Immunoglobulin G (IgG) level in fetus as fraction of adult IgG level

Range before week 16 of gestation <8%: between weeks 17 and 22 of gestation 10-20%: by 26 weeks of gestation till delivery 100% % of the average normal adult concentration
Organism Human Homo sapiens
Reference Saji F, Samejima Y, Kamiura S, Koyama M. Dynamics of immunoglobulins at the feto-maternal interface. Rev Reprod. 1999 May4(2):81-9 p.81 left column bottom paragraphPubMed ID10357095
Primary Source Gitlin D (1971) Development and metabolism of the immunoglobulins. In Immunologic Incompetence pp 3–13 Eds BM Kagan and ER Stiehm. Year Book Medical Publishers, Chicago
Comments P.81 left column bottom paragraph: "The immunoglobulins in the fetus consist almost totally of maternal IgG and are transferred across the placenta by means of a specific receptor-mediated mechanism. IgG transport from mother to fetus begins at about week 16 of gestation and increases thereafter. Before week 16 of gestation, serum IgG concentrations of the fetus are < 8% of the average normal adult concentration. Between weeks 17 and 22 of gestation, fetal serum IgG concentrations range between approximately 10 and 20% of the adult value, and, after week 22 of gestation increase rapidly, reaching maternal serum IgG concentrations by 26 weeks of gestation and maintaining them until delivery (primary source)."
Entered by Uri M
ID 117055