Antibiotic therapy in preterm premature rupture of membranes: a randomized, prospective, double-blind trial

Efficacy of prophylactic antibiotics for preterm premature rupture of membranes: a systematic review and network meta-analysis

OBJECTIVE

Various prophylactic antibiotic regimens are used in the management of preterm premature rupture of membranes. We investigated the efficacy and safety of these regimens in terms of maternal and neonatal outcomes.

DATA SOURCES

We searched PubMed, Embase, and the Cochrane Central Register of Controlled Trials from inception to July 20, 2021.

STUDY ELIGIBILITY CRITERIA

We included randomized controlled trials involving pregnant women with preterm premature rupture of membranes before 37 weeks of gestation and a comparison of ≥2 of the following 10 antibiotic regimens: control/placebo, erythromycin, clindamycin, clindamycin plus gentamicin, penicillins, cephalosporins, co-amoxiclav, co-amoxiclav plus erythromycin, aminopenicillins plus macrolides, and cephalosporins plus macrolides.

METHODS

Two investigators independently extracted published data and assessed the risk of bias with a standard procedure following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Network meta-analysis was conducted using the random-effects model.

RESULTS

A total of 23 studies that recruited a total of 7671 pregnant women were included. Only penicillins (odds ratio, 0.46; 95% confidence interval, 0.27-0.77) had significantly superior effectiveness for maternal chorioamnionitis. Clindamycin plus gentamicin reduced the risk of clinical chorioamnionitis, with borderline significance (odds ratio, 0.16; 95% confidence interval, 0.03-1.00). By contrast, clindamycin alone increased the risk of maternal infection. For cesarean delivery, no significant differences were noted among these regimens.

CONCLUSION

Penicillins remain the recommended antibiotic regimen for reducing maternal clinical chorioamnionitis. The alternative regimen includes clindamycin plus gentamicin. Clindamycin should not be used alone.

Antibiotic prophylaxis in pregnant with premature rupture of ovular membranes: systematic review and meta-analysis

OBJECTIVE

To perform a systematic review and meta-analysis of randomized clinical trials that compared the use of antibiotics versus placebo in premature rupture of membranes preterm and evaluated maternal, fetal and neonatal outcomes in pregnant women with premature rupture of ovular membranes at a gestational age between 24 and 37 weeks.

METHODS

A search was conducted using keywords in PubMed, Cochrane, Biblioteca Virtual em Saúde and Biblioteca Digital de Teses e Dissertações da USP between August 2018 and December 2021. A total of 926 articles were found. Those included were randomized clinical trials that compared the use of antibiotics versus placebo in the premature rupture of preterm membranes. Articles referring to antibiotics only for streptococcus agalactiae prophylaxis were excluded. The retrieved articles were independently and blindly analyzed by two reviewers. A total of 24 manuscripts met the inclusion criteria and 21 articles were included for quantitative analysis.

RESULTS

Among the maternal outcomes analyzed, there was a prolongation of the latency period that was ≥7 days. In addition, we observed a reduction in chorioamnionitis in the group of pregnant women who used antibiotics. As for endometritis and other maternal outcomes, there was no statistically significant difference between the groups. Regarding fetal outcomes, antibiotic prophylaxis worked as a protective factor for neonatal sepsis. Necrotizing enterocolitis and respiratory distress syndrome showed no statistically significant differences.

CONCLUSION

The study showed positive results in relation to antibiotic prophylaxis to prolong the latency period, new randomized clinical trials are needed to ensure its beneficial effect.

PROSPERO DATABASE REGISTRATION

(www.crd.york.ac.uk/prospero) under number CRD42020155315.

Developing a Core Outcome Set for the Evaluation of Antibiotic Use in Prelabor Rupture of Membranes: A Systematic Review and Semi-Structured Interview

Background: Prelabor rupture of membranes (PROM) is associated with maternal and neonatal infections. Although guidelines suggest prophylactic antibiotics for pregnant women with PROM, the optimal antibiotic regimen remains controversial. Synthesizing the data from different studies is challenging due to variations in reported outcomes.

Objective: This study aimed to form the initial list of outcomes for the core outcome set (COS) that evaluates antibiotic use in PROM by identifying all existing outcomes and patients’ views.

Methods: Relevant studies were identified by searching PubMed, EMBASE, Cochrane Library, Chinese National Knowledge Infrastructure, Wanfang, and VIP databases. We also screened the references of the included studies as a supplementary search. We extracted basic information from the articles and the outcomes. Two reviewers independently selected the studies, extracted the data, extracted the outcomes, and grouped them into domains. Then, semi-structured interviews based on the potential factors collected by the systematic review were conducted at West China Second Hospital of Sichuan University. Pregnant women who met the diagnostic criteria for PROM were enrolled. Participants reported their concerns about the outcomes. Two researchers identified the pregnant women’s concerns.

Results: A total of 90 studies were enrolled in this systematic review. The median outcomes in the included studies was 7 (1–31), and 109 different unique outcomes were identified. Pre-term PROM (PPROM) had 97 outcomes, and term PROM (TPROM) had 70 outcomes. The classification and order of the core outcome domains of PPROM and TPROM were consistent. The physiological domain was the most common for PPROM and TPROM outcomes. Furthermore, 35.1 and 57.1% outcomes were only reported once in PPROM and TPROM studies, respectively. Thirty pregnant women participated in the semi-structured interviews; 10 outcomes were extracted after normalized, and the outcomes were reported in the systematic review. However, studies rarely reported pregnant women’s concerns.

Conclusion: There was considerable inconsistency in outcomes selection and reporting in studies about antibiotics in PROM. An initial core outcomes set for antibiotics in PROM was formed.

Pregnancy latency after preterm premature rupture of membranes: oral versus intravenous antibiotics

BACKGROUND

Following the destruction of pharmaceutical production facilities in Puerto Rico by Hurricane Maria in September 2017, a shortage of small-volume bags of sterile intravenous fluid for infusion led to a decreased ability to administer intravenous azithromycin and ampicillin efficiently for use in the treatment of patients with preterm premature rupture of membranes.

OBJECTIVE

This study aimed to assess pregnancy latency after preterm premature rupture of membranes following treatment with oral-only antibiotics compared with treatment with intravenous antibiotics followed by oral antibiotics.

STUDY DESIGN

This is a retrospective historic control study comparing women with preterm premature rupture of membranes who were initiated on a 7-day oral-only regimen of azithromycin and amoxicillin (modified regimen) during a 12-month period beginning December 2017 (during which time there was a shortage of small-volume bags of intravenous fluid) to women with preterm premature rupture of membranes who were initiated on a 2-day regimen of intravenous ampicillin and azithromycin followed by 5 days of oral amoxicillin and azithromycin (standard regimen) from December 2016 to December 2018. Women were included in the study if they were diagnosed with preterm premature rupture of membranes at <34 weeks' gestation and were started on latency antibiotics, and women were excluded from the study if they had a contraindication to expectant management, a cerclage, or suspected fetal anomalies. The primary outcome was pregnancy latency, defined as time from the first dose of antibiotics to delivery.

RESULTS

The 37 women who received the modified regimen and the 79 women who received the standard regimen had similar baseline characteristics. Mean (standard deviation) gestational age at time of preterm premature rupture of membranes was similar between the modified (30.5 weeks' gestation [±3.1]) and standard regimen groups (30.2 weeks' gestation [±3.2]), and the rate of group B streptococcus rectovaginal colonization was similar for both groups (27% vs 24%; P=.95). Pregnancy latency did not differ in the modified vs standard regimen (mean difference, -0.15 days; 95% confidence interval, -4.87 to 4.58) There was no statistically significant difference in the relative risk of composite maternal infection (relative risk, 0.43; 95% confidence interval, 0.05-3.53) or composite neonatal infection (relative risk, 0.43; 95% confidence interval, 0.05-3.52).

CONCLUSION

Although limited by small sample size, our study suggested that adoption of an oral-only antibiotic regimen for pregnancy latency following preterm premature rupture of membranes is worthy of further study.

