Intrauterine infection and spontaneous midgestation abortion: Is the spectrum of microorganisms similar to that in preterm labor?

Abstract

Objective: To determine whether microorganisms associated with intrauterine infection and preterm labor play a contributing role in midgestation abortion.Methods: A 4 year retrospective review of spontaneous midgestation abortions for which autopsy and microbiological cultures of placental and fetal tissue were performed was conducted for a tertiary obstetrics hospital, which included a regional referral service for perinatal and fetal pathology. One hundred twenty-nine spontaneously delivered, nonmacerated, midgestation fetuses or stillbirths (of between 16 and 26 weeks' gestation) and placentas were examined and cultured for aerobic and anaerobic bacteria, yeasts, and genital mycoplasmas.Results: Microorganisms were recovered in 85 (66%) cases (57% placentas, 49% fetuses). Among the culture positive cases, 81% had histological chorioamnionitis, 28% fetal pneumonitis, 38% clinical signs of infection, and 62% ruptured membranes at the time of miscarriage. These differed significantly from culture-negative cases (44%, 5%, 13%, and 34%, respectively). Group B streptococcus (GBS) was the most significant pathogen, recovered in 21 cases, 13 as the sole isolate, 94% with chorioamnionitis, and 47% in women with intact membranes. Escherichia coli and Ureaplasma urealyticum (22 and 24 cases, respectively) occurred mostly as mixed infections, with ruptured membranes. GBS, U. urealyticum, and Streptococcus anginosus group were individually associated with chorioamnionitis, Bacteroides/Prevotella and S. anginosus with fetal pneumonitis. The spectrum of microorganisms was similar to that in preterm labor at later gestations; however, GBS appeared to be the most significant pathogen in midgestation miscarriage, especially with intact membranes.Conclusions: Unsuspected intrauterine infection underlies many spontaneous midgestation abortions. GBS is a key pathogen in this setting. Infect. Dis.

Prevalência da colonização pelo estreptococo do grupo B em gestantes atendidas em ambulatório de pré-natal

“…Embora a colonização por EGB seja citada na literatura como causa de abortamento entre as mulheres 22 , este estudo encontrou que a prevalência de EGB foi duas vezes maior nas mulheres sem história de aborto espontâneo prévio.…”

Colonization of second-trimester placenta parenchyma

“…Such an undesirable result might occur if the placenta fails at its filtering/removal function and lets microorganisms survive and invade feta tissues. 30 Indeed, one could argue that the higher levels of bacterial isolation from vaginally delivered placentas simply indicate that the fetus senses a hostile microbiologic environment and signals the host in such a way as to escape from this environment. 31 Because the normal route of delivery is through the birth canal, the delivered fetus requires some rudimentary protection in place as it passes through an area containing large numbers of microorganisms.…”

Prevalence of colonisation with group B Streptococci in pregnant women of a multi-ethnic population in The Netherlands

“…McDonald and Chambers [37] stated that GBS was a key pathogen in unsuspected intrauterine infections underlying spontaneous midgestation abortions. The study of Daugaard et al [38] demonstrated an association between the occurrence of group B Streptococci in the urine and cervix and late spontaneous abortions, but El Kersh et al [24] found no correlation with a history of repeated spontaneous miscarriages.…”