At approximately day 1

Ovaries move into pelvis.

Reference [PubMed Link]

Pryor JL, Hughes C, Foster W, Hales BF, Robaire B. 2000. Critical windows of exposure for children’s health: the reproductive system in animals and humans. Environ Health Perspect 108 (Suppl 3):491-503.

At approximately day 1

The nipple anlage have formed; there is condensation of the mesenchyme to form the smooth muscle of the nipple. The edge of the breast anlage has begun to from outgrowths.

Duration: 4 weeks

Reference [PubMed Link]

Laurence DJ, Monaghan P, Gusterson, BA. 1991. The development of the normal human breast. Oxford Reviews of Reproductive Biology 13:149-174.

At approximately day 1

Ovarian cortex begins to thicken due to increased mitosis of germ cells and primitive granulosa cells.

Reference [PubMed Link]

Rabinovici J, Jaffe RB. 1990. Development and regulation of growth and differentiated function in human and subhumand primate fetal gonads. Endocrine Reviews 11(4):532-557.

At approximately day 1

Oogenesis: Zygotene stage of meiosis starts (chromosomes line up in homologous pairs) and reaches its peak.

Duration: 1 week

Reference [PubMed Link]

Rabinovici J, Jaffe RB. 1990. Development and regulation of growth and differentiated function in human and subhumand primate fetal gonads. Endocrine Reviews 11(4):532-557.

At approximately day 1

Primordial sex cords have split and fragmented in the basal area of the ovary (medulla).

Reference [PubMed Link]

Satoh M. 1991. Histogenisis and organogenisis of the gonad in human embryos. J. Anat 177:85-107.