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Exploring Potential Adverse Effects of Marijuana Use During Pregnancy

Doug Dollemore

Torri Metz
Torri Metz, MD, MS, will evaluate the effects of marijuana use on the health of mothers and unborn children throughout pregnancy. Photo credit: Charlie Ehlert


In one of the most comprehensive examinations to date of marijuana use during pregnancy, Torri Metz, M.D, a University of Utah Health associate professor of obstetrics and gynecology, will evaluate the drug's effects on the health of both mother and child throughout gestation.

The study, supported by the National Institute on Drug Abuse, will focus on the risk of adverse outcomes for newborns, including placenta dysfunction and inhibited fetal growth in the womb. It will also assess whether marijuana increases the probability of preeclampsia and gestational hypertension among expectant women.

Marijuana is the most commonly used drug during pregnancy, but little is known about its potential effects on mother and child. Previous studies have found substantial evidence that the drug can lower birth weights. However, these studies have relied on self-reporting from mothers-to-be or clinical toxicology testing rather than evaluating biological samples directly.

To remedy that problem, Metz and her colleagues will study biological samples previously collected from more than 9,200 women who participated in the Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-Be. They will evaluate urine samples from the first, second, and third trimester of pregnancy. They will also assess a segment of umbilical cord to look for marijuana metabolites.

"In this study, we will be able to more rigorously evaluate the relationship between marijuana use and adverse pregnancy outcomes by testing for marijuana metabolites in biological samples across the course of pregnancy," Metz says. "Not only will we be able to examine if any use influences outcomes but we can also look at whether timing and amount of use is important."

As a clinical researcher, Metz is interested in the impact of marijuana use in pregnancy on the mother and newborn, maternal congenital heart disease, and factors influencing mode of delivery.