OB TRIAD
Abnormal    Placental   Invasion
Accreta:    deeper  layers  decidua basalis
Increta:    myometrium  not complete
Percreta:   uterine serosa  or  bladderPlacenta    accreta (most   common, 80% of  cases)  occurs  when    the villi   invade
the deeper  layers  of  the endometrial decidua basalis but do  not penetrate   the
myometrium.
Placenta    increta (15%    of  cases)  occurs  when    the villi   invade  the
myometrium  but do  not reach   the uterine serosal surface or  the bladder.
Placenta    percreta    (5% of  cases)  occurs  when    the villi   invade  all the way to
the uterine serosa  or  into    the bladder.    
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