Antibiotics for Prophylaxis in the Setting of Preterm Prelabor Rupture of Membranes

"For many years, providers have been using antibiotics to prevent infection in women who present with preterm prelabor rupture of membranes (PPROM). Given the polymicrobial nature of intra-amniotic infection, the recommended regimen includes a 7-day course of ampicillin and erythromycin, although many substitute of azithromycin. This regimen is used from viability to 34 weeks, independent of the number of fetuses present. Meta-analyses have shown that antibiotics for this indication are associated with lower rates of maternal and fetal infection, as well as longer pregnancy latency. Thus, latency antibiotics are recommended for all women with PPROM through 34 weeks of gestation."

Antibiotic administration reduces the rate of intraamniotic inflammation in preterm prelabor rupture of the membranes

BACKGROUND

Preterm prelabor rupture of the membranes (PPROM) is frequently complicated by intraamniotic inflammatory processes such as intraamniotic infection and sterile intraamniotic inflammation. Antibiotic therapy is recommended to patients with PPROM to prolong the interval between this complication and delivery (latency period), reduce the risk of clinical chorioamnionitis, and improve neonatal outcome. However, there is a lack of information regarding whether the administration of antibiotics can reduce the intensity of the intraamniotic inflammatory response or eradicate microorganisms in patients with PPROM.

OBJECTIVE

The first aim of the study was to determine whether antimicrobial agents can reduce the magnitude of the intraamniotic inflammatory response in patients with PPROM by assessing the concentrations of interleukin-6 in amniotic fluid before and after antibiotic treatment. The second aim was to determine whether treatment with intravenous clarithromycin changes the microbial load of Ureaplasma spp DNA in amniotic fluid.

STUDY DESIGN

A retrospective cohort study included patients who had (1) a singleton gestation, (2) PPROM between 24+0 and 33+6 weeks, (3) a transabdominal amniocentesis at the time of admission, and (4) intravenous antibiotic treatment (clarithromycin for patients with intraamniotic inflammation and benzylpenicillin/clindamycin in the cases of allergy in patients without intraamniotic inflammation) for 7 days. Follow-up amniocenteses (7^th day after admission) were performed in the subset of patients with a latency period lasting longer than 7 days. Concentrations of interleukin-6 were measured in the samples of amniotic fluid with a bedside test, and the presence of microbial invasion of the amniotic cavity was assessed with culture and molecular microbiological methods. Intraamniotic inflammation was defined as a bedside interleukin-6 concentration ≥745 pg/mL in the samples of amniotic fluid. Intraamniotic infection was defined as the presence of both microbial invasion of the amniotic cavity and intraamniotic inflammation; sterile intraamniotic inflammation was defined as the presence of intraamniotic inflammation without microbial invasion of the amniotic cavity.

RESULTS

A total of 270 patients with PPROM were included in this study: 207 patients delivered within 7 days and 63 patients delivered after 7 days of admission. Of the 63 patients who delivered after 7 days following the initial amniocentesis, 40 underwent a follow-up amniocentesis. Patients with intraamniotic infection (n = 7) and sterile intraamniotic inflammation (n = 7) were treated with intravenous clarithromycin. Patients without either microbial invasion of the amniotic cavity or intraamniotic inflammation (n = 26) were treated with benzylpenicillin or clindamycin. Treatment with clarithromycin decreased the interleukin-6 concentration in amniotic fluid at the follow-up amniocentesis compared to the initial amniocentesis in patients with intraamniotic infection (follow-up: median, 295 pg/mL, interquartile range [IQR], 72-673 vs initial: median, 2973 pg/mL, IQR, 1750-6296; P = .02) and in those with sterile intraamniotic inflammation (follow-up: median, 221 pg/mL, IQR 118-366 pg/mL vs initial: median, 1446 pg/mL, IQR, 1300-2941; P = .02). Samples of amniotic fluid with Ureaplasma spp DNA had a lower microbial load at the time of follow-up amniocentesis compared to the initial amniocentesis (follow-up: median, 1.8 × 10⁴ copies DNA/mL, 2.9 × 10⁴ to 6.7 × 10⁸ vs initial: median, 4.7 × 10⁷ copies DNA/mL, interquartile range, 2.9 × 10³ to 3.6 × 10⁷; P = .03).

CONCLUSION

Intravenous therapy with clarithromycin was associated with a reduction in the intensity of the intraamniotic inflammatory response in patients with PPROM with either intraamniotic infection or sterile intraamniotic inflammation. Moreover, treatment with clarithromycin was related to a reduction in the load of Ureaplasma spp DNA in the amniotic fluid of patients with PPROM <34 weeks of gestation.

Effect on perinatal outcome of prophylactic antibiotics in preterm prelabor rupture of membranes: network meta-analysis of randomized controlled trials

OBJECTIVES

Prophylactic antibiotics are recommended routinely for preterm prelabor rupture of membranes (PPROM), but there is an abundance of potential treatments and a paucity of comparative information. The aims of this network meta-analysis were to compare the efficiency of different antibiotic regimens on perinatal outcomes and to assess the quality of the current evidence.

METHODS

This was a network meta-analysis of randomized controlled trials comparing prophylactic antibiotics, or regimens of antibiotics, with each other or with placebo/no treatment, in women with PPROM. MEDLINE, Scopus, Cochrane Central Register of Controlled Trials, US Registry of Clinical Trials ( www.ClinicalTrials.gov) and gray literature sources were searched. The primary outcomes were neonatal mortality and chorioamnionitis; secondary outcomes included other measures of perinatal morbidity. Relative effect sizes were estimated using risk ratios (RR) and the relative ranking of the interventions was obtained using cumulative ranking curves. The quality of evidence for the primary outcomes was assessed according to GRADE guidelines, adapted for network meta-analysis.

RESULTS

The analysis included 20 studies (7169 participants randomized to 15 therapeutic regimens). For the outcome of chorioamnionitis, clindamycin + gentamycin (network RR, 0.19 (95% CI, 0.05-0.83)), penicillin (RR, 0.31 (95% CI, 0.16-0.6)), ampicillin/sulbactam + amoxicillin/clavulanic acid (RR, 0.32 (95% CI, 0.12-0.92)), ampicillin (RR, 0.52 (95% CI, 0.34-0.81)) and erythromycin + ampicillin + amoxicillin (RR, 0.71 (95% CI, 0.55-0.92)) were superior to placebo/no treatment. Erythromycin was the only effective drug for neonatal sepsis (RR, 0.74 (95% CI, 0.56-0.97)). Clindamycin + gentamycin (RR, 0.32 (95% CI, 0.11-0.89)) and erythromycin + ampicillin + amoxicillin (RR, 0.83 (95% CI, 0.69-0.99)) were the only effective regimens for respiratory distress syndrome, whereas ampicillin (RR, 0.42 (95% CI, 0.20-0.92)) and penicillin (RR, 0.49 (95% CI, 0.25-0.96)) were effective in reducing the rates of Grade-3/4 intraventricular hemorrhage. None of the antibiotics appeared significantly more effective than placebo/no treatment in reducing the rates of neonatal death, perinatal death and necrotizing enterocolitis. No network RR could be estimated for neonatal intensive care unit admission. The overall quality of the evidence, according to GRADE guidelines, was moderate to very low, depending on the outcome and comparison.

CONCLUSIONS

Several antibiotics appear to be more effective than placebo/no treatment in reducing the rate of chorioamnionitis after PPROM. However, none of them is clearly and consistently superior compared to other antibiotics, and most are not superior to placebo/no treatment for other outcomes. The overall quality of the evidence is low and needs to be updated, as microbial resistance may have emerged for some antibiotics, while others are underrepresented in the existing evidence. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

[Antibiotic prophylaxis in preterm premature rupture of membranes: CNGOF preterm premature rupture of membranes guidelines]

OBJECTIVE

To analyse benefits and risks of antibiotic prophylaxis in the management of preterm premature rupture of membranes.

METHODS

PubMed and Cochrane Central databases search.

RESULTS

Streptoccoccus agalactiae (group B streptococcus) and Escherichia coli are the two main bacteria identified in early neonatal sepsis (EL3). Antibiotic prophylaxis at admission is associated with significant prolongation of pregnancy (EL2), reduction in neonatal morbidity (EL1) without impact on neonatal mortality (EL2). Co-amoxiclav could be associated with an increased risk for neonatal necrotising enterocolitis (EL2). Antibiotic prophylaxis at admission in women with preterm premature rupture of the membranes is recommended (Grade A). Monotherapy with amoxicillin, third generation cephalosporin and erythromycin can be used as well as combination of erythromycin and amoxicillin (Professional consensus) for 7 days (GradeC). Shorter treatment is possible when initial vaginal culture is negative (Professional consensus). Co-amxiclav, aminoglycosides, glycopeptides, first and second generation cephalosporin, clindamycin and metronidazole are not recommended (Professional consensus).

