CBSE · Class 12 · Biology · Human ReproductionList the hormones secreted by the placenta during pregnancy and mention their respective significance.

The placenta acts as a temporary endocrine gland during pregnancy, synthesizing and secreting several essential hormones that are indispensable for maintaining pregnancy and supporting fetal development.

1. Human Chorionic Gonadotropin (hCG): This hormone is secreted early in pregnancy. Its primary significance is to stimulate the corpus luteum to continue producing progesterone, thereby preventing menstruation and maintaining the uterine lining.
2. Human Placental Lactogen (hPL): Secreted by the placenta, hPL plays a key role in regulating maternal metabolism, ensuring adequate supply of glucose and nutrients to the developing fetus, and preparing the mammary glands for lactation.
3. Estrogens and Progesterones: Secreted in large quantities later in pregnancy, these hormones are crucial for the structural maintenance of the endometrium, uterine growth, inhibition of premature uterine contractions, and complete preparation of breasts for milk production.
4. Relaxin: Produced towards the end of pregnancy, this hormone helps relax the pelvic ligaments to facilitate smooth childbirth.