The increasing incidence of obesity worldwide has made this one of the main problems of Public Health during pregnancy, increasing maternal and perinatal comorbidities and altering the normal course of pregnancy; re-sulting in what it is known as high-risk pregnancy. The aim of this study was to determine the association between the body mass index and the complications that occur during pregnancy. A systematic review has been carried out following the criteria of the PRISMA protocol. The search was carried out in the PubMed, Scopus and Cinahl databases between January and May 2019. Obese or overweight women showed more complications in pregnancy, such as gesta-tional diabetes mellitus, preeclampsia, preterm birth, caesarean section, mac-rosomic children and a higher abortion rate, than pregnant women of normal weight. Health education intervention during pregnancy, improved the physical condition of pregnant women, but did not reduce pregnancy complications. It is concluded that overweight and obesity are associated with significant complications during pregnancy and during childbirth.