Characterization of mothers at risk of delivery at the limit of viability and factors related to infant survival.

OBJECTIVES

To determine the sociodemographic and clinical characteristics of mothers of infants at the limit of viability and to know the perinatal factors associated to infants' survival.

METHOD

Single-center cohort study of mothers and newborns assisted in our tertiary care center (2004-2010). Demographic and perinatal variables were compared between mothers who gave birth  ≤26 weeks GA and the general population. The association between perinatal factors and neonatal survival was studied by Cox regression analysis.

RESULTS

Mothers of newborns  ≤26 weeks (n = 136) had less education and pregnancy control. They had more frequently assisted reproductive technologies (ART) (5.2% versus 2.3%; p< 0.05), multiple gestations (16.6% versus 2.1%; p < 0.05), pregnancy complications and C-section (39.7% versus 13.4%; p  < 0.001). After correcting for confounders, the perinatal factors independently associated with a variation in the risk of mortality were the administration of antenatal steroid [aHR (95%CI): 0.465 (0.254-0.853), p = 0.013], singleton pregnancy [aHR (95%CI): 0.482 (0.279-0.834), p = 0.009], infant's temperature on admission [aHR (95%CI): 0.642 (0.426-0.968), p = 0.035] and CRIB score [aHR (95%CI): 1.151 (1.058-1.251), p  = 0.001].

CONCLUSIONS

Mothers of preterm infants at the limit of viability had more ART, multiple pregnancies, obstetrical complications and C-section. Infants' survival was independently associated to antenatal steroids, singleton pregnancy, temperature on admission and CRIB score.