The outcome was lethal in 67/395 (17%) patients of which 55% had chorioamnionitis (p > 0.05).In comparison with the control group, mortality was significantly higher in the group of premature infants with gestation at or before 28 weeks whose placentas showed chorioamnionitis (p 0.05). In conclusion, premature neonates from pregnancies complicated by chorioamnionitis are more often born at or before 28 weeks of gestation, and chorioamnionitis in such neonates leads to a significantly higher rate of mortality. A greater incidence of EONS was proven in the group of infants with chorioamnionitis.
The difference between the incidence of BPD in preterm infants born from pregnancies complicated by chorioamnionitis and the control group was not significant, however. Gomez et al (1998)53, studied that the fetal inflammatory response syndrome (FIRS) is characterized by activation of the innate immune system of the fetus exposed to infection/inflammation in utero. FIRS was originally defined on the basis of increased cord blood concentrations of interleukin (IL)-6, which was shown associated with adverse neonatal outcome.
Meanwhile, many other soluble blood markers for FIRS, mainly proinflammatory cytokines like IL-1 and tumour necrosis factor (TNF ), have been introduced and histological funisitis/chorionic vasculitis has been suggested as the histological counterpart of FIRS.Driscoll (1986)54, concluded that of these criteria, intrapartum maternal fever appears to be the most frequent. When at least 2 of the aforementioned criteria are present, the risk of neonatal sepsis is increased. Each clinical sign and symptom of chorioamnionitis, however, is by itself of low predictive value. The signs and symptoms of maternal chorioamnionitis or amniotic fluid infection are very subjective.
Moreover, silent chorioamnionitis is prominent, and thus signs and symptoms in the infected newborn infant take on added significance. Fig 1. Schematic illustration of different approaches to define chorioamnionitis and their interrelationship. Prolonged rupture of membranes:Madan et al (2010)55, studied that the risk of neonatal infection increases as the duration of ruptured membranes lengthens. Chorioamnionitis may initiate uteroplacental bleeding or placental abruption. Intrauterine infection is increased in placenta previa and manifests with vaginal bleeding. Labor and delivery may be rapid in the presence of chorioamnionitis. Alternatively, the infection may cause uterine atony, requiring labor to be augmented with oxytocin. Ultimately, a poor labor pattern may require an instrumented delivery or a caesarean delivery. Each of these antepartum and intrapartum factors must be considered when evaluating the newborn for the presence of bacterial infection.Rupture of membranes more than 18 hours before labor, is found in approximately 8%-10% of all pregnancies (Kilbride & Thibeault, 2001)29. Prolonged rupture of the membrane is an important risk factor for both early onset neonatal sepsis (EONS) and preterm births. Many studies have determined that, besides prematurity being the most common problem, infection was the most serious event and potential complication following prolonged rupture of membranes. This became even more serious if both were combined (Boskabadi et al, 2011). Prolonged rupture of the membrane is significant not only in perinatal morbidity and mortality but also in the long term neonatal complications and sequelae in surviving neonates. Improved prenatal care and antenatal antimicrobial treatment of women with a history of prolonged rupture of the membrane had significantly improved neonatal outcome in association with early detection of sepsis and its aggressive management in neonates (Al-Qaqa & Al-Awaysheh, 2005)4.Rupture of membrane longer than 24hours is considered to be a prolonged rupture and is one of the risk factors for neonatal sepsis. Some texts describe a cut off of more than 18 hrs to be a risk factor for early onset Group B streptococcus infection. Aspiration and ingestion of the infected amniotic fluid may lead to congenital pneumonia or systemic infection, which are manifested before delivery by fetal distress or tachycardia. Acquisition of infection during the process of delivery leads to overt manifestations after 1-2 days. Premature rupture of membranes:This refers to spontaneous rupture of membranes any time during pregnancy beyond 28th week but before the onset of labour (labour should not begin within one hour of rupture). Chance of ascending infection is more if labour fails to start within 24 hrs. The attack rate of neonatal sepsis is 10.7% after 24 hours (Dutta,1995)57. Premature rupture of membranes plus 2 more risk factors raises the risk of neonatal sepsis to 25 fold (Hankins et al, 2002)58. In most cases, this occurs near term, but when membrane rupture occurs before 37 weeks’ gestation, it is known as preterm PROM. Preterm PROM complicates approximately 3 per cent of pregnancies and leads to one-third of preterm births. It increases the risk of prematurity and leads to a number of other perinatal and neonatal complications, including a 1 to 2 percent risk of fetal death. Physicians caring for pregnant patients should be versed in the management of preterm PROM because rapid diagnosis and appropriate management can result in improved outcomes (Meis et al, 1987).Maternal Peripartum Infection:Chorioamnionitis and intrapartum fever more than 100.4 F/ 380 C are considered to be major risk factors for neonatal sepsis, while intrapartum fever more than 99.5 F /37.50 C and Group B streptococcus colonisation are minor risk factors (Guerina, 1998)60. Meconium stained liquor:Meconium staining often occurs in conjunction with other causes of fetal distress. It is rare in babies born before 34 weeks gestation. Thirteen per cent of all live births has meconium-stained liquor (Walsh & Fanaroff, 200761).Joachim et al (1999)62, conducted a study to define perinatal factors associated with early-onset neonatal sepsis. Maternal and neonatal variables were analysed retrospectively in 343 infants born before 35 weeks using univariate and multivariate statistical analysis. Logistic regression analysis identified risk factors for probable neonatal sepsis as gestational age at delivery (odds ratio 0.9, 95% confidence interval (CI) 0.91-0.96), premature rupture of membranes (odds ratio 2.9, 95% CI 1.004-8.56), Apgar score