For a fetus experiencing intrauterine growth restriction (IUGR), what factor is most critical for post-delivery survival?

The factor most critical for post-delivery survival in a fetus experiencing intrauterine growth restriction (IUGR) is gestational age at birth. Infants born at earlier gestational ages face increased risks of complications such as respiratory distress syndrome, infections, and other developmental issues, regardless of their birth weight. While birth weight is significant in assessing the growth and development of the fetus, it is not as crucial as gestational age, which determines the maturity of the organs and systems needed for life outside the womb.

Infants delivered at a lower gestational age, even if they have a higher birth weight, are still at risk for poorer outcomes due to their immaturity. Conversely, infants born closer to term, even with IUGR, generally have a better chance of survival and a lower risk of long-term complications. Therefore, gestational age significantly influences the prognosis.