|  | | The nulliparous and parous cervix |    | 
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 The nulliparous cervix has a smooth, round external os. The parous cervical os is uneven and wide, often described as having a “fish mouth” appearance. The parous cervix is more bulky than the nulliparous cervix.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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