What is the viable age of a fetus in terms of gestational age (GA) for a pregnant individual in this location?

Fetal Viability by Gestational Age

The periviable period is defined as 20 0/7 to 25 6/7 weeks of gestation, with meaningful survival beginning at approximately 23 weeks, though outcomes remain poor with high morbidity until 24-25 weeks. 1

Gestational Age-Specific Viability Thresholds

Before 23 Weeks (Previable)

• Delivery before 23 0/7 weeks typically results in neonatal death with only 5-6% survival, and among rare survivors, significant morbidity is universal at 98-100%. 1, 2
• These infants are generally not candidates for life-sustaining interventions, as the fetus would not survive outside the uterus even with aggressive neonatal intensive care. 1

23 Weeks (Early Periviable)

• Survival rates range from 23-27% at 23 weeks of gestation. 1, 2
• Among survivors, 40% have moderate-to-severe neurodevelopmental impairment. 2
• Wide variation exists between institutions regarding initiation of resuscitation and active treatment at this gestational age, which explains differences in survival outcomes. 1, 2

24 Weeks (Mid-Periviable)

• Survival rates increase substantially to 42-59% at 24 weeks of gestation. 1, 2
• Moderate-to-severe neurodevelopmental impairment occurs in 28% of survivors. 2
• Practices and outcomes become more consistent across tertiary care institutions at this gestational age compared to earlier weeks. 1

25 Weeks (Late Periviable)

• Survival rates improve to 67-76% at 25 weeks of gestation. 1, 2
• Moderate-to-severe neurodevelopmental impairment decreases to 24% of survivors. 2
• Most infants at this gestational age will survive, and most survivors will not be severely disabled. 1

Critical Factors Affecting Viability Beyond Gestational Age

Viability is not determined by gestational age alone but represents a physiological continuum impacted by multiple clinical factors. 1

Key modifying factors include:

• Estimated fetal weight and growth status significantly impact survival potential. 2
• Multiple gestations alter viability thresholds. 2
• Fetal genetic diseases and congenital anomalies substantially reduce survival likelihood. 1, 2
• Institutional practices regarding resuscitation, particularly at 22-23 weeks, explain between-hospital differences in survival and survival without impairment. 1, 2
• Administration of antenatal corticosteroids improves outcomes. 2
• Location of delivery, with tertiary care centers achieving better outcomes than community hospitals. 2

Clinical Implications for Decision-Making

Counseling must acknowledge that the periviable period (20 0/7 to 25 6/7 weeks) represents a zone where outcomes range from certain or near-certain death to likely survival with high likelihood of serious morbidities. 1

Common Pitfalls to Avoid

• Do not assume uniform outcomes across all 23-week or 24-week deliveries—outcomes at the extremes of each gestational week may be closer to those of the adjacent week. 2
• Recognize that institutional variation in resuscitation practices, particularly at 22-23 weeks, creates significant outcome differences that should be discussed with families based on local data. 1, 2
• Understand that expectant management of previable PPROM provides no direct medical benefit to the pregnant individual and carries substantial maternal risks including sepsis, with maternal mortality rates of 45 per 100,000 in this setting. 1

Historical Context

From the 1950s through 1980, newborn death was virtually assured with delivery at or before 24 weeks of gestation, but there has been progressive improvement in survival rates over the past three decades. 1, 2