Is smoking pot OK for moms-to-be? Experts at the American Medical Association (AMA) say no, and they’re pushing for the placement of warnings on all medical and recreational marijuana products sold in the United States to send out the message, NBC News reports.

The group based its decision on recent studies presented by the American College of Obstetricians and Gynecologists (ACOG) at the AMA’s recent policy meeting in Atlanta. The data presented suggested that women smoking marijuana while pregnant or breastfeeding may be linked to a litany of negative health effects in young children. The AMA also cited recent data that showed nearly 5 percent of mothers nationwide reported using the drug while pregnant—a rate that climbed to 28 percent among some urban, low-income women.

Studies have linked marijuana use during pregnancy with childhood attention problems and kids getting lower scores on problem-solving tests. Studies have also found THC, the main active psychotropic ingredient in pot, in the breast milk of women who smoke. What’s more, findings showed THC may affect both the quality and quantity of breast milk mothers produce.

Those who support warning labels on pot product observed that alcohol and tobacco packaging sport similar labels. “So why not do the same thing with marijuana since it is the most commonly used illicit drug during pregnancy?” asked Diana Ramos, MD, a Los Angeles–based physician and member of ACOG.

But those against warning labels say evidence of the harm marijuana poses to unborn children is still very weak. Many women use the drug to stave off nausea, chronic pain or depression during or after pregnancy. But warning label advocates believe erring on the side of caution made the most sense.

For more information about current research on medical marijuana, click here.