Pregnancy is a new experience and a time of big changes in every woman's life. Particularly big changes occur in the life of a woman who did not plan her pregnancy. In such a situation, the social support that a woman should receive from the society in her environment is especially important. Many studies have proven that social support and its quality have a major impact on a woman's mental health, but also on pregnancy. Due to the lack of social support, some women decide to terminate their pregnancy, which leads to new burdens for their mental and physical health. The aim of this research was to examine the attitudes of women who had an unplanned pregnancy in the territory of the Republic of Croatia, on whether they received sufficient quality social support and whether it had an impact on their mental health, possible complications during pregnancy and the outcome of the pregnancy itself. In addition, one of the goals was to investigate the connection between the quality of social support and the sociodemographic characteristics of the respondents. 214 respondents with an unplanned pregnancy participated in the research, and it was conducted using an online questionnaire created for the purposes of this research. The results of this research showed that the quality of social support provided to women with an unplanned pregnancy in the Republic of Croatia is still insufficient and that it can have an important impact on the pregnancy, the decision to maintain or terminate the pregnancy, but also on the pregnant woman herself, specifically her mental health.