Bacteria, fungi, viruses and parasites are the most common causes of infection in pregnancy that may subsequently lead to miscarriage, premature birth and low birth weight in the neonate. Due to changes in the immune system, as well as different biological flora in the birth canal, pregnancy favours the development of infections. Intrauterine and intrapartum infections manifest in the first 72 hours of birth, whereas after this period we are dealing with infections in the neonatal period. The child can be infected during migration process through the birth canal, which can possibly endanger child’s health. The analysis of the urine, i.e. urine culture is commonly used to establish bladder infection in pregnant women. The risk is highest between 6 and 24 weeks of pregnancy. The bacteria from the gastrointestinal tract arrive through the urethra into the urinary tract, where they start to propagate. The incidence is more common in women due to the short urethra, as well as its anatomical position (the proximity of the vagina and the anus), which in turn increases the risk of developing urinary tract infections. Under the influence of hormones that are secreted during pregnancy, urethra also becomes more vulnerable to the penetration of bacteria. Furthermore, genital infections are seen due to anatomical structures, changes in pH of the vagina and promiscuity, but the most common reason is perturbed vaginal flora. Certain infections can be dangerous when occurring outside pregnancy, but in pregnancy they are especially harmful as they can cause various complications and endanger the foetus. Out of fear from the possible adverse influence of treatment on the foetus, pregnant women often refuse antibiotic treatment of urogenital infections and sexually transmitted diseases. They are not aware that the consequences of lack or inappropriate treatment can be much more dangerous for the unborn child than the potential damage due to drugs used in the therapy. It is thus of utmost importance to start the treatment early, and to conduct complete microbiological assessment prior to pregnancy in order to institute adequate treatment timely, if necessary.