Growth patterns of human ovarian volume during intrauterine and postnatal organogenesis.
BACKGROUND
Ovarian volumes during pre-pubertal, reproductive or menopausal life in a healthy female have been studied by in vivo and anatomical methods. In contrast, conclusive studies on normal human ovarian volume during intrauterine and postnatal organogenesis, when the folliculogenesis occurs, do not exist.


OBJECTIVE
To assess the growth patterns of ovarian volume during human ovarian definitive histogenesis using morphometric methods.


METHODS
Twenty-five left ovaries removed from fetuses, newborns and children with karyotype 46,XX, ranging from 15 to 74 weeks of development.


METHODS
The ovaries were completely cut obtaining serial sections. Ovarian volume was calculated both with the ellipsoid method, using its length, maximum and minimum diameters, and the Cavalieri quantitative morphometric method. The age-related pattern of ovarian volume was studied using linear regression analyses.


RESULTS
Ovarian volume calculated with the Cavalieri method increased from 16 mm3 at the 15th week of development to over 300 mm3 at the end of the process, with a 20-fold increase compared to the initial volume. Ovarian volume calculated with the ellipsoid method ranged between 25 to over 380 mm3, with a 15-fold increase. On average, ellipsoidal volume over-estimated the true Cavalieri volume (mean difference -14%, S.D. 29, p=0.014, Student's t-test for paired samples). Linear regression curves were developed to predict ovarian volume at any age. Overall, the approximation was better for Cavalieri volume (approximately, 72% of variance explained by the linear regression) than for ellipsoid volume (59% of explained variance).


CONCLUSIONS
During the intrauterine and postnatal organogenesis, the normal growth rate of human ovary was almost linear. The calculation of ovarian volume using Cavalieri method does not depend on assumptions about the organ shape and it appears to be more appropriate.
Sforza
Chiarella
C
Functional Anatomy Research Center (FARC), Dipartimento di Morfologia Umana, Facoltà di Medicina e Chirurgia and Facoltà di Scienze Motorie, Università degli Studi di Milano, via Mangiagalli 31, I-20133 Milan, Italy. farc@unimi.it
Ranzi
Andrea
A
Ferrario
Virgilio F
VF
Forabosco
Antonino
A
D005260:Female; D005865:Gestational Age; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007223:Infant; D007231:Infant, Newborn; D038081:Organogenesis / Q000502:physiology*; D006080:Ovarian Follicle / Q000166:cytology / Q000196:embryology / Q000254:growth & development; D010053:Ovary / Q000166:cytology / Q000196:embryology* / Q000254:growth & development*; D011247:Pregnancy