CONCLUSIONS

Antibiotic prophylaxis against Streptoccoccus agalactiae (group B streptococcus) and E. coli is recommended in women with preterm premature of the membranes (Grade A). Monotherapy with amoxicillin, third generation cephalosporin or erythromycin, as well as combination of erythromycin and amoxicillin are recommended (Professional consensus).

A new antibiotic regimen treats and prevents intra-amniotic inflammation/infection in patients with preterm PROM

OBJECTIVES

To determine whether a new antibiotic regimen could reduce the frequency of intra-amniotic inflammation/infection in patients with preterm PROM.

STUDY DESIGN

This retrospective cohort study was conducted to evaluate the effect of antibiotics on the frequency of intra-amniotic inflammation/infection based on the results of follow-up transabdominal amniocenteses from 89 patients diagnosed with preterm PROM who underwent serial amniocenteses. From 1993-2003, ampicillin and/or cephalosporins or a combination was used ("regimen 1"). A new regimen (ceftriaxone, clarithromycin and metronidazole) was used from 2003-2012 ("regimen 2"). Amniotic fluid was cultured and matrix metalloproteinase-8 (MMP-8) concentrations were measured.

RESULTS

(1) The rates of intra-amniotic inflammation and intra-amniotic inflammation/infection in patients who received regimen 2 decreased during treatment from 68.8% to 52.1% and from 75% to 54.2%, respectively. In contrast, in patients who received regimen 1, the frequency of intra-amniotic inflammation and infection/inflammation increased during treatment (31.7% to 55% and 34.1% to 58.5%, respectively); and (2) intra-amniotic inflammation/infection was eradicated in 33.3% of patients who received regimen 2, but in none who received regimen 1.

CONCLUSION

The administration of ceftriaxone, clarithromycin and metronidazole was associated with a more successful eradication of intra-amniotic inflammation/infection and prevented secondary intra-amniotic inflammation/infection more frequently than an antibiotic regimen which included ampicillin and/or cephalosporins in patients with preterm PROM.

A new anti-microbial combination prolongs the latency period, reduces acute histologic chorioamnionitis as well as funisitis, and improves neonatal outcomes in preterm PROM

OBJECTIVE

Antibiotic administration is a standard practice in preterm premature rupture of membranes (PROM). Specific anti-microbial agents often include ampicillin and/or erythromycin. Anaerobes and genital mycoplasmas are frequently involved in preterm PROM, but are not adequately covered by antibiotics routinely used in clinical practice. Our objective was to compare outcomes of PROM treated with standard antibiotic administration versus a new combination more effective against these bacteria.

STUDY DESIGN

A retrospective study compared perinatal outcomes in 314 patients with PROM <34 weeks receiving anti-microbial regimen 1 (ampicillin and/or cephalosporins; n = 195, 1993-2003) versus regimen 2 (ceftriaxone, clarithromycin and metronidazole; n = 119, 2003-2012). Intra-amniotic infection/inflammation was assessed by positive amniotic fluid culture and/or an elevated amniotic fluid MMP-8 concentration (>23 ng/mL).

RESULTS

(1) Patients treated with regimen 2 had a longer median antibiotic-to-delivery interval than those with regimen 1 [median (interquartile range) 23 d (10-51 d) versus 12 d (5-52 d), p < 0.01]; (2) patients who received regimen 2 had lower rates of acute histologic chorioamnionitis (50.5% versus 66.7%, p < 0.05) and funisitis (13.9% versus 42.9%, p < 0.001) than those who had received regimen 1; (3) the rates of intra-ventricular hemorrhage (IVH) and cerebral palsy (CP) were significantly lower in patients allocated to regimen 2 than regimen 1 (IVH: 2.1% versus 19.0%, p < 0.001 and CP: 0% versus 5.7%, p < 0.05); and (4) subgroup analysis showed that regimen 2 improved perinatal outcomes in pregnancies with intra-amniotic infection/inflammation, but not in those without intra-amniotic infection/inflammation (after adjusting for gestational age and antenatal corticosteroid administration).

CONCLUSION

A new antibiotic combination consisting of ceftriaxone, clarithromycin, and metronidazole prolonged the latency period, reduced acute histologic chorioamnionitis/funisitis, and improved neonatal outcomes in patients with preterm PROM. These findings suggest that the combination of anti-microbial agents (ceftriaxone, clarithromycin, and metronidazole) may improve perinatal outcome in preterm PROM.

Sterile and microbial-associated intra-amniotic inflammation in preterm prelabor rupture of membranes

OBJECTIVE

The objectives of this study were to: (1) determine the amniotic fluid (AF) microbiology of patients with preterm prelabor rupture of membranes (PROM); and (2) examine the relationship between intra-amniotic inflammation with and without microorganisms (sterile inflammation) and adverse pregnancy outcomes in patients with preterm PROM.

METHODS

AF samples obtained from 59 women with preterm PROM were analyzed using cultivation techniques (for aerobic and anaerobic bacteria as well as genital mycoplasmas) and with broad-range polymerase chain reaction coupled with electrospray ionization mass spectrometry (PCR/ESI-MS). AF concentration of interleukin-6 (IL-6) was determined using ELISA. Results of both tests were correlated with AF IL-6 concentrations and the occurrence of adverse obstetrical/perinatal outcomes.

RESULTS

(1) PCR/ESI-MS, AF culture, and the combination of these two tests each identified microorganisms in 36% (21/59), 24% (14/59) and 41% (24/59) of women with preterm PROM, respectively; (2) the most frequent microorganisms found in the amniotic cavity were Sneathia species and Ureaplasma urealyticum; (3) the frequency of microbial-associated and sterile intra-amniotic inflammation was overall similar [ 29% (17/59)]: however, the prevalence of each differed according to the gestational age when PROM occurred; (4) the earlier the gestational age at preterm PROM, the higher the frequency of both microbial-associated and sterile intra-amniotic inflammation; (5) the intensity of the intra-amniotic inflammatory response against microorganisms is stronger when preterm PROM occurs early in pregnancy; and (6) the frequency of acute placental inflammation (histologic chorioamnionitis and/or funisitis) was significantly higher in patients with microbial-associated intra-amniotic inflammation than in those without intra-amniotic inflammation [93.3% (14/15) versus 38% (6/16); p = 0.001].

CONCLUSIONS

(1) The frequency of microorganisms in preterm PROM is 40% using both cultivation techniques and PCR/ESI-MS; (2) PCR/ESI-MS identified microorganisms in the AF of 50% more women with preterm PROM than AF culture; and (3) sterile intra-amniotic inflammation was present in 29% of these patients, and it was as or more common than microbial-associated intra-amniotic inflammation among those presenting after, but not before, 24 weeks of gestation.

Antibiotics for preterm rupture of membranes

BACKGROUND

Premature birth carries substantial neonatal morbidity and mortality. Subclinical infection is associated with preterm rupture of membranes (PROM). Prophylactic maternal antibiotic therapy might lessen infectious morbidity and delay labour, but could suppress labour without treating underlying infection.

OBJECTIVES

To evaluate the immediate and long-term effects of administering antibiotics to women with PROM before 37 weeks, on maternal infectious morbidity, neonatal morbidity and mortality, and longer-term childhood development.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 September 2013).

SELECTION CRITERIA

Randomised controlled trials comparing antibiotic administration with placebo that reported clinically relevant outcomes were included as were trials of different antibiotics. Trials in which no placebo was used were included for the outcome of perinatal death alone.

DATA COLLECTION AND ANALYSIS

We extracted data from each report without blinding of either the results or the treatments that women received. We sought unpublished data from a number of authors.

