Adjunctive antibiotic treatment in preterm labor and neonatal morbidity: a meta-analysis

An Overview of Systematic Reviews of Randomized-Controlled Trials for Preventing Necrotizing Enterocolitis in Preterm Infants

Necrotizing enterocolitis (NEC) remains a major cause for neonatal mortality and morbidity in preterm infants. The purpose of this review was to summarize evidence from systematic reviews of randomized-controlled trials (RCTs) regarding antenatal and postnatal interventions for preventing NEC. PubMed, EMBASE, the Cochrane Library Databases, Database of Abstracts of Reviews of Effects, and Campbell Library were searched for meta-analyses in which NEC was reported as an outcome after antenatal or postnatal strategies. The AMSTAR instrument was used to evaluate quality of included reviews. Grading of Recommendations, Assessment, Development and Evaluation assessment was used to evaluate certainty of evidence. We identified 98 meta-analyses of RCTs. The quality of included reviews was adequate, whereas the certainty of evidence was moderate to very low. Moderate certainty evidence showed a reduction in NEC following administration of a combination of species of probiotics, probiotics (any), antenatal corticosteroids in pregnant women at risk of preterm birth, and ibuprofen versus indomethacin for treatment of patent ductus arteriosus (PDA). For surgical NEC, moderate certainty evidence showed an increased risk with lower (85-89%) oxygen saturation target levels, compared with higher (91-95%) oxygen saturation target levels. In conclusion, decreased risk of NEC is observed with probiotics, antenatal corticosteroids for women at risk of preterm birth, and ibuprofen versus indomethacin for treatment of PDA. Targeting lower oxygen saturations may increase the risk of surgical NEC, compared to targeting higher saturations.

The coagulation system of extremely preterm infants: influence of perinatal risk factors on coagulation

OBJECTIVE

Little is known about the influence of preterm delivery and perinatal risk factors on development and expression of the coagulation system in extremely preterm infants. The objective of this study was to determine reference values for the components of the coagulation system at the first day of life in extremely preterm infants.

STUDY DESIGN

Components of the coagulation system were examined retrospectively in 132 extremely preterm infants. Patients were grouped according to clinical criteria for preterm delivery: group A: maternal indication; group B: uteroplacental dysfunction; group C: systemic inflammation.

RESULT

Levels of coagulation factors VII and X rose with increasing gestational age, whereas fibrinogen and coagulation factors II, V and VIII remained constant. Levels of factors V and VIII were higher than those of vitamin K-dependent factors. If preterm delivery was caused by placental disorder (group B) or chorioamnionitis (group C), levels of factor II, VIII and X were significantly lower, whereas factor V and VII levels did not differ. In group C fibrinogen levels in group C were higher compared with group A.

CONCLUSION

Identification of perinatal risk factors may help to define patients at risk of bleeding disorders.

Elevated interleukin-6 concentration and alterations of the coagulation system are associated with the development of intraventricular hemorrhage in extremely preterm infants

BACKGROUND

Pathogenesis of intraventricular hemorrhage (IVH) in premature infants is multifactorial. Little is known about the influence of pro-inflammatory cytokine activation on the coagulation system in extremely preterm infants and its impact on the development of IVH.

OBJECTIVE

To determine the interaction between serum interleukin-6 (IL-6) and the coagulation system in preterm infants predisposed to the development of IVH.

METHODS

Vitamin K-dependent coagulation factors were examined retrospectively in 132 extremely preterm infants prior to vitamin K administration at the first day of life. Patients were grouped according to the occurrence of IVH and serum concentration of IL-6 >/<100 pg/ml.

RESULTS

Occurrence of IVH was associated with clinical diagnosis of chorioamnionitis, low gestational age, high CRIB score, air leak, catecholamine treatment, low initial hematocrit and increased serum concentration of IL-6. Infants developing IVH showed a diminished coagulation profile. Multivariable logistic regression analysis revealed decreased activity of coagulation factor VII, development of pneumothorax and low hematocrit as independent risk factors for the development of IVH. An increased IL-6 serum concentration was associated with a significantly decreased activity of coagulation factor VII and increased levels of fibrinogen.

