and fetal anomalies increased 2.5-fold in comparison
with normally positioned placentas (5). Practically,
cesarean section is necessary in all women
with PP. Because of the poorly contractile nature
of the lower uterine segment, there may be uncontrollable
postpartum bleeding (6). Placental bed
biopsies at cesarean delivery in women with PP
showed that there were increments of myometrial
spiral arterioles with trophoblastic giant-cell infiltration
(7).
In recent years, microscopic measurements have
been increasingly used both in biological researches
and treatments. During the last two decades,
stereology has been considerably improved,
so that it is the first choice for obtaining threedimensional
data from two-dimensional profiles.
The modern stereology by efficient and designbased
methods permits the quantitative description
of morphology. Applications to placentas in
normal and abnormal pregnancies have proved of
great value for challenging earlier misconceptions
and interpretation of the growth, morphogenesis,
adaptation and functioning at the whole-organ
level (8).
In histological methods, we are always faced
with two-dimensional sections or their microscopic
images. Stereology, based on mathematics and
statistics, makes it possible to estimate threedimensional
data from two-dimensional profiles
of an object (9). In histology, it helps in measurement
of parameters including number, size, surface
area and volume by two-dimensional tissue
sections (10). As an advantage, it provides the
opportunity of generalizing data to entire structure,
by proper and systematic sampling of the
sections. There is no precise data concerning
structural changes of placenta in PP. In the present
study, the stereological changes of placenta in PP
patients in comparison with healthy controls were
investigated.