Teenagers who use cannabis every day are six times more likely to give birth prematurely, a new study claims.
Researchers followed 665 people, who gave regular information on their tobacco and cannabis use between ages 14 to 29, and went on to have a total of 1,030 children.
The team from the University of Bristol and University of Melbourne, Australia, found children whose parents had used cannabis daily between the ages of 15 and 17 were born on average more than a week earlier than those whose parents reported no use.
George Patton, fellow in adolescent health research with the University of Melbourne and Murdoch Children’s Research Institute, said there was a pressing need for better research into the area “given growing political and industry drivers for legalisation of use”.
The study, published in the journal Scientific Reports, considered both mothers and fathers of the babies involved, which was said to be important because although teenage boys are more likely to be daily users of cannabis, men are largely overlooked in relation to public health messaging regarding substance use and birth outcomes.
Dr Lindsey Hines, from Bristol Medical School, said there was evidence, mainly from animal studies, that cannabis exposure could affect reproductive organs and fertility, as well as interfering with biological processes governing DNA activity.
“[It] could be that regular cannabis exposure in teenage years, a critical period for reproductive development, is impacting reproductive function years later,” she said. But it was also possible that people who used cannabis daily as teens were then doing something else in their 20s that raised the risks for preterm birth when they went on to have children.
The link between cannabis consumption and early births was not found in those between the ages of 20 to 24 or at age 29. Hines said this made it less likely that the relationship between teenage cannabis use and preterm birth was driven by continuation of use as frequent smokers aged.
