Objective: Adolescent marriages are those that take place before the age of 18 years or before maturity and are associated with a wide range of health and psychological problems. This study was carried out to examine the reproductive health behaviour of women who got married during the adolescent period. Methods: In this study, convergent parallel design, in which the quantitative and qualitative stages of mixed method designs can be applied simultaneously, was used. This research was carried out with 245 women included in the quantitative section and 25 women in the qualitative section. During the collection of the quantitative data, face-to-face interview and semi-structured interview techniques were used. The data were collected using the content analysis method, and descriptive statistics were used in the analysis of quantitative data. Results: The mean age at first marriage was 16.1±0.9 (range 12–17) years. Quantitative analysis showed that, to have a healthy delivery, women adopted the practices of healthy life during pregnancy (88.7%), for the birth they maintained nutrition, ensured good hygiene and performed pain coping techniques (95.0%) and maintained personal hygiene during post-partum (69.8%). Analysis of the data collected in the in-depth interview on the women’s practices on sexual life and violence against women, five themes were identified ‘healthy sex life, sexual violence, legal procedures, social support and preventive practices’. Conclusion: Women who got married at adolescent age had problems with their reproductive health characteristics and reproductive health. Midwives can take an active role in meeting the service needs for this vulnerable group, solving reproductive health problems and improving women’s health during service provision.