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Survival of "pre-viable" infants in the United States
Hamisu M Salihu1, Donath Emusu, Zakari Y Aliyu
1Department of Maternal and Child Health, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA. hsalihu@uab.edu
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.
Design, Setting And Participants:
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.
Main Outcomes:
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".
