Study author Brianna Moore, an assistant professor at the Colorado School of Public Health in Aurora, Colorado, said that "there is this misconception that cannabis is safe," reports CNN.

 

"So some women may use it in pregnancy, thinking that it's a safe alternative to other medicines, even prescribed medications," Moore said.

 

"Yet studies show connections between marijuana use during pregnancy and low-birth weight in babies and behavioural problems later in childhood, and there may be links to glucose and weight issues as well," Moore added.

 

Past studies have shown the use of cannabis during pregnancy is linked to abnormal neurological development, autism and hyperactivity, attention issues, and other cognitive and behavioural issues in children, according to the US Centers for Disease Control and Prevention (CDC).

 

Expectant mothers in the study, published in The Journal of Clinical Endocrinology and Metabolism, were recruited in Colorado through Healthy Start, a national programme designed to improve health outcomes before, during and after pregnancy.

 

Of the 103 women who were tested during pregnancy, 15 per cent had detectable levels of various cannabinoids in their urine, including THC (tetrahydrocannabinol), a chemical in the marijuana plant that has psychoactive properties, creating a "high".

 

Levels of CBD (cannabidiol) were also found. The chemical CBD is marketed over the counter and online as being "nonpsychoactive" and a safe option for anxiety, depression, sleep, pain, nausea and more. Many CBD products are made from industrial hemp, a type of cannabis plant that has little THC.