CONCLUSIONS

The association of elevated IL-6 levels with alterations of the coagulation profile and development of IVH found in our study supports the assumption of a close pathophysiological relation between inflammation and IVH.

Intrapartum antibiotic exposure and early neonatal, morbidity, and mortality in Africa

BACKGROUND

Infants born to women who receive intrapartum antibiotics may have higher rates of infectious morbidity and mortality than unexposed infants.

OBJECTIVE

Our goal was to determine the association of maternal intrapartum antibiotics and early neonatal morbidity and mortality.

METHODS

We performed secondary analysis of data from a multisite randomized, placebo-controlled clinical trial of antibiotics to prevent chorioamnionitis-associated mother-to-child transmission of HIV-1 and preterm birth in sub-Saharan Africa. Early neonatal morbidity and mortality were analyzed. In an intention-to-treat (ITT) analysis, infants born to women randomly assigned to antibiotics or placebo were compared. In addition, non-ITT analysis was performed because some women received nonstudy antibiotics for various clinical indications.

RESULTS

Overall, 2659 pregnant women were randomly assigned. Of these, 2466 HIV-1-infected and HIV-1-uninfected women delivered 2413 live born and 84 stillborn infants. In the ITT analysis, there were no significant associations between exposure to antibiotics and early neonatal outcomes. Non-ITT analyses showed more illness at birth (11.2% vs 8.6%, P = .03) and more admissions to the special care infant unit (12.6% vs 9.8%, P = .04) among infants exposed to maternal intrapartum antibiotics than among unexposed infants. Additional analyses revealed greater early neonatal morbidity and mortality among infants of mothers who received nonstudy antibiotics than of mothers who received study antibiotics.

CONCLUSIONS

There is no association between intrapartum exposure to antibiotics and early neonatal morbidity or mortality. The associations observed in non-ITT analyses are most likely the result of women with peripartum illnesses being more likely to receive nonstudy antibiotics.

Racial disparities in infant mortality: a quality of care perspective

Black infants in the United States are more than twice as likely to die as White infants in the first year of life. Reducing the existing racial disparity in infant mortality rates is a major health policy focus. Despite decades of research aimed at reducing preterm births, our efforts have been largely unsuccessful. Much greater success has been achieved in reducing the morbidity and mortality of premature infants, largely through improvements in obstetrical and neonatal care. However, it is an open question whether such improvements have reduced racial disparities in infant mortality. In this article, we recommend a new framework for addressing infant mortality disparities. We suggest that a quality of care problem may partially underlie racial disparities in infant mortality rates.

The effect of second-trimester antibiotic therapy on the rate of preterm birth

OBJECTIVE

As many as 50% of spontaneous preterm births are infection-related, with Mycoplasma species being the most common microbial isolates from the amniotic cavity. The goal of our study was to evaluate the effect of macrolides, a specific group of antibiotics known to be effective against Mycoplasma species, on the rate of preterm births.

METHODS

We performed a systematic review of the literature and a meta-analysis. We searched PubMed, Medline (1965-March 2006), Embase, and the Cochrane Library, using the key words "pregnancy," "macrolides," "erythromycin," "azithromycin," and "clarithromycin." The research was limited to randomized controlled trials and to human females. Studies included for analysis were of women in the second trimester of pregnancy who received either macrolides or placebo (or no treatment) in order to prevent preterm delivery with at least 95% of patient follow-up. We excluded studies involving women with preterm premature rupture of membranes or regular uterine contractions. Meta-analysis of the retrieved data was performed using RevMan 4.2.8 (Cochrane Collaboration) with dichotomous analyses and delivery prior to 37 weeks' gestation as the primary outcome. The analysis was subsequently repeated using the same methodology for clindamycin and metronidazole administered during the second trimester.

RESULTS

Of the 61 articles yielded by our search, three original papers, investigating a total of 1807 women, examined macrolide utilization and met our criteria. Women included in our analysis were all considered to be at higher risk for preterm delivery (vaginal fetal fibronectin positivity, urogenital Mycoplasma infection, prior preterm delivery, and/or pregestational maternal weight < 50 kg). Compared with placebo, macrolides were associated with a lower rate of preterm births (odds ratio [OR] 0.72; 95% confidence intervals [CI] 0.56-0.93), as was clindamycin (OR 0.68; 95% CI 0.49-0.95). On the other hand, metronidazole (OR 1.10; 95% CI 0.95-1.29) was not linked with significant changes in the rate of preterm births. A higher rate of preterm delivery was found when mid-trimester metronidazole was the only antibiotic administered (OR 1.31; 95% CI 1.08-1.58).

