The presence of more than one fetus in the uterus (womb) is called “multiple pregnancy”. As a rule, most often it is twins, and less often triplets, fours, or even more. Multiple pregnancies are initially defined as high-risk pregnancies. These risks can have adverse consequences for both the mother and the fetus. For the mother, multiple pregnancies are associated with the risk of diabetes, anemia, premature birth, urinary tract infection, and other minor complaints. For the fetus, this may be accompanied by increased risks such as congenital abnormalities, lower birth weight, prematurity, and a higher likelihood of needing a neonatal intensive care unit. Besides, with multiple pregnancies occurring in a single placenta (monochorionic pregnancy), there may also be some special risks. For example, twin-to-twin transfusion syndrome, anemia-polycythemia sequence, selective restriction of intrauterine development. Some of them require constant monitoring and evaluation, while others require intrauterine surgery. Cases of pregnancy with triplets or a large number of fetuses, although less common, usually have a higher risk than with twins.