Blighted ovum

Template:Infobox medical condition (new) A blighted ovum is a pregnancy in which the embryo is reabsorbed or never develops at all.<ref name="babycenter blighted ovum">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> In a normal pregnancy, an embryo would be visible on an ultrasound by six weeks after the woman's last menstrual period.<ref name=":2" /> Anembryonic gestation is one of the causes of miscarriage of a pregnancy and accounts for roughly half of first-trimester miscarriages.<ref name=":1">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref>Template:Cite news</ref><ref>Template:Cite book</ref> A blighted ovum cannot result in a viable pregnancy.<ref name=":2" /><ref name=":3" />

A blighted ovum or anembryonic gestation is characterized by a normal-appearing gestational sac, but the absence of an embryo.<ref name=":2" /> It likely occurs as a result of early embryonic death with continued development of the trophoblast. When small, the sac cannot be distinguished from the early normal pregnancy, as there may be a yolk sac, though a fetal pole is not seen. In anembryonic pregnancy, levels of the pregnancy hormone human chorionic gonadotropin (hCG) typically rise for a time, which can cause positive pregnancy test results and pregnancy symptoms such as tender breasts.<ref name=":2">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref name=":3">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Because of the presence of hCG, an ultrasound is typically necessary to diagnose an anembryonic pregnancy.<ref name=":1" /> For diagnosis, the sac must be of sufficient size that the absence of normal embryonic elements is established. The criteria depends on the type of ultrasound exam performed. A transvaginal ultrasound provides a better view of early pregnancy than a transabdominal ultrasound.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Generally, a transvaginal ultrasound is used to investigate a suspected case of blighted ovum.<ref name=":2" /><ref name=":3" /> A pregnancy is anembryonic if a transvaginal ultrasound reveals a sac with a mean gestational sac diameter (MGD) greater than 25 mm and no yolk sac, or an MGD >25 mm with no embryo.<ref name=":0">Template:Cite journal</ref> A transabdominal ultrasound can be used to diagnose anembryonic pregnancy if a gestational sac can be identified, but is empty.<ref name=":1" /> An anembryonic pregnancy is never viable, as in viable pregnancy the embryo must form with the gestational sac.<ref name=":2" />

See also

• Ovum
• Products of conception

External links

• Blighted Ovum on WebMD
• Anembryonic pregnancy on Radiopaedia.org
• Template:Cite journal
• Facts Are Important: Understanding and Navigating Viability on ACOG