Every birth prior to 37 weeks of pregnancy is a premature birth. Premature births prior to 34 weeks of pregnancy are associated with significantly increased perinatal morbidity and mortality. A screening to improve prevention and treatment of premature birth is therefore useful. A fundamental component for the determination of risk factors is the patient history. A rapid second pregnancy within 12 months and a preterm birth in a previous pregnancy are considered to be the most important risk factors in the patient history. Examination of the neck of the cervix and particularly sonography provide additional information. They are particularly recommended for high-risk pregnant women or for pregnancies with existing symptoms, such as premature contractions, but are not recommended as a standard screening in the low-risk population. The same applies for the determination of biomarkers from vaginal secretions, which, in the case of symptoms, enables a better assessment of the overall situation. Laboratory diagnostics play a subordinate role in the diagnostics of premature birth.