A Gross and Histological Study of Human Foetal Ovary at Different Weeks of Gestation

Abstract

Background:The fetal life is a critical period in female fertility in which the germ cells complete proliferation, initiate meiosis and eventually form the life time reserve of primordial follicles. The age associated alteration in the ovaries being development, differentiation, follicular growth and stroma are indicators of reproductive capability. The present study was planned to study the gross and histological structure of human fetal ovary at different weeks of gestation.Materials and Methods: A total of twenty six human female fetuses of different age from 18 th to 36 th gestational week were used for the present study. The fetuses were dissected and the ovaries were removed along with the uterus. The ovaries separated from uterus, weighed, the length and breadth of the ovaries were measured with graph paper. The ovaries were processed for histological studies by fixing, embedding, section cutting, staining by standard methods. The ovarian sections were observed for lining epithelium, ovagirous cords, cortico-medullary differentiation and different stages of follicles by observing their structural architecture.Results: At the 18 th week of gestation the microscopic structure of fetal ovary showed capsule, numerous ovigerous cords and oogonia. At the 20 th week of gestation presence of primordial follicles were observed. At the 24 th week of gestation cortico-medullary differentiation was started. At the 26 th week of gestation primary follicles were clearly seen and the cortico-medullary differentiation was visible. At the 28 th week of gestation many primordial and primary follicles were seen near cortico-medullary junction. At the 30 th week of gestation cortico-medullary differentiation was clearly visible. At the 32 nd week of gestation the multilayered (secondary) follicles started appearing. At the 34 th week of gestation the antral follicles started appearing. At the 36 th week of gestation few pre-antral and 1 to 2 antral follicles were found at cortico-medullary junction. Conclusion:The present study concludes the presence of capsule at 18 th week, primordial folliclesat 20 th week, at 26 th week primary follicles, at 32 nd week secondary follicles and at 34 th week antral follicles.