Which hormone is primarily produced by the placenta to maintain pregnancy?

The hormone primarily produced by the placenta to maintain pregnancy is human chorionic gonadotropin (hCG). This hormone is crucial in the early stages of pregnancy as it helps to sustain the corpus luteum, which in turn continues producing progesterone. Progesterone is important for maintaining the uterine lining and supporting embryo implantation and development.

hCG is known for its role in signaling the body to halt the menstrual cycle and encouraging the production of other hormones necessary for pregnancy. It is also the hormone detected in pregnancy tests.

While progesterone and estrogen are essential for maintaining pregnancy, especially later on, hCG is the key hormone produced by the placenta in the initial stages, making it vital for the early maintenance of the pregnancy. Luteinizing hormone, on the other hand, is primarily involved in the menstrual cycle and ovulation rather than sustaining pregnancy.