UOTW #19 Answer

Answer: Monoamniotic triplets, 3x “very upset”

This scan demonstrates three intrauterine fetuses sharing the same gestational sac (mono-amniotic), early second trimester.  There is no evidence of free fluid in the pelvis, and all three fetuses have identifiable heart beats.

  • Monozygotic triplets occur at a rate of 22.6 to 82.9 per million births, and monochorionic triplets are the least common.1
  • Although clearly the patient is unlucky with these odds, you can tell your patient that she was far more likely to get struck by lightning (1:12K) or die in a shark attack (1:18K).2,3
  1. Imaizumi Y. A comparative study of zygotic twinning and triplet rates in eight countries, 1972-1999. J Biosoc Sci. 2003;35(2):287-302.
  2. International Business Times. “After Air Algerie AH5017 Incident, A Statistical Look At The Probability And Chances of Dying In A Plane Crash.” Website: http://www.ibtimes.com/after-air-algerie-ah5017-incident-statistical-look-probability-chances-dying-plane-crash-1638206
  3. National Oceanic and Atmospheric Administration.  “NWS Lightning Safety: Understanding Lightning Introduction.” Website: http://www.lightningsafety.noaa.gov/odds.htm

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.