Pregnancy Viability: Age of Viablility & Influencing Factors

Fetal viability refers to the point during pregnancy when a fetus (baby) has a reasonable chance of surviving outside the womb. This crucial milestone typically occurs near the end of the second trimester.

High Risk and High Care babies born before the third trimester are extremely underdeveloped and require immediate, life-saving interventions after delivery. These fragile babies often need specialized treatment in a high-level Neonatal Intensive Care Unit (NICU), where they receive advanced care to support their development. Despite advancements in care and technology, babies born less than 28 weeks may experience a range of complications, both in the short and long term.

The chance of survival for very premature babies has increased dramatically over the years, thanks to advancements in neonatal care in Canada. Although the risks are still high, the odds of survival improve significantly at around 24 weeks gestation. Here's a look at survival rates by gestational age:

• 26 weeks: At the final week of the second trimester, a baby has a strong chance of survival, with survival rates from 80 to 89 percent.

• 25 weeks: Babies born at 25 weeks have a 75 to 85 percent survival rate.

• 24 weeks: At this stage, some studies suggest survival could be as high as 64 to 75 percent with optimal care which in Canada is the standard of care for these babies.

• 23 weeks: The odds for babies born at this gestational age is 34 to 49 percent.

• 22 weeks: Before 23 weeks, survival is typically around 10 to 25 percent.

Data Source: http://www.canadianneonatalnetwork.org/portal/Portals/0/Annual%20Reports/2023%20CNN%20Annual%20Report.pdf

While these statistics highlight the severity of preterm births, it's important to note that ongoing medical innovations are improving survival rates and long-term outcomes. With high-level NICU care, many premature babies now survive at gestational ages that were once deemed non-viable.

Understanding fetal viability and the importance of gestational age can help families navigate the complexities of preterm birth and make informed decisions about care options.