Week 24 (threshold)
- Input
- Parto prematuro extremo
- Expected output
- Viabilidade com suporte intensivo; ~50% de sobrevivência
Complex ethical decisions involve family and medical team.
week 24 fetal viability threshold
Week 24: The Threshold of Fetal Viability
Week 24 represents the threshold from which premature babies have survival chances with intensive neonatal support. This milestone has important ethical, clinical and legal implications.
Why week 24?
- At this point, the lungs begin developing alveoli and producing minimal surfactant, making assisted breathing viable. Survival improves progressively with each additional week.
- Between 24 and 27 weeks, survival rates vary widely — from about 50% at week 24 to over 80% at week 27 — depending on available support.
Viability milestones
Week 37 (full term)
- Input
- Início do termo completo
- Expected output
- Bebê pronto para nascer com baixo risco de complicações por prematuridade
Full term: 37 to 40 weeks and 6 days.
Full tool FAQ
The gestational count starts at the LMP by universal medical convention, because the exact date of ovulation and fertilization is rarely known precisely. This means that in the first two gestational weeks, pregnancy has not yet occurred biologically — ovulation and fertilization typically happen in weeks 2–3.
Frequently asked questions
Does every baby born at week 24 survive?
No. Survival depends on birth weight, the baby's clinical condition and the level of neonatal support available. Population statistics do not apply directly to individual cases.