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.