The 'Hormone Progesterone' is primarily responsible for maintaining pregnancy. During the menstrual cycle, its levels are highest during the: MCQ with Answer and Explanation

Progesterone is the primary hormone of the luteal phase (also called the secretory phase) of the menstrual cycle. After ovulation, the ruptured Graafian follicle transforms into the corpus luteum, which secretes large amounts of progesterone. Progesterone prepares and maintains the uterine endometrium (thickening it, increasing blood supply, and stimulating glandular secretion) for the potential implantation of a fertilized egg. If pregnancy does not occur, the corpus luteum degenerates, progesterone levels drop, and menstruation begins.