Morphometry of human ovaries in normal and growth-restricted fetuses

According to the fetal origins hypothesis, normal growth and development of abdominal organs is disturbed by intra-uterine growth restriction, leading to diseases later in life. The aims of this study were to investigate the effect of growth restriction on the ovaries of human fetuses and to investi gate the dynamics of follicular growth in normal fetuses. We selected 21 no rmal female fetuses (controls) and seven severely intra-uterine growth-rest ricted female fetuses (IUGR cases) from all autopsy records over a 10-year period. Ovarian volume was calculated and from histological sections the vo lume-percentage of follicles in the ovarian cortex, the maximum diameters o f individual follicles and the distribution of the follicle classes and oog onia were determined. The volume of the ovaries increased significantly fro m 0.10 to 0.36 cm(3) in the second half of gestation. The mean volume-perce ntage of ovarian follicles and the mean follicle diameter significantly inc reased with 0.48% and 0.52 mum per week, respectively. Class B/C (intermedi ary) follicles (72%) were predominantly present. Class B (primordial) folli cles decreased from over 20% to less than 10% and class C (primary) increas ed from 6 to 19%. Class A (oogonia) were frequently present before 30 gesta tional weeks, but were rare after that age. For all studied parameters we d id not find differences between IUGR cases and controls. Intra-uterine grow th restriction does not seem to disturb ovarian development in the human fe tus. In the second half of gestation the follicle pool increases by the gro wth of individual follicles, the transition of follicle to larger classes, and probably by increasing follicle numbers. As most follicles at term were class B/C and C, follicles up to class C are probably part of the resting stock. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.