MAIN RESULTS

We included 22 trials, involving 6872 women and babies.The use of antibiotics following PROM is associated with statistically significant reductions in chorioamnionitis (average risk ratio (RR) 0.66, 95% confidence interval (CI) 0.46 to 0.96, and a reduction in the numbers of babies born within 48 hours (average RR 0.71, 95% CI 0.58 to 0.87) and seven days of randomisation (average RR 0.79, 95% CI 0.71 to 0.89). The following markers of neonatal morbidity were reduced: neonatal infection (RR 0.67, 95% CI 0.52 to 0.85), use of surfactant (RR 0.83, 95% CI 0.72 to 0.96), oxygen therapy (RR 0.88, 95% CI 0.81 to 0.96), and abnormal cerebral ultrasound scan prior to discharge from hospital (RR 0.81, 95% CI 0.68 to 0.98). Co-amoxiclav was associated with an increased risk of neonatal necrotising enterocolitis (RR 4.72, 95% CI 1.57 to 14.23).One study evaluated the children's health at seven years of age (ORACLE Children Study) and found antibiotics seemed to have little effect on the health of children.

AUTHORS' CONCLUSIONS

Routine prescription of antibiotics for women with preterm rupture of the membranes is associated with prolongation of pregnancy and improvements in a number of short-term neonatal morbidities, but no significant reduction in perinatal mortality. Despite lack of evidence of longer-term benefit in childhood, the advantages on short-term morbidities are such that we would recommend antibiotics are routinely prescribed. The antibiotic of choice is not clear but co-amoxiclav should be avoided in women due to increased risk of neonatal necrotising enterocolitis.

Antibiotic Therapy for Premature Rupture of Membranes and Preterm Labor and Effect on Fetal Outcome

In Germany almost 10 % of children are born before the end of 37th week of gestation. In at least one quarter of these cases, ascending infection of the vagina plays a causative role, particularly during the early weeks of gestation. If, in addition to the decidua, the amniotic membrane, amniotic fluid and the umbilical cord are also affected, infection not only triggers uterine contractions and premature rupture of membranes but also initiates a systemic inflammatory reaction on the part of the fetus, which can increase neonatal morbidity. Numerous studies and meta-analyses have found that antibiotic therapy prolongs pregnancy and reduces neonatal morbidity. No general benefit of antibiotic treatment was found for premature uterine contractions. But it is conceivable that a subgroup of pregnant women would benefit from antibiotic treatment. It is important to identify this subgroup of women and offer them targeted treatment. This overview summarizes the current body of evidence on antibiotic treatment for impending preterm birth and the effect on neonatal outcomes.

Antibiotics in the management of PROM and preterm labor

A significant fraction of preterm birth results from subclinical intrauterine infection. It is presumed that ascending bacterial colonization of the decidua results and either uterine contractions or membrane weakening that results in the clinical presentation of preterm labor or PROM. Those with overt infection require delivery. However, it is plausible that adjunctive antibiotic treatment during therapy for preterm labor and PROM remote from term could result in pregnancy prolongation and reductions in gestational age-dependent and infectious newborn morbidities. Data support adjunctive antibiotic treatment during conservative management of PROM remote from term. Such treatment should include broad-spectrum agents, typically intravenous therapy initially, and continue for up to 7 days if undelivered. Such treatment should be reserved for women presenting remote from term where significant improvement in neonatal outcomes can be anticipated with conservative management. Alternatively, current evidence suggests that antibiotic treatment in the setting of preterm labor with intact membranes does not consistently prolong pregnancy or improve newborn outcomes. Given this, and the concerning findings from the ORACLE II trial of antibiotics for preterm labor, this treatment should not be offered in the setting of preterm labor with intact membranes. Although one could speculate that women with preterm labor and with either a short cervical length for a positive fetal fibronectin screen might benefit from antibiotic therapy, no well-designed, randomized, controlled trials addressing this issue have been completed. Therefore, antibiotic therapy for women in preterm labor should be reserved for usual clinical indications, including suspected bacterial infections, GBS prophylaxis, and chorioamnionitis.

Antibiotics for preterm rupture of membranes

BACKGROUND

Premature birth carries substantial neonatal morbidity and mortality. Subclinical infection is associated with preterm rupture of membranes (PROM). Prophylactic maternal antibiotic therapy might lessen infectious morbidity and delay labour, but could suppress labour without treating underlying infection.

OBJECTIVES

To evaluate the immediate and long-term effects of administering antibiotics to women with PROM before 37 weeks, on maternal infectious morbidity, neonatal morbidity and mortality, and longer-term childhood development.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (29 April 2010).

SELECTION CRITERIA

Randomised controlled trials comparing antibiotic administration with placebo that reported clinically relevant outcomes were included as were trials of different antibiotics. Trials in which no placebo was used were included for the outcome of perinatal death alone.

DATA COLLECTION AND ANALYSIS

We extracted data from each report without blinding of either the results or the treatments that women received. We sought unpublished data from a number of authors.

MAIN RESULTS

We included 22 trials, involving 6800 women and babies.The use of antibiotics following PROM is associated with statistically significant reductions in chorioamnionitis (average risk ratio (RR) 0.66, 95% confidence interval (CI) 0.46 to 0.96, and a reduction in the numbers of babies born within 48 hours (average RR 0.71, 95% CI 0.58 to 0.87) and seven days of randomisation (average RR 0.79, 95% CI 0.71 to 0.89). The following markers of neonatal morbidity were reduced: neonatal infection (RR 0.67, 95% CI 0.52 to 0.85), use of surfactant (RR 0.83, 95% CI 0.72 to 0.96), oxygen therapy (RR 0.88, 95% CI 0.81 to 0.96), and abnormal cerebral ultrasound scan prior to discharge from hospital (RR 0.81, 95% CI 0.68 to 0.98). Co-amoxiclav was associated with an increased risk of neonatal necrotising enterocolitis (RR 4.72, 95% CI 1.57 to 14.23).One study evaluated the children's health at seven years of age (ORACLE Children Study) and found antibiotics seemed to have little effect on the health of children.

AUTHORS' CONCLUSIONS

The decision to prescribe antibiotics for women with PROM is not clearcut. Benefits in some short-term outcomes (prolongation of pregnancy, infection, less abnormal cerebral ultrasound before discharge from hospital) should be balanced against a lack of evidence of benefit for others, including perinatal mortality, and longer term outcomes. If antibiotics are prescribed it is unclear which would be the antibiotic of choice.Co-amoxiclav should be avoided in women at risk of preterm delivery due to increased risk of neonatal necrotising enterocolitis.

Meconium in the amniotic fluid of pregnancies complicated by preterm premature rupture of membranes is associated with early onset neonatal sepsis

OBJECTIVE

This study was to determine the significance of meconium in the amniotic fluid of pregnancies complicated by preterm premature rupture of membranes (PPROM) without labor.

METHODS

A case-control study of 31 pregnancies complicated by PPROM at 27-36 weeks gestation with meconium present (study group) and 93 pregnancies complicated by PPROM but without meconium was performed. The patients were matched for year of delivery, gestational age, race, and parity. Pregnancy and neonatal outcome variables of the 2 groups were compared.

RESULTS

The incidence of early onset neonatal sepsis was significantly increased in the study group (16.1% vs. 1.1%; P < 0.001). Similarly, chorioamnionitis (48.3% vs. 22.5%; P < 0.01), cesarean delivery for a nonreassuring fetal heart rate pattern (19.4% vs. 3.2%; P < 0.01), a 5-min Apgar score < 7 (22.5% vs. 8.6%; P < 0.05), and fetal growth retardation (FGR) (12.9% vs. 2.2%; P < 0.05) were also more common in pregnancies complicated by PPROM with meconium. The mean umbilical cord arterial pH was significantly lower in these pregnancies (7.18 +/- 0.07 vs. 7.28 +/- 0.08; P < 0.001). After controlling for confounding variables with multiple logistic regression analysis, we found that meconium in the amniotic fluid remained associated with early onset neonatal sepsis.

CONCLUSIONS

The presence of meconium in the amniotic fluid of pregnancies complicated by PPROM is associated with an increased incidence of early onset neonatal group B beta-hemolytic streptococcus (GBBS) sepsis.

