This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Diagnosis of Pregnancy, Subject name: Gynaecology & Obstetrics
Corpus luteum in the first 6 weeks of pregnancy is maintained by - 
Select and explain. 
A. BetaHCG, B. Estrogen, C. Progesterone, D. Human placental lactogen
A: BetaHCG
Answer: A: BetaHCG 
Explanation: Ans. is 'a' i.e., Beta HCG Functions of Human Chorionic Gonadotropina) Maintainence of corpus luteum till 6 weeks of pregnancy.b) Stimulation of fetal testicular testosterone secretion which is maximum approximately when hCG levels peak.c) Immunosuppressive activity, inhibits maternal processes of immunorejection of the fetus as a homograft.d) Stimulates maternal thyroid (thyrotropic action).e) Promotes relaxin secretion from corpus luteum.