In order to achieve conception male and female sexual cell must enter the froces called fertilization, which implies the merging of male and female pronuclei with emegance of the zigota from which the fetus will eventually develop. The process of fertilization in people is incredibly inefficient, the fekundability of women is estimated at 30%, which meand that 2/3 of women will not be able to achieve pregnancy from the first attemp. Occurrence where we find according to some authors two, according to the other three or more consecutive losses of pregnancy before 20 weeks of gestation we call recurrent spontaneous abortion. Although the definitive guidelines for RSP definition do not exist, we are empirically diagnosing the RSP's after the second consecutive abortion and consequently, we are following the treatment. The etiological factors that cause the occurrence of RSP can be divided into those scientifically proven and those we consider as possible, but due to insufficient number of cases we consider them unproven. In the causes for which there are clear diagnostic and therapeutic guidelines, we classiize antiphospholipid syndrome which may be primary or secondary to other pathological entities such as systematic erythematous lupus, where in both cases there are autoantibodies that attack blood vessel membrane cells with subsequent thromboembolic events. Then, chromosomal aberrings of a single partner focusing on balanced changes that result in unbalanced carotype in the embryo, in which the most common findings are reciprocal and Robertson's translocation, with a much less occurrence of the inversion of chromosomes parts. Uterine anomalies involving as much as 25% of proven etiology can be acquired or congenital. In congenital, we classify the anomalies of the uterus as a consequence of evulution disorders in the Mullerian ducts, in which the remaining septum is most common. Acquired anomalies we can divide according to the occurrence of fibroids, adhesions and polyps where fibroids and polyps are creations with a certain growth potential, while adhesions are the result of tissue damage. Somewhat rarer, but in no way neglitable are endocrinological disorders such as inadequate regulated diabetes mellitus or hypothyroidism that may be present before pregnancy or appear in pregnancy for the first time, and remain undetected. The above causes include only 40% of proven causes, while the remaining 60% are still subject to research. Many other factors such as polystic ovarian disease, obesity, hereditary thrombophilia are in close contact with the RSP, but there are no evidence materials to confirm the scientific significance. Today, more attention is being given to cytogenetic abnormalities that conceal an entire world of molecular mechanisms which remain to be discovered farmore in future.