Role of innate host defenses in susceptibility to early-onset neonatal sepsis

Neonatal sepsis continues to take a devastating toll globally. Although adequate to protect against invasive infection in most newborns, the distinct function of neonatal innate host defense coupled with impairments in adaptive immune responses increases the likelihood of acquiring infection early in life, with subsequent rapid dissemination and death. Unique differences exist between neonates and older populations with respect to the capacity, quantity, and quality of innate host responses to pathogens. Recent characterization of the age-dependent maturation of neonatal innate immune function has identified novel translational approaches that may lead to improved diagnostic, prophylactic, and therapeutic modalities.

Antibiotics for pre-term pre-labour rupture of membranes: prevention of neonatal deaths due to complications of pre-term birth and infection

Background In high-income countries, it is standard practice to give antibiotics to women with pre-term, pre-labour rupture of membranes (pPROM) to delay birth and reduce the risk of infection. In low and middle-income settings, where some 2 million neonatal deaths occur annually due to complications of pre-term birth or infection, many women do not receive antibiotic therapy for pPROM.

Objectives To review the evidence for and estimate the effect on neonatal mortality due to pre-term birth complications or infection, of administration of antibiotics to women with pPROM, in low and middle-income countries.

Methods We performed a systematic review to update a Cochrane review. Standardized abstraction forms were used. The quality of the evidence provided by individual studies and overall was assessed using an adapted GRADE approach.

Results Eighteen RCTs met our inclusion criteria. Most were from high-income countries and provide strong evidence that antibiotics for pPROM reduce the risk of respiratory distress syndrome [risk ratio (RR) = 0.88; confidence interval (CI) 0.80, 0.97], and early onset postnatal infection (RR = 0.61; CI 0.48, 0.77). The data are consistent with a reduction in neonatal mortality (RR = 0.90; CI 0.72, 1.12).

Conclusion Antibiotics for pPROM reduce complications due to pre-term delivery and post-natal infection in high-income settings. There is moderate quality evidence that, in low-income settings, where access to other interventions (antenatal steroids, surfactant therapy, ventilation, antibiotic therapy) may be low, antibiotics for pPROM could prevent 4% of neonatal deaths due to complications of prematurity and 8% of those due to infection.

Preterm prelabour amniorrhexis

Preterm delivery occurs in less than 10% of pregnancies but accounts for more than 60% of all neonatal deaths. Approximately one third of preterm deliveries are associated with preterm prelabour amniorrhexis and in a high proportion of such cases the underlying cause may be ascending infection from the lower genital tract. The causes of neonatal death in pregnancies with amniorrhexis are prematurity, pulmonary hypoplasia and sepsis. In the management of pregnancies with preterm prelabour amniorrhexis it is essential to distinguish between those with and without intrauterine infection. If there is no infection at presentation it is unlikely that this will develop and in such cases there is no benefit from hospitalisation, bed rest, prophylactic tocolytics or antibiotics. The group with evidence of intrauterine infection go into spontaneous labour within a few days of amniorrhexis; in this group the main determinant for the appropriate management is the gestation at amniorrhexis.

Use of antibiotics for the treatment of preterm parturition and prevention of neonatal morbidity: a metaanalysis

OBJECTIVE

We conducted a metaanalysis to determine whether antibiotics prolong pregnancy and reduce neonatal morbidity in preterm premature rupture of membranes (PPROM) and preterm labor (PTL) at 34 weeks or less.

STUDY DESIGN

Randomized trials comparing antibiotic therapy with placebo in PPROM or PTL at a gestation of 34 weeks or less were retrieved. The primary outcome was time to delivery (latency). Infant outcomes included mortality, infection, neurological abnormality, respiratory disease, and neonatal stay.

RESULTS

Antibiotics were associated with prolongation of pregnancy in PPROM (P < .01) but not PTL. Clinically diagnosed neonatal infections were reduced in both groups; there was a trend toward reduced culture-positive sepsis in PPROM. Intraventricular hemorrhage (all grades) was reduced in PPROM. Other neonatal outcomes were unaffected by antenatal antibiotics.

CONCLUSION

Antibiotics prolong pregnancy and reduce neonatal morbidity in women with PPROM at a gestation of 34 weeks or less. In PTL at a gestation of 34 weeks or less, there is little evidence of benefit from administration of antibiotics.

Prevention of preterm birth

For an infant without lethal congenital malformations there is no risk greater than to be born too early. In addition, preterm birth with its many consequences may compromise the life of the whole family. Thus, prevention of preterm birth is one of the greatest challenges in obstetrics. However, this has proven to be difficult. This difficulty is in part due to the fact that, although we know a large number of clinical factors which are know a large number of clinical factors which are associated with preterm birth, the final mechanisms triggering the onset of preterm contractions or premature rupture of the fetal membranes (PROM) have remained largely unclear. We review the prevention of preterm birth in the light of the newest data; an interested reader is also referred to other recent overviews on the same topic.

Neonatal mortality and morbidity after aggressive long-term tocolysis for preterm premature rupture of the membranes

OBJECTIVE

To test the hypothesis that predischarge morbidity and mortality are not increased for infants admitted to our neonatal intensive care unit and whose mothers had tocolysis for >48 h plus antibiotics and steroids (aggressive long-term tocolysis) after preterm premature rupture of the membranes (PPROM) as compared with gestational age-matched infants born to mothers not treated for PPROM.

METHODS

A retrospective cohort study was conducted on live preterm births (<or=36.0 weeks) admitted to the neonatal intensive care unit between January 1, 1999 and June 30, 2003, comparing singletons born to mothers with PPROM+tocolysis for >48 h (n=137, group 1) with singletons born to all other mothers matched for group-1 gestational age at delivery (n=628, group 2), excluding severe maternal complications such as insulin-dependent diabetes and preeclampsia in both groups. Primary outcome was the predischarge mortality and morbidity of the neonates.

RESULTS

In the group with post-PPROM tocolysis which lasted for 14.4+/-14.0 days with a latency of 15.3+/-15.3 days (time from PPROM to delivery) and 14.4+/-14.0 days (time from the start of tocolysis to delivery), the predischarge mortality and morbidity was not increased compared to the non-treated group. The 1- and 10-min Apgar scores of between 1 and 7 were less frequent with tocolysis (p<0.05), and oxygen use was less frequent (26.3 vs. 36.3%, p=0.03) and shorter (8.7 vs. 19.6 days, p=0.03). However, amniotic fluid infection syndrome and latency (i.e. >1 week) are the most potential predictors of the respiratory distress syndrome in addition to gestational age at delivery in pregnancies with post-PPROM tocolysis.

CONCLUSIONS

Amniotic fluid infection syndrome and a latency of >1 week achieved by aggressive post-PPROM tocolysis lessens the advantages of extended gestational age and decreased predischarge neonatal morbidity. These findings may have important implications for the clinical management of PPROM.

The NICHD-MFMU antibiotic treatment of preterm PROM study: impact of initial amniotic fluid volume on pregnancy outcome

OBJECTIVE

The purpose of this study was to evaluate the associations between measured amniotic fluid volume and outcome after preterm premature rupture of membranes (PROM).

STUDY DESIGN

This was a secondary analysis of 290 women, with singleton pregnancies, who participated in a trial of antibiotic therapy for preterm PROM at 24(0) to 32(0) weeks. Each underwent assessment of the 4 quadrant amniotic fluid index (AFI) and a maximum vertical fluid pocket (MVP) before randomization. The impact of low AFI (< 5.0 cm) and low MVP (< 2.0 cm) on latency, amnionitis, neonatal morbidity, and composite morbidity (any of death, RDS, early sepsis, stage 2-3 necrotizing enterocolitis, and/or grade 3-4 intraventricular hemorrhage) was assessed. Logistic regression controlled for confounding factors including gestational age at randomization, GBS carriage, and antibiotic study group.

RESULTS

Low AFI and low MVP were identified in 67.2% and 46.9% of women, respectively. Delivery occurred by 48 hours, 1 and 2 weeks in 32.4%, 63.5% and 81.7% of pregnancies, respectively. Both low AFI and low MVP were associated with shorter latency (P < .001), and with a higher rate of delivery at 48 hours, 1, and 2 weeks (P = .02 for each). However, neither test offered significant additional predictive value over the risk in the total population. Low AFI and low MVP were not associated with increased amnionitis. After controlling for other factors, both low MVP and low AFI were associated with shorter latency (P < or = .002), increased composite morbidity (P = .03), and increased RDS (P < or = .01), but not with increased neonatal sepsis (P = .85) or pneumonia (P = .53). Alternatively, after controlling for fluid volume, gestational age, and GBS carriage, the antibiotic study group had longer latency, and suffered less common primary outcomes and neonatal sepsis.

