Twenty-three states in America have legalized marijuana in either medicinal or recreational form. Because it is more readily available, more people are experimenting with the substance, even pregnant women. Ingesting any type of drug during pregnancy is harmful to the mother and the baby and is bound to have adverse effects. A study published in Reproductive Toxicology states that one of these effects could be pre-term birth.

The team of researchers from the University of Adelaide that led this study were focused on determining whether there is a direct link between marijuana use during pregnancy and pre-term birth. To do so, they analyzed data from 5,500 pregnant women in the countries New Zealand, Ireland, the United Kingdom and Australia. All of these women were participants in the Screening for Pregnancy Endpoints study (SCOPE).

The research showed that 236 of the participants had pre-term births and 5.6 percent of the participants admitted to using marijuana during their pregnancies. It also found that continued marijuana use up to 20 weeks pregnancy was linked to a five-fold increase in risk of pre-term births occurring. Many of these pre-term births were preventable.

Some women that were smoking marijuana during pregnancy said they were doing so to prevent nausea. The study recommends that this is stopped, and all use of the drug is discontinued.