DENVER - State health officials on Tuesday told lawmakers that there have not been significant health problems as a result of marijuana legalization.

Dr. Larry Wolk, executive director and chief medical officer for the Colorado Department of Public Health and Environment, said marijuana-related hospital visits represent fewer than 1 percent of all emergency room hospitalizations in the state. He added that alcohol and prescription drug visits far exceed that number.

Wolk spoke to lawmakers during a presentation before the House Health, Insurance and Environment Committee. He also spoke of the medical benefits to marijuana.

"Cannabis has some fairly well documented medical benefits, but obviously there is a clear need to contribute meaningfully to the research that is available," Wolk said.

Colorado has set aside $10 million over five years from medical marijuana revenue to support at least eight research grants. Studies have been approved for tremors related to Parkinson's Disease, impacts to post-traumatic stress disorder, and treating pediatric epilepsy, among other applications.

With an estimated 115,467 active patients on the medical marijuana registry, health officials are carefully watching how the legalization experiment unfolds.

Voters approved medical marijuana in 2000, but use did not proliferate until dispensaries started operating above ground thanks to rules established in 2009. Full marijuana legalization, approved by voters in 2012, opened the door even more.

But health concerns continue. Lawmakers on Tuesday were also asked to address how marijuana might impact pregnancies.

Rep. Jack Tate, R-Centennial, introduced a measure that would have required dispensaries to display a sign that warns pregnant women about the potential dangers of using cannabis when carrying a child.

But Tate asked the House Public Health Care and Human Services Committee to kill his measure after hearing concerns from women over requiring dispensary workers to inquire as to whether a woman is pregnant. Some women found that insulting.

"It's probably one of the most insulting things you can ask a woman, or say to a woman," said Jessica LeRoux, a well-known cannabis activist. "Most pregnant women are extremely concerned about their health. This is just so stupid to assume that they don't know this inherently."

Wolk, however, said health officials remain concerned about marijuana impacts to pregnancies. A 13-member Colorado marijuana public health advisory committee recently found that maternal use of marijuana during pregnancy is associated with negative effects on exposed children, some of which doesn't appear until adolescence.

"The harms or ills are somewhat unknown, other than that there aren't studies in this particular area, but ... we are concerned about the risk to the pregnant woman and to the developing person inside," Wolk told lawmakers.

Meanwhile, state regulators with the Department of Revenue, continue to grapple with how to regulate cannabis-infused edibles, such as liquids and oils. The Legislature last year required that rules be adopted by January 2016 in an effort to make infused products readily identifiable.

But a work group that met over the summer to craft such rules hit a wall, unable to identify a standard symbol, or even determine whether an imprint is necessary.

Part of the problem is that it is impossible to stamp products that are liquid - like soda - or sold in bulk - like individual pieces of granola.

The state can't ban those products because of constitutional protections enacted when voters legalized recreational marijuana in 2012.

As a result, regulators are asking lawmakers for some assistance.

"It will be very difficult for this working group to come to consensus on what to do to move forward without some clear guidance," said Barbara Brohl, executive director of the Department of Revenue. "We would really like your guidance in laying it out a little more clearly."

pmarcus@durangoherald.com