13 March 2016

Keeping it Simple - Survival in trisomy 18




So here you are: your fetus or newborn has a diagnosis of trisomy 18 and you ask, "How long will she live?" Your doctor tells you that it's "rare to make it to birth, but if she does, a few days; some live a few weeks"; your googling tells you that 8% live until a year; and your new online friend from the Facebook trisomy group tells you, "Don't give up hope! My daughter's 14!" (or 18 or 25), and you have no idea what on earth to say when your friends ask, "How serious is it?"


So what do we actually know about survival for children with trisomy 18?


  • 72% of pregnancies are lost between 12 weeks and term.
  • 38% of babies who enter labour alive die during labour if not actively managed.
  • Most babies die within the first two weeks if managed palliatively. Around a third die on their first day of life.
  • Survival to a year without treatment is between 6% and 8% of live births.
  • Active treatment appears to improve survival by around 20%.
  • Total survival to a year with active treatment is likely around 25%.
  • So even with the best treatment, 75% of babies die before one year of age.
  • Being premature is one of the factors that makes your baby much more likely to die. In some studies, no premature babies survive long enough to leave the hospital.
  • Being born later may make your baby more likely to survive, so be wary of early inductions and c-section.
  • Girls are more likely to survive than boys. In a big study in Switzerland, 4% of girls were still alive at age 10, whereas no boys survived beyond 7 months.
  • Some medical complications may make your baby more likely to die, but nobody is sure exactly which ones. In one study, no babies with diaphragmatic hernias survived, but in another, they didn't affect survival rates at all. Most studies report that older children tend to die of heart-related conditions.
  • The oldest T18 survivor was 50 years old. She had full T18.
  • Mosaic T18 is more survivable. 70% live past a year, and many live into adulthood.
  • Children with T18 and children with T13 have similar survival statistics at a year, although T18 babies as a group live longer than T13 babies as a group. Mosaic T13 babies, however, do better than mosaic T18 babies.


Diaphragmatic hernia and 39 weeks...
...so Rumer didn't get to her first birthday.

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