Introduction: Antenatal depression occurs in 10-20 % of women and is one of the more serious public health problems, as it has been mostly unrecognized and untreated during pregnancy, which can lead to various obstetrical complications for the woman and child. One of the complications is premature birth, which is one of the biggest problems in perinatology. Purpose: The purpose of the diploma work is to study literature in the field of depression in pregnancy and premature birth and to determine what is the impact of untreated and with antidepressants treated depression in pregnancy on premature birth. Methods: In the diploma work, we used a descriptive method of work with a systematic review of literature in the time frame between 2008 and 2018. The literature was searched in the Slovenian and English languages within the COBISS, Science Direct, DiKUL, PubMed, Springer Link and Cochrane databases with the keywords »depresija v nosečnosti«, »antenatalna depresija« AND »prezgodnji porod« and »depression in pregnancy«, »antenatal depression«, »depression during pregnancy« AND »preterm delivery«, »preterm birth«.. Results: Depression in pregnancy is indirectly and directly associated with premature birth. Depression affects premature birth directly through the impact on the HPA axis and consequently on the hormonal balance. Indirectly, due to unhealthy behaviors that are typical for pregnant women with depression and with the impact of antidepressants on premature birth. Taking antidepressants, especially in the third trimester, increases the risk of premature birth more as depression itself. The longer the period of antidepressants usage during pregnancy, the higher the risk for preterm birth. On the other hand, more intense the depression, greater the risk for premature birth. Discussion and conclusion: Depression has a significant effect on premature birth, as 15.5% of pregnant women with depression have babies that are born prematurely. It is crucial that midwives and other health professionals have the knowledge of the link between depression and premature birth. Therefore they can plan and implement strategies to improve the mental health of pregnant women, thus reducing the risk of premature birth. Further research is needed for guidelines on the prevention of pregnancy depression and prevention of preterm birth in connection with depression.