gynecology and obstetrics medical project, gynecology journal, obstetrics, gynecologic oncology, reproductive medicine, gynecological endoscopy, ultrasonography, gynecology articles

Ginekologia i Poloznictwo
ISSN 1896-3315 e-ISSN 1898-0759

Mechanisms of twin dizygotic pregnancies formation. Prevalence and predisposing factors



The first universal birth registry of children was initiated in Nordic countries in the 17th century. In Sweden and Finland it was officially introduced in 1749. Since then, the prevalence of twin pregnancies has been estimated in these countries. It turned out that the proportion of twin pregnancies was relatively constant until the end of the 19th century. Since 1900, the decreasing occurrence of twin pregnancies has been recorded in most European countries and the US. This trend remained present until the end of the 1970s, when a reverse tendency was observed and lasts until today