Researchers have shown that the use of cannabis during pregnancy can be linked to a series of health problems for the infant, including low weight and the need for intensive care. The short story: don’t smoke it if you’re pregnant.

Photo by Flickr user ashton.

Cannabis is the drug of choice in developed and developing countries, with 147 million people or 2.5% of the world population consuming cannabis on a regular or semi-regular basis. Thankfully, it’s one of the safest drugs out there, not being linked to any acute health problems. But as it becomes more and more acceptable, it’s important to study its effects in a wider setting.

Pregnancy is an extremely delicate phase. What women ingest and inhale when they are pregnant can have drastic effects on the health of the infant. An inadequate nutrition may cause malformations or medical problems in the fetus, and neurological disorders and handicaps are a risk that is run by mothers who are malnourished. At the same time, smoking, alcohol, caffeine, using certain medications and street drugs can negatively and irreversibly affect the development of the baby, especially in the early stages of pregnancy. This is not the first study to quantify the effects of consuming cannabis during pregnancy, but it is one of the widest and most comprehensive reviews to date.

Jayleen Gunn, from the University and Arizona scanned 7 electronic databases containing 24 studies, including the effects of taking cannabis during pregnancy on maternal and fetal outcomes.

The most common problem was anemia. Anemia is a deficiency of red cells or of haemoglobin in the blood, resulting in an overall weakness. There was a strong connection between cannabis consumption and anemia, with several studies finding a strong connection between the drug and anemia. The study reads:

“Anaemia was the most widely discussed maternal outcome in the cannabis-pregnancy literature. Women who used cannabis during pregnancy may have an increase in the odds of anaemia compared with women who did not use cannabis during pregnancy.”

Furthermore, babies exposed to cannabis in utero had decreased birth weight and were more likely to
“need placement in the neonatal intensive care unit or intensive care unit” compared with infants whose mothers did not use cannabis during pregnancy. Infants exposed to cannabis in the womb were 77% more likely to be under weight at birth and twice as likely to need intensive care.

There are a couple of limitations to this study however. Women who consumed cannabis while pregnant were also more likely to consume tobacco or alcohol, so it’s difficult to separate the effect of cannabis alone (consumers of other drugs were not included in the study). Also, many studies reported unique maternal and fetal outcomes which were not included in other studies, so were not included in this analysis. It’s hard to draw definite conclusions, but the bottom line is simple: there’s a really good chance cannabis consumption during pregnancy causes problems for the baby. So if you want to be on the safe side, just don’t do it.

Journal Reference: Prenatal exposure to cannabis and maternal and child health outcomes: a systematic review and meta-analysis. [You can read the full article here]