[Perinatal risk factors for infection in the newborn. Multicenter clinico-epidemiologic investigation]

The neonate, in particular if preterm, has a specific immunological system that makes him/her more susceptible to infections which are still a major cause of mortality and morbidity. The early onset infective patterns are often vertically transmitted from the mother to the fetus in the perinatal period. Some mother conditions like genitourinary infections, pre-delivery fever, PROM, pPROM, preterm delivery, abortions, fetal demise are important neonatal risk factors. The role of these factors as causes of early onset neonatal infections was evaluated by an Italian multicentric epidemiologic investigation supported by the MIUR. Mothers admitted to obstetrician hospitals for parturition were studied in a case control retrospective analysis. Mothers presenting with the selected risk factors were the cohort of cases while the admissions without risk factors next to each case represented the controls. The following risk factors were considered for analysis: 2nd trimester abortion, PROM, pPROM, preterm delivery and fetal demise. Eight hospitals entered the multicentric research and 29610 patients have been analyzed: 2466 PROM, 478 pPROM, 946 preterm delivery, 244 abortions, 133 fetal demise. Every woman received a microbiological screening by cervico-vaginal and rectal swab and/or urine culture. As much as 3892 cases from the University Hospitals of Parma and Torino concern, the cervicovaginal swab was positive in 76.5% pPROM, in 50.6% PROM and 50.5% preterm deliveries. The positivity of the swabs showed statistical relevance in cases compared to controls. In cases presenting with abortion the frequency of positive cultures (44.1%) was higher than the controls, but it did not reach statistical relevance. Conversely, positivity of cultures was lower in cases with fetal demise than control group but without statistical difference. In the cohort of 675 women selected from our Institute (University of Parma) the overall rate of positivity of cervico-vaginal swabs was about 44% and only one germ was isolated in 94.6% cases: 49,8% Gram positive and negative, 14.1% Streptococcus hemolyticus B group, 34.7% Candida. The rate of cultural tests performed before delivery was statistically higher in cases than controls (74.3% vs 23.2%, p < 0.001). Furthermore 14.3% newborns from mothers in the case group and 2.3% newborns from mothers in the control group were admitted to the neonatal care unit. Among them 8.4% and 1.2% respectively needed antibiotics while 0.4% and 0.2% respectively presented with early onset infection. Ear swabs were performed in 48,8% of infants born to mothers from the case group and in 26.9% of infants born to mothers from the control group, in 6.5% and in 2.9% respectively were the skin swabs performed as well. No statistical difference was met. The choice to perform cultural examinations was statistically higher in cases than controls, but the positivity rate was similar in both groups, perhaps because of a more specific choice in the control group.

our data confirm the relationship between infections and preterm delivery, PROM, pPROM and support the hypothesis that infections might be the cause of these conditions and not simply an association. A prompt maternal microbiological control during pregnancy and delivery, especially in women presenting with known risk factors, gives the possibility to do early diagnostic-therapeutic interventions and to minimize the frequency and severity of early sepsis in newborns.