Viability week refers to the stage of pregnancy when a fetus has a reasonable chance of surviving outside the uterus if born prematurely, usually with medical support. This period is generally considered to begin around 23 to 24 weeks of gestation. Key points about viability week:
- Medical viability is typically recognized between 23 and 24 weeks of gestation. At this point, the fetus's lungs and other vital organs have developed enough to potentially sustain life outside the womb, although survival rates and risks of severe impairment vary
- At 24 weeks , the chance of survival improves significantly, with survival rates ranging from about 42% to 59%, and some studies showing up to 68% survival with intensive care
- Survival rates increase with each additional week of gestation. For example, at 25 weeks, survival chances rise to approximately 67% to 76%, and by 26 weeks, the odds of survival reach 86% to 89%
- Before 23 weeks, the likelihood of survival is very low (around 5-6% at 22 weeks), and most babies born before viability cannot survive due to underdeveloped organs
- The exact definition of viability can vary by country, medical facility, and available technology. In some places, viability might be considered as late as 28 weeks, while in others, advances in neonatal care have pushed viability earlier
- Viability is not a fixed point but a range influenced by gestational age, birth weight, medical care quality, and individual fetal development
In summary, "viability week" is generally around 24 weeks of pregnancy, marking the earliest stage at which a fetus has a meaningful chance of survival outside the womb with medical intervention, though outcomes improve with further gestational age. This concept is important medically and legally, influencing decisions about neonatal care and abortion regulations
