Whether Kate is actually undergoing hypnosis is up for debate, given the source of the report. But the claim raises questions of whether hypnotherapy has been shown to be effective as a treatment for women suffering from hyperemesis gravidarum.
Medical studies do not offer conclusive evidence. In 2010, researchers at Queen's University of Belfast in Belfast, Northern Ireland, completed an examination of six different studies on hypnotherapy and acute morning sickness and found encouraging results for its use as a treatment. However, the researchers concluded that the quality of evidence was not sufficient to establish whether hypnosis is truly effective.
According to Dr. Tony Chon with the Mayo Clinic's Complimentary and Integrative Medicine Program, studies on hypnotherapy's effectiveness have shown mixed results. However, he told The Huffington Post that enough anecdotal evidence exists to suggest that the method can be a help to women, especially when so few treatment options exist for acute morning sickness.
"There's a lot of misconceptions about hypnosis, where everything is in dark room and someone's going to be swinging a clock in your face and youre going to be barking like a dog," Chon said to HuffPost.
Instead, he explained, the practice should relax the mind, making the subject more open and receptive to positive suggestions. Since morning sickness conditions the brain to associate food with nausea, hypnotherapy could possibly recondition that response, according to Chon.
"When someone is going through a trance with hypnosis, then you're kind of trying to change the way someone thinks about food," he said. "Rather than saying you're going to get nauseaus, you're saying the food that you see from this point on is going to be very nutritious, it's going to be good tasting, it's going to lead to a positive pregnancy."