Postnatal period is an important developmental transition period for women. Stress in the postnatal period is one of the most common mental health problems and most mothers report experiencing stress in the perinatal period. In addition, stress and negative mental health also threaten breastfeeding self-efficacy. The postnatal period is an important stage in terms of early initiation and maintenance of breastfeeding. Breastfeeding self-efficacy is a mother's perceived confidence in her ability to breastfeed her newborn baby. Therefore, midwives are expected to assess women and identify women in need of supportive interventions and consciously contribute to their treatment. Another common problem in the postnatal period is poor sleep quality. It was determined that an increase in sleep quality and perceived social support positively affected breastfeeding self-efficacy of postpartum women. In addition, poor sleep quality poses a threat for negative mental health outcomes for women in the postpartum period. Previous studies reflect mothers' desire for non-pharmacological interventions and a high degree of satisfaction with these therapies. Laughter therapy, one of the main non-pharmacological interventions, is recognised as a universal approach to reduce stress and anxiety. The postnatal period is a fragile period with physical and psychological changes as well as hormonal changes in the mother. Poor mental health of the mother poses a danger to the well-being of the mother and the baby. Mothers in the postpartum period need low-cost, easily accessible preventive interventions to prevent these problems. In this context, the aim of this study is to determine the effect of laughter therapy given to mothers in the postpartum period on perceived stress, sleep quality and breastfeeding self-efficacy level in mothers.

The postnatal period is an important developmental transition period for women and mothers experience various difficulties. Therefore, midwives are expected to assess women and identify women in need of supportive interventions and consciously contribute to their treatment. Previous studies reflect mothers' desire for non-pharmacological therapies and a high degree of satisfaction with these therapies. Laughter therapy, one of the main non-pharmacological interventions, is recognised as a universal approach to reduce stress and anxiety. Laughter therapy is a new, simple, cost-effective, non-invasive, non-invasive, widely available online, easily accessible and effective method. Laughter therapy has been applied to many different patient populations and healthy individuals in a variety of settings, and studies have reported benefits such as improved sleep quality, decreased depression, pain and stress hormones, improved mood and life satisfaction, increased prenatal attachment and breastfeeding self-efficacy. These benefits document the positive role of laughter therapy in improving the quality of life of individuals. Laughter therapy is a type of cognitive-behavioural therapy that can improve physical, psychological and ultimately quality of life. Laughter therapy can be used for both preventive and therapeutic purposes. In contrast, the negative effects of laughter and humour are negligible.

In conclusion, laughter is a human and universal value. Using laughter effectively to improve well-being and facilitate adaptation to the changes experienced in this period can significantly improve quality of life. Mothers in the postpartum period need low-cost, easily accessible preventive interventions to prevent these problems. However, to achieve this, health professionals need to be aware of the most appropriate evidence-based interventions. The number of studies investigating the effect of laughter therapy on women's health is limited in Turkey. In order to increase evidence-based data, there is a need to investigate the potential effectiveness of laughter therapy interventions in terms of women's health. In this context, the aim of this study was to determine the effect of laughter therapy given to mothers in the postnatal period on perceived stress, sleep quality and breastfeeding self-efficacy level. It is thought that the results of this study will guide midwives to be aware of the effectiveness of laughter therapy and to plan interventions to improve the quality of life of mothers.

Inclusion Criteria:

• At least primary school graduate
• Over the age of 18
• Those who volunteer to participate in the research
• Heterosexual
• Having a single and healthy baby
• Postpartum 1-12 month old baby
• Women who can use Zoom program

Exclusion Criteria:

• Those who do not speak Turkish,
• Those with hearing and visual impairments,
• Those with mental disabilities,
• Those diagnosed with a known psychiatric disease,
• Mothers who do not breastfeed
• Mothers who have babies with disabilities and chronic health problems
• Women with physical conditions that prevent them from participating in laughter yoga sessions (respiratory distress, persistent cough, vertiligo, severe heart disease, hemorrhoids, any type of hernia such as neck, waist or inguinal hernia, severe back pain, urinary incontinence, epilepsy, etc.),
• Women who use medication or use another non-pharmacological method to reduce stress.

Women who develop an acute health problem in themselves or their babies, who have a sudden hospitalisation of the mother or baby, mothers who lose their babies, women who do not attend all of the laughter therapy sessions and women who cannot be reached after the application will be excluded from the study.

breastfeeding mothers in the postpartum period

In the study, the process of assigning mothers to the laughter therapy and control groups was done by simple randomisation to ensure similarity between the groups. To ensure randomisation in the study, a table of random numbers was created by dividing into two groups according to the number determined on https://www.randomizer.org/. Two random number series (set 1 and set 2) between 1- 120 were created in the system using the Random Integer Generator method in the Numbers subheading of this site. The 120 women who met the inclusion criteria were assigned to 60 laughter therapy groups and 60 control groups in a 1:1 ratio by simple randomisation method. Which group was the intervention or control group was determined by drawing lots at the beginning of the study. The mothers included in the study did not know which group they were in at first. After the individuals who met the inclusion criteria and volunteered to participate in the study were determined, the participants were assigned