What hormone is essential for sustaining pregnancy and is produced in significant amounts during the luteal phase?

Progesterone is the primary hormone critical for sustaining pregnancy, particularly during the luteal phase of the menstrual cycle. After ovulation, the corpus luteum forms and secretes significant amounts of progesterone. This hormone plays a fundamental role in preparing the endometrial lining for potential implantation of a fertilized egg.

Progesterone helps maintain the thickened endometrium and creates a favorable environment for embryo development while also suppressing uterine contractions that could disrupt pregnancy. It also reduces the production of other hormones, which could interfere with pregnancy maintenance.

While estrogen is also present and plays a role in the menstrual cycle and pregnancy, its primary role is not to sustain pregnancy but to support earlier stages, such as preparing the endometrium for implantation and regulating the menstrual cycle. Follistatin and testosterone do not have direct roles in maintaining pregnancy and are not produced in significant amounts during the luteal phase. Thus, the focus on progesterone as the essential hormone in this context is accurate.