CONCLUSION

Oligohydramnios should not be a consideration in determining which women will be candidates for expectant management or antibiotic treatment when it is identified at initial assessment of preterm PROM remote from term.

Preterm premature rupture of membranes: diagnosis, evaluation and management strategies

Preterm premature rupture of the membranes (PPROM) is responsible for one-third of all preterm births and affects 120,000 pregnancies in the United States each year. Effective treatment relies on accurate diagnosis and is gestational age dependent. The diagnosis of PPROM is made by a combination of clinical suspicion, patient history and some simple tests. PPROM is associated with significant maternal and neonatal morbidity and mortality from infection, umbilical cord compression, placental abruption and preterm birth. Subclinical intrauterine infection has been implicated as a major aetiological factor in the pathogenesis and subsequent maternal and neonatal morbidity associated with PPROM. The frequency of positive cultures obtained by transabdominal amniocentesis at the time of presentation with PPROM in the absence of labour is 25-40%. The majority of amniotic fluid infection in the setting of PPROM does not produce the signs and symptoms traditionally used as diagnostic criteria for clinical chorioamnionitis. Any evidence of infection by amniocentesis should be considered carefully as an indication for delivery. Documentation of amniotic fluid infection in women who present with PPROM enables us to triage our therapeutic decision making rationally. In PPROM, the optimal interval for delivery occurs when the risks of immaturity are outweighed by the risks of pregnancy prolongation (infection, abruption and cord accident). Lung maturity assessment may be a useful guide when planning delivery in the 32- to 34-week interval. A gestational age approach to therapy is important and should be adjusted for each hospital's neonatal intensive care unit. Antenatal antibiotics and corticosteroid therapies have clear benefits and should be offered to all women without contraindications. During conservative management, women should be monitored closely for placental abruption, infection, labour and a non-reassuring fetal status. Women with PPROM after 32 weeks of gestation should be considered for delivery, and after 34 weeks the benefits of delivery clearly outweigh the risks.

Antibiotics for preterm rupture of the membranes: a systematic review

OBJECTIVE

We sought to evaluate the administration of antibiotics to pregnant women with preterm rupture of membranes (PROM).

DATA SOURCES

We collected data by using the Cochrane Controlled Trials Register and MEDLINE.

METHODS OF STUDY SELECTION

We included randomized controlled comparisons of antibiotic versus placebo (14 trials, 6,559 women).

TABULATION, INTEGRATION, AND RESULTS

Antibiotics were associated with a statistically significant reduction in maternal infection and chorioamnionitis. There also was a reduction in the number of infants born within 48 hours and 7 days and with the following morbidities: neonatal infection (relative risk [RR] 0.67, 95% confidence interval [CI] 0.52-0.85), positive blood culture (RR 0.75, 95% CI 0.60-0.93), use of surfactant (RR 0.83 95% CI 0.72-0.96), oxygen therapy (RR 0.88, 95% CI 0.81-0.96), and abnormal cerebral ultrasound scan before discharge from hospital (RR 0.82, 95% CI 0.68-0.99). Perinatal mortality was not significantly reduced (RR 0.91, 95% CI 0.75-1.11). A benefit was present both in trials where penicillins and erythromycin were used. Amoxicillin/clavulanate was associated with a highly significant increase in the risk of necrotizing enterocolitis (RR 4.60, 95% CI 1.98-10.72).

CONCLUSION

The administration of antibiotics after PROM is associated with a delay in delivery and a reduction in maternal and neonatal morbidity. These data support the routine use of antibiotics for women with PROM. Penicillins and erythromycin were associated with similar benefits, but erythromycin was used in larger trials and, thus, the results are more robust. Amoxicillin/clavulanate should be avoided in women at risk of preterm delivery because of the increased risk of neonatal necrotizing enterocolitis. Antibiotic administration after PROM is beneficial for both women and neonates.

An Evidence-Based Approach to the Evaluation and Treatment of Premature Rupture of Membranes: Part II

Preterm premature rupture of membranes (PPROM) occurs in 3% of pregnancies and is responsible for one third of all preterm births. In part I of this series, the definition, pathophysiology, and diagnosis of PPROM was reviewed. In this part, treatment is discussed. Adjunctive antibiotic and corticosteroid therapy has the strongest evidence for improving neonatal outcome. Treatment is gestational age-dependent and will be influenced by local neonatal intensive-care unit (NICU) survival statistics. This review presents the available evidence and grades it according to the U.S. Preventative Task Force recommendations.

LEARNING OBJECTIVES

After completion of this article, the reader should be able to summarize the data on the use of labor inhibition in the setting of PPROM, list potential antibiotics regimens that are recommended for prophylaxis in patients with PPROM, to describe the benefits of corticosteroid administration in patients with PPROM, and to outline potential management strategies for patients with PPROM based on gestational age.

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.

Duration of antibiotic therapy after preterm premature rupture of fetal membranes

OBJECTIVE

This study was undertaken to compare the efficacy of 3 days versus 7 days of ampicillin in prolonging gestation for at least 7 days in women with preterm premature rupture of membranes (PPROM).

STUDY DESIGN

We performed a randomized clinical trial comparing 3 days of ampicillin with 7 days ampicillin in patients with PPROM. Our primary outcome was the prolongation of pregnancy for at least 7 days. Secondary outcomes included rates of chorioamnionitis, postpartum endometritis, and neonatal morbidity and mortality.

RESULTS

Forty-eight patients were randomly selected. There was no statistically significant difference in the ability to achieve a 7-day latency (relative risk 0.83, 95% CI 0.51-1.38). In addition, there was no statistically significant difference in the rates of chorioamnionitis, endometritis, and our composite neonatal morbidity.

CONCLUSION

In patients with PPROM, length of antibiotic therapy does not change the rate of a 7-day latency or affect the rate of chorioamnionitis, postpartum endometritis, or neonatal morbidity.

Neutrophil granule products: can they identify subclinical chorioamnionitis in patients with preterm premature rupture of membranes?

OBJECTIVE

Our purpose was to determine whether maternal plasma levels of neutrophil granule products are elevated in patients with chorioamnionitis after preterm premature rupture of membranes (PROM).

STUDY DESIGN

Fifty-two patients between 24 and 34 weeks' gestation with preterm PROM were included. Plasma samples for defensins and lactoferrin were collected throughout latency. Fifty-two control subjects between 26 and 30 weeks' gestation were recruited for baseline levels.

RESULTS

Mean control defensin levels were compared with mean defensin levels on admission (668 ng/mL vs 5665 ng/mL, P<.01). Mean defensin levels on admission in patients without chorioamnionitis were compared with those of patients in whom histologic chorioamnionitis developed (520 ng/mL vs 9163 ng/mL, P<.01). The same relationships were not demonstrated for lactoferrin. With use a defensin value of 1500 ng/mL on admission, the sensitivity is 76% and specificity is 94% in predicting histologic chorioamnionitis.

CONCLUSIONS

Maternal plasma levels of defensins are markers of histologic chorioamnionitis in patients after preterm PROM.

What we have learned regarding antibiotic therapy for the reduction of infant morbidity after preterm premature rupture of the membranes

Preterm premature rupture of the membranes (pPROM) is responsible for approximately one third of the over 450,000 preterm births occurring in the United States annually. In this manuscript, we summarize the outcomes and analyses related to the National Institute of Child Health and Human Development Maternal Fetal Medicine Units Network (NICHD-MFMU) network multicenter trial of antibiotics to reduce infant morbidity after pPROM. Based on evident reduction in gestational age dependent and infectious infant morbidity, we provide the rationale for aggressive intravenous and oral, broad spectrum Ampicillin/Amoxicillin, and Erythromycin therapy during conservative management of pPROM before 32 weeks' gestation. We further review the histopathologic correlates to pPROM, to antibiotic treatment, and to perinatal outcome, and discuss the relationships between maternal and neonatal cytokine levels intercellular adhesion molecule, and other clinical and plasma markers regarding perinatal morbidity. The use and limitations of ultrasound and vaginally collected amniotic fluid pulmonary maturity assessment are discussed.

