Survival of "pre-viable" infants in the United States.
OBJECTIVE
We investigated temporal trend in survival of pre-viable (200-499 g) fetuses over the previous decade, and estimated future survival rates based on previous and current survival thresholds.


METHODS
This was a retrospective cohort study on live-born pre-viable fetuses (200-499 g) in the United States comparing two period cohorts; 1985-1988 versus 1995-1999. We computed survival of pre-viable babies (who were still alive at 24 hours) during the two periods and based on these results, we estimated future survival rates for the coming decades.


RESULTS
Survival beyond the neonatal period.


RESULTS
About 35 million live births were analyzed for the two periods. In the first period (1985-1988), 927 live births among pre-viable fetuses were recorded while in the second period (1995-1999) 2585 were counted, equivalent to a birth rate of 60.6 and 131.9 per million live births respectively. This corresponds to an increase of more than 100% across the decade (p for trend < 0.0001). Survival improved by about 50% across the period, from 12.0% to 17.4% (p < 0.0001). Based on these results, the survival rate among pre-viable fetuses will be expected to rise to about 24.0% within the next 6 years (2010).


CONCLUSIONS
Survival among pre-viable fetuses is increasing in the United States. This raises ethical, legal and medical issues concerning the defined viability status of these babies, which is currently described as "non-viable".
Salihu
Hamisu M
HM
Department of Maternal and Child Health, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA. hsalihu@uab.edu
Emusu
Donath
D
Aliyu
Zakari Y
ZY
Kirby
Russell S
RS
Alexander
Greg R
GR
D001719:Birth Certificates; D001723:Birth Rate / Q000639:trends*; D015331:Cohort Studies; D016208:Databases, Factual; D005260:Female; D006801:Humans; D007226:Infant Mortality / Q000639:trends*; D007231:Infant, Newborn; D007234:Infant, Premature; D019102:Infant, Very Low Birth Weight; D008297:Male; D047928:Premature Birth / Q000401:mortality*; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D017678:Sex Distribution; D016019:Survival Analysis; D015996:Survival Rate; D014481:United States / Q000453:epidemiology