CONCLUSION

Macrolides and clindamycin, given during the second trimester of pregnancy, are associated with a lower rate of preterm delivery, whereas second-trimester metronidazole used alone is linked with a greater risk of preterm delivery in a high-risk population. Use of metronidazole, a common treatment for bacterial vaginosis and Trichomonas vaginalis, should be avoided during the second trimester of pregnancy in this population.

The HPTN 024 Study: the efficacy of antibiotics to prevent chorioamnionitis and preterm birth

OBJECTIVE

The use of antibiotics to prevent preterm birth has achieved mixed results. Our goal in this study was to determine if antibiotics given prenatally and during labor reduce the incidence of preterm birth and histologic chorioamnionitis.

STUDY DESIGN

A double-blind randomized placebo-controlled trial of antibiotics to reduce preterm birth was conducted in 4 African sites. Both HIV-infected and uninfected pregnant women were given 2 courses of antibiotics, prenatally at 24 weeks (metronidazole 250 mg and erythromycin 250 mg tid orally for 7 days), and during labor (metronidazole 250 mg and ampicillin 500 mg q 4 hours) or identically appearing placebos. Two thousand ninety-eight HIV-infected and 335 HIV-uninfected women had evaluable end points, including gestational age determined by both obstetric and pediatric criteria and birth weight (BWT). Pre- and post-treatment rates of various sexually transmitted infections (STI) were determined and placentas were evaluated for histologic chorioamnionitis.

RESULTS

Comparing antibiotic versus placebo treated HIV-infected and uninfected women, there were few differences in mean gestational age at delivery, the percent of preterm births, the time between randomization and delivery, or BWT. Four weeks after the 24-week antibiotic/placebo course, bacterial vaginosis, and trichomoniasis were reduced by 49% to 61% in the antibiotic groups compared with the placebo groups. However, in both the HIV-infected and uninfected groups, the placentas showed no difference in the rate of histologic chorioamnionitis. There were significant differences between HIV-infected and uninfected women, with the former having less education, a history of more stillbirths, more STIs, and in this pregnancy, a lower BWT (2949 vs 3100 g, P < .0001).

CONCLUSION

Despite reducing the rate of vaginal infections, the antibiotic regimen used in this study did not reduce the rate of preterm birth, increase the time to delivery, or increase BWT. Failure of this regimen to reduce the rate of histologic chorioamnionitis may explain the reason the antibiotics failed to reduce preterm birth.

Recent pharmacological advances in the treatment of preterm membrane rupture, labour and delivery

Preterm delivery (before 37 completed weeks of gestation) is the major determinant of infant mortality. In women with a previous preterm birth associated with bacterial vaginosis, prophylactic antibiotics (e.g., metronidazole) reduce the risk of preterm birth and low birth weight. Trichomonas vaginalis increases the risk of preterm delivery, but metronidazole is not beneficial for this and may even be detrimental. Antibiotic use (e.g., erythromycin) prolongs pregnancy in late premature rupture and has health benefits for the neonate. However, antibiotics are probably not useful in preterm labour. Intramuscular 17alpha-progesterone and vaginal progesterone reduce the rate of preterm labour in high-risk pregnancies, including previous spontaneous preterm delivery. Magnesium sulfate, beta2-adrenoceptor agonists and the oxytocin-receptor antagonist, atosiban, are effective in reducing uterine contractions short-term, but there is little evidence that this leads to improved outcomes for the neonate. However, tocolysis with calcium-channel blockers does seem to lead to better outcomes for the neonate. Fetal side effects, such as ductus arteriosus constriction and impaired renal function, are associated with the inhibition of prostaglandin synthesis with indomethacin. New approaches and more effective drugs are required in the treatment of preterm delivery.

