Introduction: Drugs can cause change in mental and body activity because of their special chemical structure. The main reason for drug abuse may be easy accessibility and social acceptability. If a person becomes addicted to drugs it means the presence of physical and mental addiction. The tolerance occurs when drug is used repeatedly over time, so the body starts to adapt. Pregnant drug users are regarded as high risk group of pregnant women, therefore is very importatant that they are carefully treated during pregnancy and postpartum period. Purpose: The purpose of the diploma work is to present the influence of drugs on pregnancy and fetus and to present the support treatment of pregnant women addicted to drugs. Methods: In the diploma work we used the descriptive method of work. It was based on collecting scientific and technical literature and its critical reading. We used domestic and foreign research databases, named: Cobiss, Cinahl, PubMed, Medline and ScienceDirect, with time limitation between years 2008 and 2018. We used the following keywords: addiction in pregnancy, substance misuse, drug abuse during pregnancy, drug treatment, substance abuse, illegal drugs. Results: There is a general consensus among scientists that drug abuse during pregnancy can cause placental abruption, miscarriage, preterm birth, low birth weight and congenital malformation. Drug dependent pregnant women need to be treated with support, without condemnation and ensuring all necessary information about procedures during pregnancy. Collaboration between gynecologist, midwife, psychiatrist, social worker, psychologist, therapist and social work centre is very important and so is their attitude. Discussion and conclusion: Pregnant women who use illicit drugs are at risk for their baby to sustain serious injuries that can lead to death. Early detection is very important. Interdisciplinary approach must be used in prevention and detoxication treatment. The role of midwife is mostly mental support, informing, advising, health-educational work and promoting health to reduce cosequences of drug abuse.