**Question:** Maximum level of beta HCG is seen at-

A. 16-18 weeks of gestation
B. 24-28 weeks of gestation
C. 34-36 weeks of gestation
D. 40 weeks of gestation

**Core Concept:** Human Chorionic Gonadotropin (hCG) is a glycoprotein hormone produced by the syncytiotrophoblast cells in the placenta following implantation of the fertilized ovum in the uterine wall during pregnancy. Beta-hCG is the beta subunit of hCG and is more specific for pregnancy confirmation and monitoring.

**Why the Correct Answer is Right:** The maximum level of beta-hCG is seen at around 24-28 weeks of gestation because this is when placental function is at its peak during the second trimester. At this stage, the placenta produces high levels of beta-hCG to ensure optimal fetal growth and development.

**Why Each Wrong Option is Incorrect:**

A. 16-18 weeks of gestation: While beta-hCG levels increase during the first trimester, they peak at the second trimester, not early in the first trimester.

B. 24-28 weeks of gestation: Although beta-hCG levels decrease slightly in the third trimester, they do not reach their maximum at this stage.

C. 34-36 weeks of gestation: Beta-hCG levels generally decrease during the third trimester as gestation nears its end.

D. 40 weeks of gestation: Beta-hCG levels generally decrease during the fourth trimester as gestation advances and the placenta starts producing fewer hormones.

**Clinical Pearl:** Monitoring beta-hCG levels during pregnancy can help identify potential complications such as preterm labor, ectopic pregnancy, or miscarriage. A sudden drop in beta-hCG levels may indicate a biochemical pregnancy or ectopic pregnancy, while a gradual decrease suggests normal pregnancy progression. A beta-hCG level less than 5 mIU/ml at 10 weeks gestation may indicate an ectopic pregnancy. A beta-hCG level less than 5 mIU/ml at 11 weeks gestation may indicate a biochemical pregnancy.

**Why Each Wrong Option is Incorrect:**

A. 10 weeks gestation: This is too early in pregnancy when beta-hCG levels are still rising.

B. 16-20 weeks gestation: This is during the second trimester when beta-hCG levels are generally higher but not yet at their peak.

C. 34-36 weeks gestation: This is during the third trimester when beta-hCG levels generally decrease.

D. 40 weeks gestation: This is during the fourth trimester when beta-hCG levels generally decrease as gestation advances.