Editing Human chorionic gonadotropin (section)

=== Associations with pathologies ===
Gestational trophoblastic disease like [[hydatidiform mole]]s ("molar pregnancy") or choriocarcinoma may produce high levels of βhCG due to the presence of [[syncytiotrophoblasts]], part of the villi that make up the placenta, and despite the absence of an embryo. This, as well as several other conditions, can lead to elevated hCG readings in the absence of pregnancy.{{cn|date=September 2023}}

hCG levels are also a component of the [[triple test]], a screening test for certain fetal chromosomal abnormalities/birth defects. High hCG levels in the maternal serum could suggest [[Down syndrome]], potentially due to continued hCG production by the placenta beyond the first trimester.<ref>{{cite journal | vauthors = Jiang H, Lin Y, He X | title = Association Analysis between Maternal Serum Biomarkers and Fetal Congenital Heart Disease | journal = The Heart Surgery Forum | volume = 26 | issue = 5 | pages = E552–E559 | date = October 2023 | pmid = 37920073 | doi = 10.59958/hsf.6703 | doi-access = free }}</ref>

A study of 32 normal pregnancies came to the result that a [[gestational sac]] of 1–3&nbsp;mm was detected at a mean hCG level of 1150 IU/L (range 800–1500), a [[yolk sac]] was detected at a mean level of 6000 IU/L (range 4500–7500) and [[fetal heartbeat]] was visible at a mean hCG level of 10,000 IU/L (range 8650–12,200).<ref>{{cite journal | vauthors = Giacomello F, Magliocchetti P, Loyola G, Giovarruscio M | title = [Serum beta hCG levels and transvaginal echography in the early phases of pregnancy] | language = it | journal = Minerva Ginecologica | volume = 45 | issue = 7–8 | pages = 333–337 | year = 1993 | pmid = 8414139 }}</ref>