Hormone for Uterine Mucosa Preparation for Implantation

The hormone responsible for preparation of uterine mucosa for implantation is:

Correct Answer: Progesterone

Progesterone is the hormone responsible for preparing the uterine mucosa (endometrium) for implantation of the embryo. It transforms the proliferative endometrium (built up by estrogen) into a secretory state, rich in glycogen and nutrients necessary for embryo nourishment.

Role of Progesterone in Reproduction

• Uterine preparation for implantation: Stimulates endometrial glands to secrete 'uterine milk' (histotrophe) for early embryo nutrition. ✔
• Maintenance of pregnancy: Maintains uterine quiescence (prevents contractions) throughout gestation.
• Suppresses further follicular development: Negative feedback on GnRH/LH — prevents new estrus cycles during pregnancy.
• Cervical mucus: Causes thick, tenacious mucus plug (closes cervix during pregnancy).

Estrogen vs Progesterone in Uterus

• Estrogen: Proliferative phase — endometrial growth, increased vascularity, duct growth in mammary gland.
• Progesterone: Secretory phase — glandular development, implantation preparation, alveolar growth in mammary gland. ✔