Large yolk sac
Citation, DOI, disclosures and article data
At the time the article was created Yuranga Weerakkody had no recorded disclosures.View Yuranga Weerakkody's current disclosures
At the time the article was last revised Jeremy Jones had no recorded disclosures.View Jeremy Jones's current disclosures
A large yolk sac is one measuring >5-6 mm in pregnancies between a gestational age of 5-10 weeks. One study had shown that a yolk sac diameter of >5 mm can be associated with an increased risk of spontaneous miscarriage although few other authors have mentioned the existence of a very large yolk sac (e.g. around 8 mm) in a normal live pregnancy 2.
Abnormally large yolk sac may indicate a poor obstetric outcome and close follow-up with sonography is often recommended for these pregnancies.
- indeterminate abnormal yolk sac abnormality that should not be considered alone for the diagnosis of failed early pregnancy
- follow-up ultrasonography at 7-14 days to assess the pregnancy for viability is generally appropriate
- 1. Sinan Tan. Sonographic Evaluation of the Yolk Sac. JUM. 2012;31 (1): 87-95. JUM (full text)
- 2. Cho FN, Chen SN, Tai MH et-al. The quality and size of yolk sac in early pregnancy loss. Aust N Z J Obstet Gynaecol. 2006;46 (5): 413-8. doi:10.1111/j.1479-828X.2006.00627.x - Pubmed citation
- 3. Cepni I, Bese T, Ocal P et-al. Significance of yolk sac measurements with vaginal sonography in the first trimester in the prediction of pregnancy outcome. Acta Obstet Gynecol Scand. 1998;76 (10): 969-72. Pubmed citation
- 4. Küçük T, Duru NK, Yenen MC et-al. Yolk sac size and shape as predictors of poor pregnancy outcome. J Perinat Med. 1999;27 (4): 316-20. doi:10.1515/JPM.1999.045 - Pubmed citation
- 5. Varelas FK, Prapas NM, Liang RI et-al. Yolk sac size and embryonic heart rate as prognostic factors of first trimester pregnancy outcome. Eur. J. Obstet. Gynecol. Reprod. Biol. 2008;138 (1): 10-3. doi:10.1016/j.ejogrb.2007.06.023 - Pubmed citation