Mental Training and Childbirth

Background:

Experiencing labour pain is a challenge to the parturient woman and can possibly cause a traumatic birth experience, post traumatic stress syndrome, post partum depression, caesarean section or refraining from having more children.

Pharmacological pain relief methods to relieve birth pain are limited and often associated with side effects. Investigating new methods without adverse effects to relieve labour pain is therefore important.

Several studies indicate that a mental trainings method, self-hypnosis, has a positive impact on labour pain and several other birth outcomes. However, many of these studies were based on observational data with a limited amount of participants that may be prone to bias and confounding.

Aim:

The aim of this study is to examine the effect of a short antenatal course in self hypnosis on the use of epidural analgesia during childbirth.

Method:

The study is designed as an interventional single center study taking place at one of the largest birth departments in Denmark. It is a randomised, controlled, single blinded trial using a 3 arm group design.

The participants will be randomised by a voice respond program. The intervention group receives 3 antenatal classes in self hypnosis taught by midwives with qualified training in hypnosis. The course includes audio compact discs for homework in self hypnosis.

The active comparator group also receives 3 antenatal classes. The program is taught by the same midwives as in the intervention group and includes a mixture of training in different relaxation methods and mindfulness. This course also includes audio compact discs for homework.

The control group will only receive ordinary antenatal care and no additional interventions.

The data collection will be based on questionnaires, register data, medical records and biological material.

The endpoints are:

Primary:

• The use of epidural analgesia during birth

Secondary:

• Length of birth
• Birth progression at arrival at birth department
• Birth experience (pain, control, anxiety)
• Medical interventions during birth including mode of delivery
• Hemorrhage during birth
• Saliva cortisol profile at birth and 6 weeks p.p.
• Infection during birth and the first 6 weeks p.p. (mother and child)
• Postnatal depression
• Breastfeeding duration
• Child's condition and wellbeing at birth and 6 months later
• Future mode of delivery

At the start of the study, we performed our power calculations based on the fact that 44% of all primiparas at Aarhus University Hospital Skejby in 2007 had received epidural analgesia. We hypothesized that the observed frequency of epidural analgesia would be 25 % in the intervention group, 35 % in the placebo effect group and 40 % in the placebo group.

According to these power calculations, we should include 328 participants in the hypnosis group, 328 participants in the active comparator group and 152 participants in the control group to obtain a power of 80 % (α 0.05 (two sided)) in detecting a difference of 5 percentage points (relative risk (RR) 0.71) between the intervention and the active comparator group. By including 152 participants in the control group we would have a larger power to detect a difference of 15 percentage points (RR 0.63) in the use of epidural analgesia between the intervention and the control group.

Because we expected that some participants would develop medical conditions that required epidural analgesia during delivery, give birth prior to receiving their allocated intervention, or give birth by caesarean section, we decided to increase the sample size by 10% in all groups to a total of 890 participants.

In 2010, the study board experienced that in 2009 the general frequency of epidural analgesia in primiparas giving birth at Aarhus University Hospital Skejby had decreased to 34%.Therefore it was decided to adjust the sample size according to this new information.

When the sample size was adjusted we maintained the same sample ratios between the groups and hypothesized that the observed frequency of epidural analgesia would be 22 % in the intervention group, 30 % in the placebo effect group and 32 % in the placebo group. To obtain a power of 80 % (α 0.05 (two sided)) in detecting a difference of 8 percentage points (RR 0.73) between the intervention and the active comparator group in the use of epidural analgesia and a difference of 10 percentage points (RR 0.68) between the intervention and the control group we should include 446 participants in the hypnosis group, 446 participants in the active comparator group and 226 participants in the control group, in total 1097 participants. Again, we further increased the sample size with an extra 10% to account for those women that would not be able to comply with their allocated treatment because of obstetric conditions and reached a sample size in total of 1208.

Analyses will primarily be performed as "intended to treat". Secondary analyses according to "as treated" and preplanned subgroup analysis will also be performed.