Which hormone is crucial for maintaining pregnancy?

Progesterone is the hormone crucial for maintaining pregnancy due to its essential role in preparing the uterus for implantation and sustaining the early stages of gestation. After ovulation, the corpus luteum produces progesterone, which leads to several physiological changes in the uterine lining, making it receptive to a fertilized egg.

Progesterone inhibits uterine contractions, reducing the risk of premature labor, and promotes the growth of the endometrium to support the developing embryo. Additionally, it plays a vital role in the establishment of the placenta, which is critical for nutrient and oxygen exchange between the mother and fetus.

While insulin, cortisol, and estrogen have important roles in the body and can influence various aspects of pregnancy, they do not specifically fulfill the same crucial function in maintaining the pregnancy as progesterone does. For instance, insulin is primarily involved in glucose metabolism and energy supply, cortisol is related to stress responses, and estrogen contributes to the development of female secondary sexual characteristics and regulates the menstrual cycle but is not the primary hormone responsible for sustaining pregnancy.