Blighted ovum

Anembryonic gestation
Other namesAnembryonic gestation, anembryonic pregnancy
Transvaginal ultrasonography showing a gestational sac with a diameter of 28 mm, corresponding to a gestational age of approximately 7 weeks and 5 days. It contains a yolk sac (protruding from its lower part) but no embryo, even after scanning across all planes of the gestational sac, thus being diagnostic of an anembryonic gestation.
SpecialtyObstetrics

A blighted ovum is a pregnancy in which the embryo never develops or develops and is reabsorbed.[1] In a normal pregnancy, an embryo would be visible on an ultrasound by six weeks after the woman's last menstrual period.[2] Anembryonic gestation is one of the causes of miscarriage of a pregnancy and accounts for roughly half of first-trimester miscarriages.[3][4][5][6] A blighted ovum cannot result in a viable pregnancy.[2][7]

A blighted ovum or anembryonic gestation is characterized by a normal-appearing gestational sac, but the absence of an embryo.[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.[2][7] Because of the presence of hCG, an ultrasound is typically necessary to diagnose an anembryonic pregnancy.[3] 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.[8] Generally, a transvaginal ultrasound is used to investigate a suspected case of blighted ovum.[2][7] 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.[9] A transabdominal ultrasound can be used to diagnose anembryonic pregnancy if a gestational sac can be identified, but is empty.[3] An anembryonic pregnancy is never viable, as in viable pregnancy the embryo must form with the gestational sac.[2]

  1. ^ Kim Mackenzie-Morris. "What is a blighted ovum?". Babycentre.co.uk. Retrieved 19 December 2013.
  2. ^ a b c d e f "Blighted Ovum (Anembryonic Pregnancy): Causes & Symptoms". Cleveland Clinic. Retrieved 2024-04-08.
  3. ^ a b c Stuart, Annie. "Blighted Ovum: Causes, Symptoms, and More". WebMD. Retrieved 2024-04-08.
  4. ^ "Blighted Ovum: Symptoms, Causes and Prevention". American Pregnancy Association. 2012-04-26. Retrieved 2017-09-09.
  5. ^ "Blighted ovum: What causes it?". Mayo Clinic. Retrieved 2017-09-09.
  6. ^ Hoffman, Barbara (2012). Williams gynecology. New York: McGraw-Hill Medical. p. 171. ISBN 9780071716727.
  7. ^ a b c "What is a blighted ovum?". BabyCenter. Retrieved 2024-04-08.
  8. ^ "Ultrasound In Pregnancy: What To Expect, Purpose & Results". Cleveland Clinic. Retrieved 2024-04-08.
  9. ^ Campion, Edward W.; Doubilet, Peter M.; Benson, Carol B.; Bourne, Tom; Blaivas, Michael (10 October 2013). "Diagnostic Criteria for Nonviable Pregnancy Early in the First Trimester" (PDF). New England Journal of Medicine. 369 (15): 1443–1451. doi:10.1056/NEJMra1302417. PMID 24106937.