RT Book, Section A1 Kee Fung, Karen Fung A2 Posner, Glenn D. A2 Dy, Jessica A2 Black, Amanda A2 Jones, Griffith D. SR Print(0) ID 1106378081 T1 Multiple Pregnancy T2 Oxorn-Foote Human Labor & Birth, 6e YR 2015 FD 2015 PB McGraw-Hill Medical PP New York, NY SN 9780071740289 LK obgyn.mhmedical.com/content.aspx?aid=1106378081 RD 2024/04/24 AB In 1895, Hellin described a mathematically simple rule for estimation of the rates of twinning and conception of higher order multiples in the general population. This rule, which has been widely cited and accepted, proposes the following rates of multiple pregnancy: