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
- Imaizumi Y. A comparative study of zygotic twinning and triplet rates in eight countries, 1972-1999. J Biosoc Sci. 2003;35(2):287-302.
- 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
- National Oceanic and Atmospheric Administration. “NWS Lightning Safety: Understanding Lightning Introduction.” Website: http://www.lightningsafety.noaa.gov/odds.htm