Number of ovarian follicles in human fetuses with the 45,x karyotype Karine Reynaud, Ph.D., Rita Cortvrindt, M.Sc., Franciska Verlinde, M.D., Jean De Schepper, M.D., Ph.D., Claire Bourgain, M.D., Ph.D., Johan Smitz, M.D., Ph.D.  Fertility and Sterility  Volume 81, Issue 4, Pages 1112-1119 (April 2004) DOI: 10.1016/j.fertnstert.2003.12.011

FIGURE 1 (A) Ovarian section of a control ovary at 18 weeks' gestation. Numerous oogonia are visible, organized in cordlike structures within mesenchymal cells. (B, B′) Sections through a control fetal ovary at 22 weeks. Primordial follicles are present, surrounded by flattened pregranulosa cells. (C, C′) Fetal ovary at 25 weeks' gestation, showing growing follicles with cuboidal granulosa cells. (D, D′) Fetal ovary at 26.5 weeks' gestation. Numerous primordial follicles can be observed (D), and large growing preantral and antral (D′) follicles are present. (E, E′) Fetal ovary (28 weeks' gestation) showing primordial follicles (E) and growing follicles. Theca cells are well organized around the basal membrane (E′). Presence of primordial and growing follicles was also observed on sections at later gestational stages: 30 weeks' (F, F′), 34 weeks' (G, G′), and 35 weeks' (H, H′) gestation. Scale bars = 20 μm (H, H′), 50 μm (H, H′), 100 μm (B, C, D, E, E′, F, G′), or 200 μm (D′, F′, G, H). Reynaud. 45,X and 46,XX human fetal ovaries. Fertil Steril 2004. Fertility and Sterility 2004 81, 1112-1119DOI: (10.1016/j.fertnstert.2003.12.011)

FIGURE 2 Ovarian section of Turner ovaries at different gestational stages. (A, A′) Fetal Turner ovary at 17 weeks' gestation, with numerous small oogonia, histologically preserved. Large oogonia (white arrow) are degenerated, with a contracted nucleus and a thin layer of cytoplasm bordering the inner side of the cell. Parenchymal cells (ovoid nucleus) are present. (B) Fetal ovary at 18 weeks' gestation. Germ cells are rarely observed. (C) Fetal ovary (20 weeks' gestation) with numerous germ cells but no primordial follicles. (D, D′) Fetal ovary at 23 weeks' gestation. Some oogonia with histologically preserved nucleus are visible. No primordial follicles can be detected. (E) Fetal ovary at 25 weeks' gestation revealing a complete absence of germ cells or primordial follicles. (F, F′) Fetal ovary at 25 weeks' gestation containing few germ cells (white arrows) but no primordial follicles. (G, G′) Fetal ovary at 27 weeks' gestation containing a lot of stroma and few small oogonia (white arrow) but no primordial follicles. (H, H′) Fetal ovary at 31 weeks' gestation. Numerous oogonia are present, but primordial follicles are totally absent. Fibroblasts and pregranulosa cells (with numerous mitosis) were clearly visible. (I) Fetal ovary at 33 weeks' gestation showing numerous oogonia (not histologically preserved). (J, J′) Fetal ovary at 37 weeks' gestation showing few oogonia (white arrow) and pregranulosa cells (proliferating). Scale bars = 45 μm (A′, B, D, D′, F, F′, G′, H′, J, J′) or 90 μm (A, C, E, G, H, I). Reynaud. 45,X and 46,XX human fetal ovaries. Fertil Steril 2004. Fertility and Sterility 2004 81, 1112-1119DOI: (10.1016/j.fertnstert.2003.12.011)

FIGURE 2 Ovarian section of Turner ovaries at different gestational stages. (A, A′) Fetal Turner ovary at 17 weeks' gestation, with numerous small oogonia, histologically preserved. Large oogonia (white arrow) are degenerated, with a contracted nucleus and a thin layer of cytoplasm bordering the inner side of the cell. Parenchymal cells (ovoid nucleus) are present. (B) Fetal ovary at 18 weeks' gestation. Germ cells are rarely observed. (C) Fetal ovary (20 weeks' gestation) with numerous germ cells but no primordial follicles. (D, D′) Fetal ovary at 23 weeks' gestation. Some oogonia with histologically preserved nucleus are visible. No primordial follicles can be detected. (E) Fetal ovary at 25 weeks' gestation revealing a complete absence of germ cells or primordial follicles. (F, F′) Fetal ovary at 25 weeks' gestation containing few germ cells (white arrows) but no primordial follicles. (G, G′) Fetal ovary at 27 weeks' gestation containing a lot of stroma and few small oogonia (white arrow) but no primordial follicles. (H, H′) Fetal ovary at 31 weeks' gestation. Numerous oogonia are present, but primordial follicles are totally absent. Fibroblasts and pregranulosa cells (with numerous mitosis) were clearly visible. (I) Fetal ovary at 33 weeks' gestation showing numerous oogonia (not histologically preserved). (J, J′) Fetal ovary at 37 weeks' gestation showing few oogonia (white arrow) and pregranulosa cells (proliferating). Scale bars = 45 μm (A′, B, D, D′, F, F′, G′, H′, J, J′) or 90 μm (A, C, E, G, H, I). Reynaud. 45,X and 46,XX human fetal ovaries. Fertil Steril 2004. Fertility and Sterility 2004 81, 1112-1119DOI: (10.1016/j.fertnstert.2003.12.011)