Infection as a cause of preterm birth

In summary, there is little question that intrauterine and some extrauterine infections play important roles in the etiology of early, spontaneous, preterm labor and PROM. Disappointing are the mixed results from various treatment attempts, usually with antibiotics, to reduce the preterm birth rate. Clearly, a better understanding of the pathways leading from infection to preterm birth will be necessary to develop effective interventions to reduce infection-related preterm delivery. Research must also address the question of individual susceptibility to infections and the influence of other exposures that may moderate the association between infection and preterm birth.

The effect of antibiotic therapy on intrauterine infection-induced preterm parturition in rabbits

OBJECTIVE

The purpose of this study was to determine whether early antibiotic administration to pregnant rabbits with intrauterine infection could prevent preterm delivery and perinatal mortality.

STUDY DESIGN

Under hysteroscopic guidance, pregnant rabbits at 70% gestation (21 days) were allocated to three groups: (1) control group, transcervical inoculation of 0.2 ml phosphate-buffered saline (n = 16); (2) infection group, transcervical inoculation of 0.2 ml of 10(5) colony-forming units (CFU) of Escherichia coli (n = 21); (3) infection and antibiotics group, transcervical inoculations of 0.2 ml of 10(5) CFU of E. coli and ampicillin-sulbactam 150 mg/kg every 8 h intramuscularly (n = 32). To examine the consequences of treatment delay, animals in the latter group were subdivided to receive antibiotics at different time intervals of 0, 6, 11 and 18 h after bacterial inoculation. The intervals from bacterial inoculation to delivery and litter survival were documented. Systemic (rectal) temperatures were recorded at 4 h intervals through the first 36 h and every 12 h until delivery. A p value of < 0.05 was considered significant.

RESULTS

All rabbits inoculated with E. coli without antibiotic treatment delivered prematurely. The median inoculation-to-delivery interval was significantly shorter in the infected group than in the control group (median 32 h, range 14.9-76.5 h vs. median 219 h, range 173-246 h, respectively; p < 0.0001). Antibiotic administration within 12 h of inoculation, but not after 18 h, increased duration of pregnancy (by reducing the rate of preterm delivery) and neonatal survival (0% vs. 71%; p < 0.0001). The mean temperatures at delivery of animals whose treatments began at 6 and 11 h post-inoculation were significantly lower than those untreated with antibiotics or those treated at 18 h post-inoculation (p < 0.0001 for each comparison).

CONCLUSIONS

Antibiotic administration can prolong pregnancy and reduce perinatal mortality if administered early (within 12 h of microbial inoculation) in a rabbit model of ascending intrauterine infection.

Effect of maternal antibiotic treatment on fetal periventricular white matter cell death in a rabbit intrauterine infection model

AIM

To evaluate the effects of maternal antibiotic treatment on fetal brain cell death in a rabbit intrauterine infection model.

METHODS

After Escherichia coli uterine-horn inoculation in 22 pregnant rabbits, followed at various times by ceftriaxone and caesarean section, cell death in white matter (histology and fragmented DNA staining) from fetuses killed at extraction was compared across groups using the Mantel-Haenszel test and Fisher's exact test for small numbers.

RESULTS

White matter cell death was consistently present at 48 h, with ceftriaxone initiation at 24 h (group 1), detectable at 84 but not 60 h, with ceftriaxone initiation at 12 h, and significantly reduced at 84 h with ceftriaxone initiation at 6 h (60% vs 100% in group 1, p < 0.001, Fisher's exact test).

CONCLUSION

Early maternal antibiotic therapy delays white matter cell death in rabbit fetuses exposed to intrauterine infection. This may provide a window for preventing white matter damage.

