On many mornings, with a few puffs of pot — and one cannabis-laced chocolate-covered blueberry in the afternoon — Richelle has been able to stop the severe nausea that has accompanied her third pregnancy.

It not only ended the constant vomiting, but the San Jose mother can finally eat an entire cheeseburger — and keep it down.

“The medical field frowns on pregnant women using marijuana,’’ said the 27-year-old bookkeeper who lost 30 pounds early on because of her condition, called hyperemesis gravidarum, which also causes dehydration. “But I possibly would not have kept the pregnancy without it,’’ said Richelle, now in her 25th week of pregnancy. She asked that her last name not be used because she does not want to be publicly attacked for her beliefs.

After two decades of allowing its medicinal use, California is now one of eight states that have legalized recreational marijuana for people 21 or older. Public health officials, however, say the implications surrounding its consumption by some people — like pregnant women and adolescents, who may be more vulnerable to its potential harmful effects —  still must be addressed.

Some states — including Alaska, Washington and Colorado — require warning labels saying the product should not be used by pregnant or breastfeeding women. But California does not.

Surveys show that most Americans don’t like the idea of pregnant women using marijuana.

Richelle, of San Jose, holds a can of chocolate-covered blueberries infused with cannabis in San Jose, Calif., Wednesday, April 19, 2017. Richelle is 24 weeks pregnant and a marijuana user, using it to alleviate her nausea. (Patrick Tehan/Bay Area News Group)

A Yahoo News/Marist College poll of 1,222 adults released Monday found that 67 percent of Americans think it’s safer to use marijuana than opioids to relieve pain. But 69 percent said it’s not acceptable for pregnant women to use marijuana to reduce nausea or pain. Half of cannabis users — and 60 percent of those who have tried it — also don’t think pregnant women should use marijuana, according to the poll.

Dr. Ira Chasnoff, a professor of clinical pediatrics at the University of Illinois College of Medicine and a leading researcher in the development of children prenatally exposed to alcohol and drugs, said a range of studies supports those concerns.

“The general belief is that it’s not harmful,’’ Chasnoff said of cannabis consumption. “But there are all sorts of aspects of cognitive function — the way the brain works — that are impacted by marijuana exposure.’’

He pointed to research that shows low birth rates in babies born to women who have consumed pot during pregnancy, as well as data on higher rates of Attention Deficit Disorder and Attention Deficit Hyperactivity Disorder as they get older. Other research has shown that those offspring later in life have problems with “executive functioning,’’ or the ability to plan and complete tasks, Chasnoff said.

That’s why he believes guidelines that communicate the risk and discourage the use of medical marijuana by pregnant women — or women considering pregnancy — must be established. Research indicates that more U.S. women are now using marijuana during pregnancy, most often to treat morning sickness — which physicians say can be treated with certain medications.

A recent study in the Journal of the American Medical Association said that in 2014 nearly 4 percent of pregnant women between the ages of 18 and 44 reported having used marijuana in the past month, compared with 2.4 percent in 2002.

In Oakland, 36-year-old Sarah — who runs a cannabis consulting business with her husband — said she has been using the drug during her 17-week-pregnancy to help not only with some morning sickness but also with sciatica pain — and to curb mood swings.

Like Richelle, she takes a few puffs of a marijuana cigarette every so often, but also uses a few drops of liquid cannabis on her tongue at night. The pain disappears, she said, and she’s able to keep food in her stomach.

Sarah has read a host of studies on the potential side-effects the drug might have on her baby. So have some of her relatives, who have told her that using marijuana will “risk having my child come out dumb,’’ said Sarah, who also she didn’t want her last time published because she fears she’ll be ostracized.

But she remains unconvinced by what she calls “limited research.’’ She said that she doubted that an organically grown plant would harm her baby.

A landmark 395-page study on the health effects of cannabis and cannabinoids released in January by the National Academies of Science Engineering and Medicine also wasn’t able to draw many conclusions.

After reviewing the available research, the authors determined that the relationship between smoking cannabis during pregnancy and other pregnancy and childhood outcomes is unclear.

But they did agree that there is substantial evidence that smoking cannabis during pregnancy is linked to lower birth weight.

Sarah emphasized she doesn’t abuse the drug, adding that it also helps reduce the anxiety that comes with being pregnant.

“There is a human inside me growing, and everyone is telling me what I can and cannot do,” she said. “It creates a lot of worry.”

And in her line of work, she has also met many women who used marijuana when they were pregnant, and whose children — of all ages — seem well-adjusted.

“Everything in moderation,’’ said Sarah.

Chasnoff strongly disagrees with that view — and with patients who tell him that cannabis is natural and organic. That doesn’t mean it wouldn’t potentially harm a fetus, he said.

“We know that marijuana’s THC (tetrahydrocannabinol) crosses very readily from the blood into the brain, so even a small amount has the potential for crossing over into the fetal brain,’’  Chasnoff said.

The chemical responsible for most of marijuana’s psychological effects is drawn to fat, he said, and because the fetal brain is almost all fat, the drug remains there longer. It’s one reason why marijuana, unlike other drugs, can be detected in a person for three days to three weeks afterward, depending on the amount and concentration of cannabis consumed.

Marijuana also crosses readily into a mother’s breast milk, said Chasnoff, adding, “We have been able to measure the level of marijuana in the baby’s urine.”

Dr. Frank Lucido, a primary care physician in Berkeley who for two decades has recommended medical marijuana to his adult patients if he determines it will benefit them, doesn’t believe there is enough significant research to warrant pregnant women avoiding cannabis.

“With anything in medicine, you weigh the benefits and the risks,’’ said the 69-year-old physician. “Nobody has ever died from cannabis, but we know women die from hyperemesis gravidarum.’’

So if a pregnant patient is unable to keep food or liquids in her stomach, and marijuana would help, then he would advise it — as he does to perhaps one or two patients each year.

“I usually discourage it (smoking marijuana), because we don’t know — and smoking can cause low birth weight,’’Lucido said. “And maybe smoking (the drug) is the problem.’’

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