women Smoking Pot Could Reduce Infant Mortality” (opposingviews).

    However, smoking anything is bad for the baby, but cannabis can be "vaporized", eaten, or made into tinctures to avoid the hazards of smoking.

The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of News Medical.
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