In cases of ectopic pregnancy, how does hCG behave compared to normal pregnancy?

In cases of ectopic pregnancy, human chorionic gonadotropin (hCG) behaves differently compared to a normal intrauterine pregnancy. In a normal pregnancy, hCG typically rises predictably and doubles approximately every 48 to 72 hours during the early weeks. This predictable rise is a key indicator of a healthy, developing pregnancy.

However, in an ectopic pregnancy, the pattern of hCG rise is often abnormal. Instead of doubling at the expected rate, the levels may rise inconsistently or even plateau and decline. This irregularity occurs because the ectopic tissue is not supported by the normal physiological environment of the uterus, leading to suboptimal production of hCG. Therefore, hCG in ectopic pregnancies often fails to show the characteristic doubling that is expected in viable intrauterine pregnancies. This abnormal behavior of hCG serves as a significant diagnostic indicator for healthcare providers suspecting an ectopic pregnancy.