Kazan medical journalKazan medical journal0368-48142587-9359Eco-Vector6402310.17816/kazmj64023Research ArticleChronobiology of labor activityBayteryakI. К.<p>Department of Obstetrics and Gynecology No. 2</p>info@eco-vector.comKazan State Medical University150519987931931952303202123032021Copyright © 1998, Bayteryak I.К.1998<p>Circadian biologic rhythms are studied and the coefficient of their partici pation in labor is revealed. By means of cosinor analysis of labor histories of 6572 women the polar acrophases of labor activity and their relativity to photoperiods of twentyfour hours in discrete ages are established.</p>Kazan Medical archiveКазанский медицинский архив