Antibiotics for preterm rupture of membranes

BACKGROUND

Premature birth carries substantial neonatal morbidity and mortality. One cause, associated with preterm rupture of membranes (pROM), is often subclinical infection. Maternal antibiotic therapy might lessen infectious morbidity and delay labour, but could suppress labour without treating underlying infection.

OBJECTIVES

To evaluate the immediate and long-term effects of administering antibiotics to women with pROM before 37 weeks, on maternal infectious morbidity, fetal and neonatal morbidity and mortality, and longer term childhood development.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group trials register (January 2003) and the Cochrane Controlled Trials Register (The Cochrane Library, Issue 4, 2002).

SELECTION CRITERIA

Randomised controlled trials comparing antibiotic administration with placebo that reported clinically relevant outcomes, were included. In addition, trials, in which no placebo was used, were included for the outcome of perinatal death alone.

DATA COLLECTION AND ANALYSIS

Data were extracted from each report without blinding of either the results or the treatments that women received. Unpublished data were sought from a number of authors.

MAIN RESULTS

Nineteen trials involving over 6000 women and their babies were included. The use of antibiotics following pROM is associated with a statistically significant reduction in chorioamnionitis (relative risk (RR) 0.57, 95% confidence interval (CI) 0.37 to 0.86). There was a reduction in the numbers of babies born within 48 hours (RR 0.71, 95% CI 0.58 to 0.87) and seven days of randomisation (RR 0.80, 95% CI 0.71 to 0.90). The following markers of neonatal morbidity were reduced: neonatal infection (RR 0.68, 95% CI 0.53 to 0.87), use of surfactant (RR 0.83, 95% CI 0.72 to 0.96), oxygen therapy (RR 0.88, 95% CI 0.81 to 0.96), and abnormal cerebral ultrasound scan prior to discharge from hospital (RR 0.82, 95% CI 0.68 to 0.98). Co-amoxiclav was associated with an increased risk of neonatal necrotising enterocolitis (RR 4.60, 95% CI 1.98 to 10.72).

REVIEWER'S CONCLUSIONS

Antibiotic administration following pROM is associated with a delay in delivery and a reduction in major markers of neonatal morbidity. These data support the routine use of antibiotics in pPROM. The choice as to which antibiotic would be preferred is less clear as, by necessity, fewer data are available. Co-amoxiclav should be avoided in women at risk of preterm delivery because of the increased risk of neonatal necrotising enterocolitis. From the available evidence, erythromycin would seem a better choice.

Tocolytic therapy with preterm premature rupture of membranes

Tocolytic therapy with preterm premature rupture of membranes continues to be a controversial issue. Articles focusing on potential benefits and adverse outcomes associated with tocolysis in this disease process are reviewed. Although there may be some short-term neonatal benefit, further investigation of this issue is warranted.

Antibiotics and the management of preterm premature rupture of the fetal membranes

Preterm premature rupture of membranes remains an important cause of preterm birth and neonatal morbidity and mortality. Although the underlying pathophysiology remains largely undefined, subclinical infection has been implicated both in the mechanism of membrane rupture and the resultant neonatal morbidity. The use of maternal systemic antibiotics reduces both neonatal and maternal morbidity in the expectant management of PPROM. Although concern persists over the development of resistant strains of organisms involved with neonatal sepsis, current data support the use of antibiotics in this setting. Further study is needed regarding the risks and benefits of additional tocolytic therapy or antenatal corticosteroids in the management of PPROM, and the predictors of successful and unsuccessful conservative management, and subclinical intrauterine infection. This will be helpful in the ultimate delineation of the optimal management scheme for PPROM.

Maturity testing with preterm premature rupture of the membranes

The presence or absence of fetal pulmonary maturity as assessed by amniotic fluid analysis and the role of fetal maturity tests in the management of premature rupture of the membranes are addressed. The hazards of the high falsely immature test are carefully explored. A management scheme based on the results of amniotic fluid analysis is also described.

Infection, antibiotics, and preterm delivery

The relationship between genital tract infection and preterm delivery has been established on the basis of biochemical, microbiological, and clinical evidence. In theory, pathogenic bacteria may ascend from the lower reproductive tract into the uterus, and the resulting inflammation leads to preterm labor, rupture of the membranes, and birth. A growing body of evidence suggests that preterm labor and/rupture of the membranes are triggered by micro-organisms in the genital tract and by the host response to these organisms, ie, elaboration of cytokines and proteolytic enzymes. Epidemiologic and in vitro studies do not prove a cause-and-effect relationship between infection and preterm birth. However, the preponderance of evidence indicates that treatment of asymptomatic bacteriuria and symptomatic lower genital tract infections such as bacterial vaginosis (BV), trichomoniasis, gonorrhea, and chlamydia will lower the risk of preterm delivery. Based on current evidence, pregnant women who note an abnormal vaginal discharge should be tested for BV, trichomonas, gonorrhea, and chlamydia. Those who test positive should be treated appropriately. A 3- to 7-day course of antibiotic treatment for asymptomatic bacteriuria during pregnancy is clinically indicated to reduce the risk of pyelonephritis and preterm delivery. Routine screening for chlamydia and gonorrhea should be performed for women at high risk of acquiring sexually transmitted diseases. The practice of routine screening for BV in asymptomatic women who are at low risk for preterm delivery cannot be supported based on evidence from the literature. Routine screening for asymptomatic bacteriuria during pregnancy is cost-effective, particularly in high-prevalence populations. The results of antibiotic trials for the treatment of preterm labor have been inconsistent. In the absence of reasonable evidence that antimicrobial therapy leads to significant prolongation of pregnancy in the setting of preterm labor, antibiotics should be used only for protecting the neonate from group B streptococci sepsis. They should not be used for the purpose of prolonging pregnancy. Multiple investigations have shown that, in patients with preterm premature rupture of the membranes, prophylactic antibiotics are of value in prolonging the latent period between rupture of the membranes and onset of labor and in reducing the incidence of maternal and neonatal infection. The most extensively tested effective antibiotic regimen for prophylaxis involves erythromycin alone or in combination with ampicilln. Controversy still exists regarding the appropriate length and route of antibiotic prophylaxis.

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.

Antimicrobial prevention of early-onset group B streptococcal sepsis: estimates of risk reduction based on a critical literature review

OBJECTIVE

To identify interventions that reduce the attack rate for early-onset group B streptococcal (GBS) sepsis in neonates.

STUDY DESIGN

Literature review and reanalysis of published data.

RESULTS

The rate of early-onset GBS sepsis in high-risk neonates can be reduced by administration of antibiotics. Treatment during pregnancy (antepartum prophylaxis) fails to reduce maternal GBS colonization at delivery. With the administration of intravenous ampicillin, the risk of early-onset infection in infants born to women with preterm premature rupture of membranes is reduced by 56% and the risk of GBS infection is reduced by 36%; addition of gentamicin may increase the efficacy of ampicillin. Treatment of women with chorioamnionitis with ampicillin and gentamicin during labor reduces the likelihood of neonatal sepsis by 82% and reduces the likelihood of GBS infection by 86%. Universal administration of penicillin to neonates shortly after birth (postpartum prophylaxis) reduces the early-onset GBS attack rate by 68% but is associated with a 40% increase in overall mortality and therefore is contraindicated. Intrapartum prophylaxis, alone or combined with postnatal prophylaxis for the infants, reduces the early-onset GBS attack rate by 80% or 95%, respectively.

CONCLUSIONS

Women with chorioamnionitis or premature rupture of membranes and their infants should be treated with intravenous ampicillin and gentamicin. Intrapartum antimicrobial prophylaxis may be appropriate for other women whose infants are at increased but less extreme risk, and supplemental postpartum prophylaxis may be indicated for some of their infants. Selection of appropriate candidates and prophylaxis strategies requires careful consideration of costs and benefits for each patient. group B streptococcus, neonatal sepsis, early-onset sepsis, prevention, prophylaxis.

Recent advances in the pathophysiology and management of preterm premature rupture of the fetal membranes

During the past few years, meaningful progress has been achieved in our understanding of the pathophysiology of preterm premature rupture of membranes. In addition, more evidence has been presented in favor of induction and delivery for rupture between 34 and 37 weeks and expectant management for rupture before 34 weeks. New approaches are being suggested to complement expectant management. The purpose of this article is to review this recent information about the pathophysiology and management of women with preterm premature rupture of membranes.