Intrauterine infection and prematurity

Intrauterine infection is a major cause of premature labor with and without intact membranes. Intrauterine infection is present in approximately 25% of all preterm births and the earlier the gestational age at delivery, the higher the frequency of intra-amniotic infection. Microorganisms may also gain access to the fetus before delivery. A fetal inflammatory response syndrome elicited in response to microbial products is associated with the impending onset of preterm labor and also with multi-systemic organ involvement in the human fetus and a higher rate of perinatal morbidity. The most common microorganisms involved in intrauterine infections are Ureaplasma urealyticum, Fusobacterium species and Mycoplasma hominis. The role of Chlamydia trachomatis and viruses in preterm labor remain to be determined. Use of molecular microbiology techniques to diagnose intrauterine infection may uncover the role of fastidious microorganisms that have not yet been discovered. Antibiotic administration to patients with asymptomatic bacteriuria is associated with a significant reduction in the rate of preterm birth. However, such benefit has not been demonstrated for patients with bacterial vaginosis, or women who carry Streptococcus agalactia, Ureaplasma urealyticum or Trichomonas vaginalis. Antibiotic administration to patients with preterm premature rupture of membranes is associated with prolongation of pregnancy and a reduction in the rate of clinical chorioamnionitis and neonatal sepsis. The benefit has not been demonstrated in patients with preterm labor and intact membranes. Major efforts are required to determine why some women develop an ascending intrauterine infection and others do not and also what interventions may reduce the deleterious effect of systemic fetal inflammation.

Perinatal risk factors for adverse neurodevelopmental outcome after spontaneous preterm birth

OBJECTIVE

The aim of this study was to investigate to what extend perinatal factors contribute to the neurodevelopmental outcome in a group neonates born after spontaneous preterm labour with or without prolonged rupture of the membranes (PROM).

METHODS

In a cohort of neonates born after the spontaneous onset of labour with or without PROM before 34 weeks of gestation a stepwise forward logistic regression was performed to analyse the influence of antenatal and postnatal variables on adverse outcome. Adverse neurodevelopmental outcome was defined as a Griffith's developmental score <85, cerebral palsy, a major disability or perinatal death associated with severe cerebral damage.

RESULTS

The study group consisted of 185 neonates. Seven neonates died with severe cerebral damage. After a forward logistic regression analysis three factors appeared to have an independent influence: gestational age protected against an adverse outcome (odds ratio (OR) per day increase 0.95, 95% confidence interval (CI) 0.90-0.97) while abnormal cranial ultrasound (intraventricular haemorrhage and periventricular leucomalacia) (OR 6.33, 95% CI 2.16-18.52) and the need for a second course of antibiotics (OR 1.85, 95% CI 1.02-3.33) increased the risk for adverse outcome. Comparing the group with a normal neurodevelopmental outcome with those with cerebral palsy, cranial ultrasound abnormalities were independently associated with cerebral palsy (OR 48.75, 95% CI 11.78-201.76).

CONCLUSION

The most important way of preventing neurological damage in infants is to increase gestational age at birth and to avoid the development of intraventricular haemorrhage and periventricular leucomalacia.

Antenatal corticosteroids in women with preterm premature rupture of the membranes

The authors believe that the literature provides sufficient evidence that antenatal corticosteroid administration is beneficial and safe even in conditions of ruptured membranes. The evidence by now is remarkably robust and one can be reasonably confident regarding the benefits of antenatal corticosteroids in the setting of ruptured membranes. As recently stated by a group of investigators from New Zealand, including Liggins, the originator of this historical medical intervention (antepartum corticosteroids), the safety and efficacy of corticosteroids in conditions of ruptured membranes is beyond any doubt. It is time to accept this reality and to move on to other unresolved issues, like the optimal dose and corticosteroid preparation, the optimal timing of treatment, or the optimal exposure interval.

The fetal inflammatory response syndrome and cerebral palsy: yet another challenge and dilemma for the obstetrician

There is increasing evidence demonstrating a relationship between intrauterine infection and the development of neonatal intraventricular haemorrhage and periventricular leukomalacia with the subsequent occurrence of cerebral palsy, which is thought to be mediated through the generation of pro-inflammatory cytokines by the fetus. In the light of this relationship, a review of the current management of intrapartum infection and the associated complications of intrauterine infection such as preterm labour and preterm premature rupture of the membranes would seem timely along with the development of potential strategies which might prevent or ameliorate the effects of the fetal inflammatory response syndrome. The suggested changes in the understanding and management of the fetal inflammatory response syndrome provide a challenge and pose a dilemma for the practising obstetrician.

