Hormones secreted by the placenta to maintain pregnancy are

The hormones secreted by the placenta to maintain pregnancy are hCG, hPL, progestogens, and estrogens. The placenta is the intimate connection between the fetus and the uterine wall of the mother to exchange the materials. It has endocrine function and secretes the following hormones:
(i) Human Chorionic Gonadotropins (hCG) — It stimulates and maintains the corpus luteum to secrete progesterone until the end of pregnancy.
(ii) Human Placental Lactogen (hPL) — It is also known as Human Chorionic Somatomammotropin (HCS), which stimulates the growth of mammary glands during pregnancy.
(iii) Progesterone and estrogens support fetal growth, maintain pregnancy, inhibit uterine contractions, etc.
On the other hand, the sources of other hormones are as follows:
Oxytocin: Secreted by the posterior lobe of the pituitary gland during fetal ejection reflex.
Glucocorticoid: Secreted by adrenal gland of the fetus to induce fetal ejection reflex.
Relaxin: Secreted by corpus luteum to increase the flexibility of pubic symphysis.
Prolactin Secreted by the anterior lobe of the pituitary helps in the secretion of milk.