Many physiological and psychological changes occur during pregnancy. Sleep and stress are among these changes and can negatively impact the pregnancy process. Yoga can improve sleep quality and stress levels during pregnancy. The purpose of this study was to evaluate the effects of yoga, implemented in the third trimester of pregnancy according to World Health Organization guidelines, on sleep and stress.

Pregnancy is defined as a period of both physiological and psychological changes in women. Although pregnancy and childbirth are natural processes, the physical, mental, and emotional adaptive changes that occur during this time can significantly impact a woman's health and pregnancy outcomes. Sleep problems are common during pregnancy. Toward the end of pregnancy, women often experience frequent nighttime awakenings, insomnia, and restless sleep. During pregnancy, women undergo bio-physio-psychosocial changes that can lead to increased stress. In order to prevent adverse outcomes, it is important to manage stress in pregnant women and implement interventions aimed at reducing high cortisol levels.

Yoga can be defined as a system of stretching exercises and postures (asanas) combined with deep breathing (pranayama) and meditation, aiming to unify the mind, body, and spirit.

There are studies that have evaluated the effects of yoga practice during pregnancy on sleep and stress. None of these studies have reported any negative effects of yoga on pregnancy. In all studies, yoga was applied with varying frequencies, durations, and techniques. However, no study has been found that evaluates the effects of a yoga program conducted in accordance with the recommendations of the World Health Organization (WHO, 2023) on both sleep and stress. Therefore, the aim of this study is to evaluate the effects of yoga, implemented during the third trimester of pregnancy in line with WHO guideline recommendations, on sleep and stress.

Inclusion Criteria:

• Voluntarily agreed to participate in the study,
• Aged between 18 and 35 years,
• In the third trimester of pregnancy (between 29 and 42 weeks of gestation),
• Able to read and write in Turkish,
• No prior experience with yoga practice.

Exclusion Criteria:

• High-risk pregnancy,
• In the first or second trimester,
• Multiple pregnancy,
• Any condition that prevents yoga practice (e.g., restrictions on physical activity),
• Previous experience with yoga practice

Because of the behavioral and observable characteristics of the intervention (yoga in the third trimester of pregnancy), neither assessment nor blinding of investigators was performed.