Quality measures of antimicrobial drug use

Antimicrobial use is the major determinant in the development of resistance. Many parameters of importance for optimal quality of antimicrobial therapy have already been defined. Maximal efficacy of the treatment should be combined with minimal toxicity at the lowest cost. Quality of antimicrobial drug use is dependent on knowledge of many aspects of infectious diseases. Considering efficacy, many of our indications for antimicrobial use need critical evaluation. Irrational use should be discouraged. Avoidance of the development of resistance is a quality parameter that will need increasing attention. This paper reviews the well-established factors that may influence the appropriateness of pharmacotherapy with antimicrobial drugs. It cites recent evidence supporting principles of prudent prescribing and gives an overview of audits that have addressed these parameters. Measures relating to resistance are discussed.

Place of amniocentesis in the assessment of preterm labour

OBJECTIVE

To evaluate the benefits and indications for amniocentesis in cases of preterm labor with or without preterm rupture of membranes.

METHOD

A review of the literature on amniocentesis in cases of intra-amniotic infection.

RESULTS

Amniocentesis is an invasive method that allows the diagnosis of intra-amniotic infection. However, no randomized trials have been performed from which we can assess the benefits and complications of amniocentesis in preterm labor.

CONCLUSION

The published data do not justify the routine practice of amniocentesis in preterm labor. More data are needed to evaluate the benefits and complications of this practice. Only randomized trials of patients in preterm labor, comparing those who undergo amniocentesis with those who do not, will clarify the indications for this procedure.

Prenatal screening

The prenatal period is an ideal time to look at screening issues in an effort to maximize the health of the woman and effect a good outcome for her baby. As primary care providers for family, it is important to look beyond a traditional medical model for screening to examine a woman in the context of her family and her experiences. This article takes a broader view of screening to include some social and family issues. It also seeks to examine the evidence around some of the controversial issues in screening to help the provider be a thorough advisor to his or her patients.

Morphology assessed by transvaginal ultrasonography differs in patients in preterm labor with vs. without bacterial vaginosis

OBJECTIVE

To determine whether cervical morphology in preterm labor patients differs in the presence or absence of bacterial vaginosis.

DESIGN

Observational study.

SUBJECTS

One hundred and twelve consecutive patients with objectively confirmed preterm labor admitted to a tertiary care centre were included in the study. Patients with placenta previa, active uterine bleeding or indication for an immediate delivery (e.g. severe pre-eclampsia or suspected fetal asphyxia), or severe fetal anomalies were excluded.

METHODS

Transvaginal ultrasonography was used to measure cervical length and internal os width. Bacterial vaginosis was diagnosed by Gram stain of a vaginal smear.

RESULTS

A total of 36 patients (32%) had bacterial vaginosis. Cervical length in this group was shorter than in patients with normal flora (mean 20.4 +/- 7.2 mm vs. 26.4 +/- 6.7 mm; P = 0.0002), and more patients with bacterial vaginosis had a dilated internal cervical os > or = 5 mm (67% vs. 30%, P = 0.001). There were no significant differences, however, in preterm delivery rate and birth weight between the two groups; the overall preterm delivery rate was 40%. A cervical length < 25 mm was predictive of preterm delivery (P = 0.001, RR 4.2, 95% CI 1.8-9.7).

CONCLUSIONS

These data suggest that cervical change in preterm labor is more pronounced in patients with bacterial vaginosis but without a concomitant increase in the risk for preterm delivery. Despite this association, the cervical length measured by transvaginal ultrasonography alone is a useful predictor of preterm delivery, independent of the presence or absence of bacterial vaginosis.

Low-birthweight prevention programs: the enigma of failure

BACKGROUND

Low birthweight is the primary cause of neonatal morbidity and mortality in the United States. The purpose of our study was to identify factors associated with the effectiveness and apparent ineffectiveness of comprehensive, multicomponent, prenatal care programs for preventing low birthweight.

METHODS

We reviewed obstetric, pediatric, and public health program evaluations, research reports, and commentaries, published in the English language literature, over the last four decades that pertained to the efficacy of prenatal care for preventing low birthweight.

