McCarthy provided five 30-minute sessions to 600 women and found a virtual absence of postpartum depression, compared to the typical rates of 10 to 15 percent. Women with a history of postpartum depression did not develop this condition, even though an estimated 50 percent eventually do. Harmon et al also reported lower depression scores in the hypnotically treated group.

It appears that a simple intervention, hypnotherapy, has far-reaching effects both medically and socially. Some, but not all, of the above studies are randomized, have large numbers, include control groups and demonstrate statistical significance. There remains, therefore, a clear need for more research, in the use of hypnosis for childbirth preparation.

Rates of Intervention

In a randomized control trial of 42 teenagers in Florida, none of the 22 patients in the hypnosis group experienced surgical intervention compared with 12 of the 20 patients in the control group (p=.000). Twelve patients in the hypnosis group experienced complications compared with 17 in the control group (p=.047).

Harmon, Hynan and Tyre reported more spontaneous deliveries, higher Agpar scores and reduced medication use in their study of 60 women. Of the 45 Hypnosis for Childbirth clients, 38 delivered without the use of caesarean, forceps or vacuum, a rate of spontaneous birth of 84%. This is a higher than average rate of normal birth for the general population of first time mothers.

Medication Use

In a British study, 55% of 45 patients (first and second time mothers) required no medication for pain relief. In the other non-hypnosis groups, only 22% of 90 women required no medication. Two research pieces reported on 1,000 consecutive births: 850 women used hypnotic analgesia resulting in 58 percent rate of no medication. Five other research pieces reported an incidence of 60 to 79 percent non-medicated births.

A retrospective survey notes an epidural rate of 18 percent in Southern Ontario, where the epidural rate in most hospitals is 40 to 95 percent (depending on the setting) for first time mothers.

Effect of Hypnosis on labor

Hao et al in China measured the effect of nursing suggestions to labouring women and recommends that the conversation of the nurses be "controlled carefully for the purpose of advancing the birth process". This randomized control trial examined 60 first time mothers with a matched control group of 60 first time mothers and found a statistically significant reduction in the lengths of the first and second stages of labour.

Jenkins and Pritchard found a reduction of 3 hours for prim gravid women (from 9.3 hours to 6.4 hours) and 1 hour for multi gravid women (from 6.2 hours to 5.3 hours) for active labour (262 subjects and 600 controls). Pushing was statistically shorter for first time mothers (from 50 min to 37 min).

In a study that compared hypnosis and Lamaze training, 96 women chose between hypnosis (n=45) and Lamaze (n=51). The first stage of labour was shortened in the hypnosis group by 98 minutes for first time mothers and by 40 minutes for second time mothers. These women were more satisfied with labour and reported other benefits of hypnosis such as reduced anxiety and help with getting to sleep.