Editing Blood type (section)

===Hemolytic disease of the newborn (HDN)===
{{Main|Hemolytic disease of the newborn}}
A [[Pregnancy|pregnant]] woman may carry a [[fetus]] with a blood type which is different from her own. Typically, this is an issue if a RhD negative mother has a child with a RhD positive father, and the fetus ends up being Rh positive.<ref>{{cite web |last1=Freeborn |first1=Donna |title=Hemolytic Disease of the Newborn (HDN) |url=https://www.urmc.rochester.edu/encyclopedia/content.aspx?ContentTypeID=90&ContentID=P02368 |website=University of Rochester Medical Center |access-date=30 November 2020 |archive-date=19 September 2016 |archive-url=https://web.archive.org/web/20160919082228/https://www.urmc.rochester.edu/encyclopedia/content.aspx?ContentTypeID=90&ContentID=P02368 |url-status=live }}</ref> In those cases, the mother can make [[Immunoglobulin G|IgG]] blood group antibodies. This can happen if some of the fetus' blood cells pass into the mother's blood circulation (e.g. a small fetomaternal [[bleeding|hemorrhage]] at the time of childbirth or obstetric intervention), or sometimes after a therapeutic [[blood transfusion]].  This can cause [[hemolytic disease of the newborn]] (HDN) in the current pregnancy and/or subsequent pregnancies.  Sometimes this is lethal for the fetus; in these cases it is called [[hydrops fetalis]].<ref name =Letsky2000>{{cite book |title =Antenatal & neonatal screening |edition = 2nd |chapter = Chapter 12: Rhesus and other haemolytic diseases |author = E.A. Letsky |author2=I. Leck|author3=J.M. Bowman |year = 2000 |publisher = Oxford University Press|isbn=978-0-19-262826-8}}</ref> If a pregnant woman is known to have anti-D antibodies, the RhD blood type of a [[fetus]] can be tested by analysis of fetal DNA in maternal plasma to assess the risk to the fetus of Rh disease.<ref>{{cite journal |vauthors=Daniels G, Finning K, Martin P, Summers J |title=Fetal blood group genotyping: present and future |journal=Annals of the New York Academy of Sciences |volume=1075 |pages=88–95 |date=September 2006 |issue=1 |pmid=17108196 |doi=10.1196/annals.1368.011 |bibcode=2006NYASA1075...88D }}</ref> Cell-free DNA testing can determine the fetal ''RHD'' genotype in a sample of material plasma after 10 weeks of gestation. One of the major advances of twentieth-century medicine was to prevent this disease by stopping the formation of anti-D antibodies by D negative mothers with an injectable medication called [[Rho(D) immune globulin]].<ref>{{cite web|url=https://www.rcog.org.uk/index.asp?PageID=1972 |title=Use of Anti-D Immunoglobulin for Rh Prophylaxis |publisher=[[Royal College of Obstetricians and Gynaecologists]] |date=May 2002 |url-status=dead |archive-url=https://web.archive.org/web/20081230200349/https://www.rcog.org.uk/index.asp?PageID=1972 |archive-date=December 30, 2008 }}</ref><ref>{{cite web |url = https://www.nice.org.uk/guidance/TA41/?c=91520 |title = Pregnancy&nbsp;– routine anti-D prophylaxis for D-negative women |publisher = [[National Institute for Health and Clinical Excellence|NICE]] |date = May 2002 |access-date = 2022-02-11 |archive-date = 2022-02-05 |archive-url = https://web.archive.org/web/20220205182251/https://www.nice.org.uk/guidance/TA41/?c=91520 |url-status = live }}</ref> Antibodies associated with some blood groups can cause severe HDN, others can only cause mild HDN and others are not known to cause HDN.<ref name="Letsky2000"/>