RESULTS

The heterogeneous nature of the services delivered and the lack of consistency in the definition of variables made it impossible to use rigorous, quantitative techniques to summarize this evaluation of the literature. Two general limitations of research design that emerged from our reviews were the focus on clusters of commonly associated risk factors, which has blurred the causal pathways linking specific risk factors to low birthweight, and the failure to examine process variables. These two methodologic problems have led investigators to erroneous conclusions that overstate the significance of negative intervention outcomes. The success and failure of low-birthweight prevention programs has rarely been examined in relation to evidence that the intervention actually modified the targeted risk factors.

CONCLUSIONS

Few rigorous evaluations of well-designed programs have been conducted. Without an improvement in intervention designs and evaluation studies, recommendations to support or curtail the funding of comprehensive, multicomponent prenatal care services are inappropriate. Rigorously obtained evidence of the costs and benefits of approaches to the prevention of low birthweight are sorely needed.

Antibiotics: treatment of preterm labor

Our intention is to review recent data and provide recommendations for the use of antibiotics in cases of preterm labor or preterm premature rupture of the membranes (pPROM). Various studies assessing antibiotics as treatment for preterm labor demonstrate neonatal or maternal benefits only in certain circumstances. Antibiotic treatment should be given to patients with bacterial vaginosis and Trichomonas vaginalis. Currently, antibiotics should not be applied routinely to prolong pregnancy in women with preterm labor and intact membranes. However, antibiotic therapy should be given to patients with pPROM to prolong pregnancies at 24 to 32 weeks' gestation. Our management of pPROM up to 32 weeks' gestation includes use of corticosteroids, antibiotic (extended spectrum penicillins) and tocolytic treatment for preterm labor and pregnancy prolongation. We consider expectant management previous to evidence of intrauterine infection. In women with pPROM at 32 to 34 weeks we found it beneficial to deliver 24 hours after administration of corticosteroids or, in cases of intrauterine infection, immediately. Finally, we report on our research work regarding fetal brain development in preterm birth. Further studies will be necessary to clarify the role of the interleukin-6/interleukin-6 receptor pathway in the development of intracerebral hemorrhage frequently occuring in premature infants.

Cervicovaginal fetal fibronectin as a marker for preterm delivery: a meta-analysis

OBJECTIVE

We performed a meta-analysis to determine the value of cervicovaginal fetal fibronectin as a marker for preterm delivery.

STUDY DESIGN

Selection criteria confined the analysis to original, English-language reports of prospective studies including women at <37 weeks' gestation with intact amniotic membranes. For the outcomes of delivery at <37 or <34 weeks' gestation or delivery within 7, 14, 21, or 28 days after fibronectin sampling, we calculated sensitivity and specificity rates for each study, for subgroups of studies, and for all studies combined.

RESULTS

A total of 27 studies met our inclusion criteria. For the outcomes of delivery at <37 and <34 weeks' gestation, overall sensitivity rates were 56% and 61% and overall specificity rates were 84% and 83%, respectively. For the outcomes of delivery within 7, 14, 21, and 28 days, we calculated sensitivity rates of 76%, 68%, 61%, and 43% and specificity rates of 88%, 89%, 91%, and 93%, respectively. For the subgroup of patients with symptoms of preterm labor, sensitivity rates for delivery within 7, 14, 21, and 28 days of 89%, 78%, 76%, and 71% and specificity rates of 86%, 86%, 88%, and 83%, respectively, were calculated.

CONCLUSION

Among patients with symptoms of preterm labor, cervicovaginal fetal fibronectin appears to be among the most effective predictors of preterm delivery.

[What is new in neonatology?]

Advances in neonatology have been consistent in recent years, both from practical and theoretical points of view. Improved outcome is the result of major developments in neonatal intensive care, but also of the improved organization of perinatal care. Recent concepts on the inflammatory mechanisms of preterm labor and periventricular leukomalacia are opening a new area for preventive intervention. The observed association between the occurrence of diseases such as hypertension in adulthood and intrauterine growth retardation offers a particular insight into the long term programming of physiologic regulations in the fetus. At the bedside, advances in neonatal intensive care have been significant, especially in treating neonatal respiratory failure. This review will focus on recent developments in premature anemia, and in fluid-electrolyte therapy in very low infant birth weights, as both topics have been less frequently reviewed in the pediatric literature. Finally, ethical issues have deserved considerable attention, such as therapeutic intervention in extremely low birth weight infants, decision-taking, and practices in withholding or withdrawing therapy during neonatal intensive care, along with the need for long term follow up and assistance to the patients and their families.

