Human chorionic gonadotropin (hCG) is uniquely synthesized by the human placenta to maintain early pregnancy by sustaining the corpus luteum, unlike other mammals where similar hormones originate elsewhere.
Primates including humans produce placental chorionic gonadotropin; other species use different mechanisms.

Correct Answer

(D) Human​

Option Analysis

• (A) Cattle: Bovine placenta produces placental lactogen (bPL) but not chorionic gonadotropin; pregnancy maintenance relies on interferon-tau (IFNT) from conceptus trophectoderm, not hCG.​

• (B) Pigs: Porcine placenta lacks significant gonadotropin production; pregnancy recognition uses estrogen signaling from pig conceptus to extend luteal function, without hCG equivalent.​

• (C) Mice: Rodent placentas produce placental lactogens (PLs) but no hCG; mice maintain pregnancy via progesterone from corpora lutea without chorionic gonadotropin involvement.​

• (D) Human: Human syncytiotrophoblast produces hCG from week 1 post-implantation, peaking at 8-10 weeks to rescue corpus luteum progesterone production until placental shift.

Placental Hormone Evolution

hCG evolved in primates for maternal recognition; equine CG (eCG) exists but cattle/pigs/mice use species-specific signals. Human pregnancy tests detect urinary hCG.​

Chorionic Gonadotropin Placenta Pregnancy: Human Specificity

Chorionic gonadotropin placenta pregnancy maintenance defines human reproduction. hCG from syncytiotrophoblast sustains corpus luteum progesterone for first trimester, preventing menstruation.​

Species Comparison

Chorionic gonadotropin placenta pregnancy role critical for GATE Life Sciences reproductive endocrinology. hCG double-subunit glycoprotein detectable in blood/urine by week 3.​

GATE Prep Insights

• Peak: 60-100K mIU/mL at 8-10 weeks.

• Function: LH-like (LH/CG receptor).

• Test focus: Human uniqueness vs. domestic mammals.​