Maternal and neonatal infection rates with three different protocols for prevention of group B streptococcal disease

OBJECTIVES

We compared maternal and neonatal infection rates under 3 different group B streptococcal prevention strategies and also evaluated reasons for each protocol's failures in preventing neonatal disease.

STUDY DESIGN

Women who were delivered at our center from August 1, 1991, through April 30, 1998, were managed by 1 of 3 protocols for prevention of early-onset neonatal group B streptococcal infection: a selective screening protocol, The American College of Obstetricians and Gynecologists protocol, and the Centers for Disease Control and Prevention-recommended universal screening strategy. We compared maternal infection rates and neonatal group B streptococcal infection rates under each protocol. We also compared reasons for each protocol's failures in preventing neonatal infection.

RESULTS

Clinical chorioamnionitis rates were 7.4% with selective screening, 7.7% under The American College of Obstetricians and Gynecologists' protocol, and 5.2% with universal screening (relative risk 0.7, 95% confidence interval 0.6-0.8). Endometritis rates were 4.0% with selective screening, 4.6% with The American College of Obstetricians and Gynecologists protocol, and 2. 8% with universal screening (relative risk 0.7, 95% confidence interval 0.6-0.8). Overall neonatal group B streptococcal infection rates were lower under the 2 more recent strategies, but not significantly so. Despite the ability of universal screening to find more women at risk for group B streptococcal transmission, half of the neonatal infections under this protocol occurred when the mothers were not considered candidates for prophylaxis.

CONCLUSIONS

The Centers for Disease Control and Prevention-endorsed universal screening strategy for group B streptococcal infection prevention was associated with significantly lower rates of clinical chorioamnionitis and endometritis than were the other strategies. We were unable to document statistically significant improvement in neonatal outcome under the universal screening protocol.

Management of preterm premature rupture of the membranes

In many cases, the management of preterm PROM will be dictated by the presence of advanced labor, intrauterine infection, placental abruption, or nonreassuring fetal testing. These patients should be delivered expeditiously, with group B streptococcus prophylaxis given where possible, and cesarean delivery reserved for routine obstetric indications. The stable patient with PPROM and documented fetal pulmonary maturity is best treated by early induction. Alternatively, the patient with PPROM remote from term can benefit from conservative treatment. Adjunctive antibiotic treatment and serial evaluation of maternal and fetal well-being offer significant potential for the reduction of perinatal morbidity. Although corticosteroid and tocolytic administration remain controversial, there is a theoretical benefit to their administration, particularly if concurrent antibiotic treatment is given to treat subclinical intrauterine infection.

Antibiotic therapy in preterm premature rupture of membranes

Good quality evidence supports the use of antibiotic therapy in women with preterm PROM for whom expectant management is planned. The best evidence supports the choice of an extended-spectrum agent or combination administered intravenously for 2 days followed by an extended spectrum or combination of oral agents for several more days. Despite the effectiveness of antimicrobial therapy in this setting, the potential risks of systemic antibiotic administration, such as allergic reactions, overgrowth of commensal organisms, and emergence of resistant pathogens, much always be kept in mind. Nevertheless, in the majority of cases, assuming the patient is a good candidate for expectant management, the benefits of antibiotic therapy outweigh the risks.

Potential consequences of widespread antepartal use of ampicillin

OBJECTIVE

Recommendations for the use of antenatal antibiotics in obstetrics have increased in the past few years, especially for prophylaxis against group B streptococci, for prolongation of the latency time in patients with preterm premature rupture of the membranes, and as an adjuvant treatment in preterm labor. Our objective was to determine whether the use of antenatal ampicillin affects the incidence of and resistance of early-onset neonatal sepsis with organisms other than group B streptococci.

STUDY DESIGN

A prospective cohort study was performed between January 1, 1991, and December 31, 1996. Every case of blood culture-proven neonatal sepsis was prospectively surveyed. The type of bacteria isolated, drug resistance, antenatal antibiotic use and treatment indication, gestational age at delivery, and other antenatal and outcome variables were gathered. Early-onset neonatal sepsis was defined as disease onset within 7 days after birth.

RESULTS

A total of 42 cases of early-onset neonatal sepsis among 29,897 neonates delivered were found during the 6-year period. Of these, 15 cases were due to group B streptococci and 27 were the result of non-group B streptococcal organisms (21 gram-negative rods and 6 gram-positive cocci). Among the 27 non-group B streptococcal cases, 15 mothers had received antenatal ampicillin and 13 of the 15 bacterial isolates from these neonates (87%) were resistant to ampicillin, versus only 2 ampicillin-resistant isolates (17%) among the 12 cases in which no antenatal antibiotics were administered (P = .0004). Of the 15 mothers who were treated with ampicillin, 13 received more than 1 dose. In evaluating each year of the study, the overall administration of antibiotics to pregnant women in the antenatal period increased from <10% in 1991 to 16.9% in 1996. The incidence of early-onset neonatal sepsis with group B streptococci decreased during this time, whereas the incidence of early-onset sepsis with non-group B streptococcal organisms, especially Escherichia coli, increased.

CONCLUSIONS

The increased administration of antenatal ampicillin to pregnant women may be responsible for the increased incidence of early-onset neonatal sepsis with non-group B streptococcal organisms that are resistant to ampicillin. At this time penicillin G, rather than ampicillin, is therefore recommended for prophylaxis against group B streptococci. In addition, future studies are needed to determine whether alternate approaches, such as immunotherapy or vaginal washing, could be of benefit.

Antibiotic therapy for preterm premature rupture of membranes

Antibiotic treatment of the patient with preterm premature rupture of membranes remote from term significantly prolongs pregnancy and reduces amnionitis without increasing the risk of cesarean delivery. Antibiotic treatment reduces perinatal infectious morbidity including neonatal sepsis, GBS sepsis, and pneumonia. Stratified analysis of the currently available prospective trials also demonstrates a significant reduction in gestational-dependent morbidity, specifically respiratory distress and intraventricular hemorrhage with treatment. This is supported by a reduction in composite infant morbidity and other gestational age-dependent morbidities in the NICHD-MFMU trial. Although the optimal treatment regimen has not been determined, limited duration broad spectrum antibiotic treatment is justified in the setting of conservative management of pPROM remote from term. The patient with pPROM and documented pulmonary maturity near term may benefit more from expeditious delivery than from expectant management with antibiotics.

Concomitant use of glucocorticoids: a comparison of two metaanalyses on antibiotic treatment in preterm premature rupture of membranes

OBJECTIVE

This study was performed to investigate whether the demonstrated beneficial effects of antibiotics on maternal and neonatal morbidity are altered when glucocorticoids are part of the treatment of preterm premature rupture of membranes.

STUDY DESIGN

We performed a metaanalysis of five published, randomized trials of antibiotic treatment in preterm premature rupture of membranes in which glucocorticoids were used as additional treatments and compared the results with those of a previously published metaanalysis of antibiotic treatment in preterm premature rupture of membranes, which excluded studies with concomitant glucocorticoids. Primary outcomes included chorioamnionitis, postpartum endometritis, neonatal sepsis, respiratory distress syndrome, intraventricular hemorrhage, necrotizing enterocolitis, and neonatal mortality. A logistic regression analysis was performed to test whether glucocorticoids significantly influenced the effect of antibiotic treatment.

RESULTS

Among the 509 patients from five trials on antibiotic and glucocorticoid treatment published between 1986 and 1993 antibiotic therapy did not show any significant effect on any of the outcomes analyzed. In contrast, antibiotic therapy without concomitant use of glucocorticoids significantly reduced the odds of chorioamnionitis, postpartum endometritis, neonatal sepsis, and intraventricular hemorrhage by 62%, 50%, 68%, and 50%, respectively. The logistic regression analysis showed that glucocorticoids significantly diminished the effect of antibiotic treatment on chorioamnionitis and neonatal sepsis.

CONCLUSION

Glucocorticoids appear to diminish the beneficial effects of antibiotics in the treatment of preterm premature rupture of membranes. A careful selection of patients who are likely to benefit from both therapies is therefore recommended.