Effect of latency period after premature rupture of membranes on 2 years infant mortality (DOMINOS study).

Objective: To assess the impact of a short latency period after preterm premature rupture of the membranes (PPROM) on infant mortality.
Study Design: A prospective cohort study of women with PPROM between 24(0/7) and 33(6/7) weeks' in singleton gestation was performed in all maternity wards of the Rhône-Alpes Region. Neonatal and infant outcomes were compared according to the latency period (<48 h and > or =48 h). The primary outcome was the mortality rate and the secondary outcome was a composite variable of significant neurological disorders at 2 years of age. Outcomes was stratified according to gestational age at rupture. Univariate and multiple logistic regression analyses were used with SAS statistical software.
Results: Out of 471 women recruited in the study at a mean gestational age of 30.5+/-0.2 weeks, 170 (37%) presented with a <48-h latency period, and 301 (63%), a > or =48-h latency period. While prior to 30 weeks' gestation, the mortality rate was higher in neonates with a short latency period (16.3% versus 7.3%, p < 0.01) with pulmonary disease being the major cause of death, a short latency period was associated with a lower mortality rate after 30 weeks' gestation (0% versus 3.7%, p=0.02). After adjusting for confounding factors, a <48-h latency period remained an independent factor associated with infant mortality prior to 30 week's gestation (odds ratio 3.8, 95% confidence interval 1.3-11.7). Significant neurological disorders were not modified by the length of the latency period.
Conclusion: For PPROM that occur before 30 weeks' gestation, a short latency period was associated with a higher infant mortality rate. Inversely, it was associated with a lower mortality rate after 30 weeks'. There is an urgent need for a thorough evaluation of expectant management of PPROM after 30 weeks' gestation.