Recent advances in the therapeutic management of preterm labour

Preterm labour and delivery pose an increasing problem to the obstetrician. Improvements in tocolysis with the recent introduction of new therapeutic targeting strategies, and a reappraisal of the safety and relative efficacy of some older compounds, have led to a tendency away from prescribing beta-sympathomimetic agents. Infection prophylaxis and promotion of fetal lung maturity are deemed advantageous, but treatment protocols have not been clarified. This review examines the important publications of the past year in these areas.

Preterm labour: recent advances in understanding of pathophysiology, diagnosis and management

Recent advances in the importance of sociodemographic factors, including maternal stress, as well as potential predictors of preterm birth are reviewed. The recommended role of adjunctive antibiotic therapy, in women with preterm premature rupture of the membranes but not in women with intact membranes, is discussed. The possibility of causes other than those related to infection in preterm rupture of the membranes is raised, and new information regarding the use of glucocorticoids and tocolytics is presented. Despite steady improvements in neonatal survival and morbidity rates over the past decade primarily as a result of improved neonatal care, there has been no corresponding decrease in the incidence of preterm birth. An improved understanding of the pathophysiology and diagnosis of preterm birth remains one of the greatest challenges in obstetric care in this decade.

Ampicillin-metronidazole treatment in idiopathic preterm labour: a randomised controlled multicentre trial

OBJECTIVE

To determine whether treatment with ampicillin and metronidazole in women with threatened idiopathic preterm labour will prolong the gestation and reduce maternal and neonatal infectious morbidity.

DESIGN

Randomised controlled double-blind trial.

SETTING

Six obstetric departments in the Copenhagen area.

POPULATION

One hundred and twelve women with singleton pregnancies, with threatened idiopathic preterm labour and intact amniotic membranes at 26 to 34 weeks of gestation.

METHODS

Random allocation to eight days intravenous and oral treatment with ampicillin and metronidazole, or placebo.

MAIN OUTCOME MEASURES

Number of days from admission to delivery, gestational age at delivery, rates of preterm delivery, low birthweight, maternal infections and neonatal infections.

RESULTS

Treatment with ampicillin and metronidazole was associated with a significant prolongation of pregnancy (admission to delivery 47.5 days versus 27 days, P < 0.05), higher gestational age at delivery (37 weeks versus 34 weeks, P < 0.05), decreased incidence of preterm birth (42% versus 65%, P < 0.05), and lower rate of admission to neonatal intensive care unit (40% versus 63%, P < 0.05), when compared with placebo treatment. Antibiotic treatment had no significant effects on infectious morbidity.

CONCLUSIONS

Treatment with ampicillin and metronidazole in women with threatened idiopathic preterm labour significantly prolonged the gestation, but had no effects on maternal and neonatal infectious morbidity.

Use of antibiotics to prevent preterm birth

Our purpose is to review recent data and provide a clinical opinion on the use of antibiotics to prevent preterm birth or related maternal-neonatal complications. A literature review and a synthesis of opinion are provided. During prenatal care, standard practices should be applied regarding Neisseria gonorrhoeae, Chlamydia trachomatis, and bacteriuria. In addition, screen for and treat bacterial vaginosis in patients at high risk for preterm birth but do not treat Ureaplasma urealyticum or group B streptococci genital colonization. With preterm labor and intact membranes, standard practices should be applied regarding group B streptococci prophylaxis. Do not give antibiotics routinely to prolong pregnancy, but in patients with bacterial vaginosis and Trichomonas vaginalis specific treatment should be given. With preterm premature rupture of membranes, standard practices should be applied regarding group B streptococci prophylaxis, but additional antibiotics should also be given to prolong pregnancies at 24 to 32 weeks' gestation. Reported adverse effects have been few to date. However, increased diligence is needed for resistant organisms. In selected clinical settings antibiotic therapy is now indicated to prolong pregnancy and prevent maternal-neonatal complications associated with preterm birth.