Which hormone is essential for maintaining pregnancy?

Progesterone is the hormone essential for maintaining pregnancy. Its primary role involves preparing the endometrium, or uterine lining, to support a fertilized egg and to sustain a growing fetus. After ovulation, progesterone is produced by the corpus luteum, and as pregnancy progresses, the placenta also continues to produce it. This hormone helps to inhibit contractions of the uterus, prevents the immune system from rejecting the developing embryo, and prepares the breasts for milk production postpartum.

While estrogen plays a crucial role in various aspects of reproduction, including the regulation of the menstrual cycle and the growth of the uterine lining, it is not specifically responsible for maintaining pregnancy. Norepinephrine is primarily involved in the body's response to stress and does not have a direct role in pregnancy, while testosterone is mainly associated with male reproductive functions and does not play a critical role in sustaining a pregnancy in either gender.