When hypnosis is used to treat diseases, addictions or symptoms, we call it hypnotherapy. In the process of hypnosis therapist play an important role. He or she has to have relaxing voice and asks a person to focus attention on a specific point or idea, which results in a sleep- or trancelike state. This is the state in which the patient is more receptive to suggestions. There haven't been many studies on hypnosis that could prove hypnosis is a successful treatment for infertility. However, there are sources like Fertility and Sterility Journal that claim that hypnosis doubles a woman's chance of getting pregnant when used in conjunction with in vitro fertilization.
For example, scientists from Israeli University of Soroka observed women who were undergoing IVF. One group of women was hypnotized during the embryo transfer stage, which is a very stressful process that is followed by uterine contractions, while the control group wasn't hypnotized during the stressful process. This study showed that women who were hypnotized had as much as 30% success rate, comparing to the group of women that weren't hypnotized during embryo transfer stage that had a success rate lower for 50% - only 14% of un-hypnotized women conceived.
This study and many hypnotizers suggest the main benefit of hypnotherapy is relaxation, which in case of infertility and IVF because of hypnotherapy's effect on anxiety and stress contributes to reduced uterine contractions. Unfortunately, most scientists aren't convinced, and many of them point to research flaws that could negate the findings. Additionally, the American Society for Reproductive Medicine said it has no formal position on hypnosis and fertility, and they claim more research needs to be done to see if therapy actually works. However, the study from Israel has made an impact by encouraging further studies on the effects of hypnotherapy on infertility.