During pregnancy, the risk of periodontal disease is increased. The combination of bacteria in plaque and increased female sex hormones in the bloodstream can cause intense symptoms, even when it comes to smaller amounts of plaque. Some of the most common periodontal diseases that occur during pregnancy are gingivitis, periodontitis and pregnancy granuloma. In periodontitis, periodontal pockets act like a focal point that can affect the distant organs. Therefore, with persistent periodontal disease, risks of adverse pregnancy outcomes arise, such as preeclampsia, premature birth, low birth weight, infection, gestational diabetes, and morbidity. Risk factors promote the onset and progression of periodontal disease itself. They can be divided into unmodified factors such as genetic factors, age, ethnicity, gender and systemic diseases; and into modified factors such as socioeconomic status, oral hygiene, obesity, stress, specific hormonal changes during pregnancy and smoking, which has detrimental influence on the foetus due to the danger of tobacco smoke. Treatment of periodontal disease can be achieved through non-surgical periodontal therapy that is safe during the gestational period, while the second trimester is most conducive to its implementation. It is extremely important to take into consideration the patient's medical history, to make a thorough clinical examination and to devise a therapy plan accordingly. X-ray recording can be performed if necessary, and analgesics, anesthetics and antibiotics can be used, with the exception of tetracycline. In addition to periodontal therapy, it is important to educate pregnant women on thorough oral hygiene, using soft toothbrushes and interdental agents with regular examinations at the dentist. Keywords: adverse pregnancy outcomes; periodontal disease; periodontal therapy; pregnancy