External Os

Frequency

Fertility rate

Duckbill

20.6%^a (7/34)

85.7%^x (6/7)

Slit

8.8%^b (3/34)

33.3%^y (1/3)

Rose

29.4%^a,c,e (10/34)

80.0%^z,x (8/10)

Papilla

23.5%^a,d,e (6/34)

100.0%^w,z,v (6/8)

Flap

17.6%^a,b,f (5/34)

88.9%^v,x,y,w (5/6)