Pregnant women should not use cannabis, new US medical guidelines say

A container of THC flower at Kid Rock’s Rock the Country festival in Rome, Georgia. Marijuana during pregnancy is linked to poor birth outcomes and developmental delays in children, a leading medical society advised. Photo / Nicole Craine, The New York Times

Women who are pregnant, planning a pregnancy or breastfeeding should be screened for cannabis use and strongly discouraged from it, the American College of Obstetricians and Gynaecologists said in new clinical guidelines published at the weekend.

Cannabis use during pregnancy has been rising for years. Many women rely on the drug to cope with nausea and other pregnancy symptoms.

But the United States college warned that mounting evidence linked cannabis to preterm births, low birth weights, and a greater need for neonatal intensive care, as well as neurocognitive and behavioural problems in children.

“Patients are often using cannabis to help with some kind of medical ailment, not recreationally — in their mind, they think it’s a more natural way to deal with a medical problem,” said Dr Melissa Russo, an author of the new guidance.

“But there are lots of natural things that are not safe,” Russo said.

There are no studies demonstrating that cannabis is effective for pregnant or lactating women, she added, “and research now shows there are potential adverse effects”.

The college warned against blood or urine tests for cannabis screening.

Instead, it urged physicians to talk with women about their habits, and to encourage them to stop using marijuana as soon as possible while offering alternative therapies for medical ailments.

The screening should be universal in an effort to avoid bias and racism, the college said.

It noted that pregnant black and Hispanic women are four to five times as likely as white women to be tested for drug use.

Black women are almost five times as likely to be reported to child protective services for suspected drug use.

The new guidelines say that cannabis should be discouraged among breastfeeding women, but that breastfeeding should continue even with use of the drug because the benefits most likely outweigh the potential risks.

“We cannot be rigid in our approach,” said Dr Amy Valent, another author of the guidelines, noting that breastfeeding is important for many mothers.

Studies have found that 4% to 16% of women use cannabis during pregnancy, with rates of up to 43% in women age 19 to 22.

Women in the first trimester are the most likely to turn to cannabis as they cope with nausea and vomiting, studies show.

A recent analysis of 51 studies involving millions of pregnancies found that prenatal cannabis use almost doubled the incidence of low birth weights among babies.

It increased the incidence of preterm births by 50%, and of the number of babies born small for their gestational age by 57%.

The review also found evidence suggesting that prenatal cannabis might be tied to an increased risk of newborn death during or shortly after birth.

Dr Cara Poland, an addiction medicine specialist who runs a perinatal clinic in Grand Rapids, Michigan, said studies had linked prenatal exposure to cannabis to an increased risk of poor attention, impulse control and visual-motor co-ordination in children, as well as to increased odds of attention deficit hyperactivity disorder in middle childhood.

There is also some evidence that children exposed prenatally may be more likely to develop anxiety and depression, she said.

“As permissibility in the social environment increases, people think that cannabis use is lower risk and tend to use it more,” Poland said.

Yet levels of THC, the psychoactive ingredient in cannabis, have increased three- to fourfold in recent decades.

“We know that THC crosses the placenta and concentrates in foetal tissue, especially the brain,” Poland said.

“That means even small amounts may carry a risk today that is greater than previously.”

“We don’t have evidence for any amount of cannabis being proven safe in pregnancy, so the safest choice is to avoid it completely,” she added.

This article originally appeared in The New York Times.

Written by: Roni Caryn Rabin

Photograph by: Nicole Craine

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