Marijuana Use Doubles Risk of Premature Birth
A press release from the University of Adelaide has found a link between premature birth and mothers who used marijuana before becoming pregnant. The study included 3,000 women from both Australia and New Zealand.
Premature birth was defined in the study as a delivery that occurred at least three weeks before the calculated due date for the birth. Such births are known to have lifelong consequences, with increased risks for a variety of physical and mental health problems.
Other risk factors were determined as well.
The highest risk for a preterm delivery was a family history of low birth weight babies (six times the risk). Marijuana use more than doubled the risk of a premature birth. Other risk factors equivalent to marijuana use were: a history of pre-eclampsia, vaginal bleeding, and diabetes.
In the United States, this study may give researchers a target to see if the results hold up here. If they do, it would give significant ammunition to those who have cautioned against legalizing marijuana. On the medical front, it would also mean marijuana would have to be limited in those who might become pregnant – meaning physicians would have to be more cautious about writing prescriptions for medical marijuana. Women of child bearing age would have to weigh the risks against the benefits.
Critics of the study
Critics point out that the link may indicate something other than a cause and effect relationship. In other words, mothers who have smoked marijuana may have other behaviors that lead to the increased risk and not specifically cannabis use. No direct mechanism has been put forward to explain the link. The usual rule in science is that “correlation is not causation.”
One further concern, should the relationship hold up, is that mothers who smoke marijuana could be charged with chemical endangerment of their unborn child. Laws to this effect have already been used when babies test postitive for illegal substances like cocaine or heroin. Since marijuana is detectable in hair samples many months after someone has used the drug, mothers could conceivably be blamed after a premature birth if they test positive.
The study author said, “Our ultimate aim is to safeguard the lives of babies and their health in the longer term."