Antibiotics and preterm labor

In summary, a definite association has been demonstrated between preterm labor and genital tract infection. Conclusions regarding the true benefits of antibiotics as adjunctive therapy in treatment of preterm labor are inconsistent. Whereas some of the studies were able to demonstrate significant prolongation of pregnancy, no consistent reduction in either maternal or neonatal morbidity has been demonstrated. However, because the actual incidental morbidity rate is low in the populations studied, the power of this finding is also low. The potential risks for using antimicrobials has yet to be adequately addressed. It has been shown that bacterial resistance can develop when antibiotics are used without specific aim or when a specific bacteria is undertreated. It has been recently shown that prenatal and intrapartum antibiotic use is associated with an increased risk for antibiotic resistant neonatal sepsis if infection occurs. Because of these reasons, we discourage the administration of antibiotic treatment to women in preterm labor for the purpose of pregnancy prolongations. Treatment should be directed towards those with specific indications for treatment (e.g., intrapartum, group B streptococci prophylaxis, urinary tract infection, etc). The primary flaw in these many evaluations of preterm labor is the true incidence of preterm birth. The clinical diagnosis of preterm labor is a difficult one. Approximately one-half of those individuals with preterm contractions will not deliver until term. So, the use of antibiotics for all women in idiopathic preterm labor is destined to treat many women who are unlikely to benefit. If we were able to truly identify those who were in "true" labor, perhaps we could be more selective in determining who may benefit from antibiotics. Biochemical markers such as onco-fetal fibronectin could well-be a helpful marker. Goldberg et al evaluated FFN in vaginal and cervical secretions while attempting to better-predict who would have upper genital tract infection. In this large, multicenter trial, patients were tested for FFN every 2 weeks from 23 to 30 weeks gestation. In those patients who proceeded to deliver before 32 weeks gestation, increased levels of cervical FFN (> 50 ng/ml) were identified in approximately one-quarter. Fetal fibronectin was positive in 4% of their samples and was found to be twice as likely in one with bacterial vaginosis. They showed that the presence of increased FFN was associated with upper genital tract infection (clinical and histologic chorioamnionitis) as a main reason for preterm labor and delivery (increased risk 16-20-fold). Those with increased FFN levels were also shown to have an increased incidence of neonatal sepsis as well. Peaceman et al used FFN to attempt to identify those at risk for preterm delivery among women with contractions between 24 and 34 6/7 weeks gestation. Those with negative FFN were less likely to deliver within 7 days of the test. The negative predictive value was 99.7%, suggesting that this test may be helpful in identifying women who would not benefit from antibiotic treatment. However, if in the absence of prospective clinical trials demonstrating the efficacy of this approach, we discourage the use of FFN screening for this indication.

Expanded-spectrum antibiotics with preterm premature rupture of membranes

OBJECTIVE

To compare maternal infection rates, neonatal sepsis rates, and bacterial resistance patterns in cases of neonatal sepsis for three antibiotic protocols for women with preterm premature rupture of membranes (PROM).

METHODS

From January 1, 1988 to February 28, 1998, women with preterm PROM not requiring immediate delivery were treated according to one of three antibiotic protocols. During three distinct periods, patients received no antibiotics, intravenous ampicillin for 48 hours followed by oral amoxicillin, or intravenous ticarcillin-clavulanic acid for 48 hours followed by oral amoxicillin-clavulanic acid. Rates of chorioamnionitis, endometritis, and neonatal sepsis were compared, as were antimicrobial resistance patterns. Statistical analysis was done using chi(2) analysis, Fisher exact test, and the log-likelihood ratio test. The Bonferroni correction was used for multiple comparisons.

RESULTS

During the three periods, preterm PROM was diagnosed in 1695 women. The incidence of endometritis was lower during the third (5.3%) compared with the first (15.1%, P <.001) and second (11.6%, P <.001) protocols. Chorioamnionitis rates were 13.6%, 12.7%, and 15.6% (P =.34) for the first, second, and third periods, respectively, and neonatal sepsis rates were 2.2%, 0.6%, and 1.1% (P =.08), respectively. Neonatal sepsis with gram-negative (P =.02) and ampicillin-resistant (P =.04) organisms was more likely when mothers received antepartum ampicillin or ticarcillin-clavulanic acid.

CONCLUSION

Antibiotic therapy for patients with preterm PROM was associated with a decrease in the rate of endometritis and a trend toward less neonatal sepsis but an increase in the proportion of gram-negative and ampicillin-resistant organisms causing neonatal sepsis.

Amnioinfusion for umbilical cord compression in labour

BACKGROUND

Amnioinfusion aims to prevent or relieve umbilical cord compression during labour by infusing a solution into the uterine cavity.

OBJECTIVES

The objective of this review was to assess the effects of amnioinfusion on maternal and perinatal outcome for potential or suspected umbilical cord compression or potential amnionitis.

SEARCH STRATEGY

The Cochrane Pregnancy and Childbirth Group trials register and the Cochrane Controlled Trials Register were searched.

SELECTION CRITERIA

Randomised trials of amnioinfusion compared with no amnioinfusion in women with babies at risk of umbilical cord compression; and women at risk of intrauterine infection.

DATA COLLECTION AND ANALYSIS

Eligibility and trial quality were assessed by the reviewer.

MAIN RESULTS

Twelve studies were included. Transcervical amnioinfusion for potential or suspected umbilical cord compression was associated with the following reductions: fetal heart rate decelerations (relative risk 0.54, 95% confidence interval 0.43 to 0.68); caesarean section for suspected fetal distress (relative risk 0.35, 95% confidence interval 0.24 to 0.52); neonatal hospital stay greater than 3 days (relative risk 0.40, 95% confidence interval 0. 26 to 0.62); maternal hospital stay greater than 3 days (relative risk 0.46, 95% 0.29 to 0.74). Transabdominal amnioinfusion showed similar results. Transcervical amnioinfusion to prevent infection in women with membranes ruptured for more than 6 hours was associated with a reduction in puerperal infection (relative risk 0.50, 95% confidence interval 0.26 to 0.97).

REVIEWER'S CONCLUSIONS

Amnioinfusion appears to reduce the occurrence of variable heart rate decelerations and lower the use of caesarean section. However the studies were done in settings where fetal distress was not confirmed by fetal blood sampling. The results may therefore only be relevant where caesarean sections are commonly done for abnormal fetal heart rate alone. The trials reviewed are too small to address the possibility of rare but serious maternal adverse effects of amnioinfusion.

Group B streptococcus: to culture or not to culture?

OBJECTIVE

To determine if universal Group B Streptococcus (GBS) culturing and antibiotic prophylaxis of obstetric patients decreased the incidence of neonatal early-onset GBS sepsis and mortality and maternal chorioamnionitis.

STUDY DESIGN

A time series observational study was conducted to compare the cohort of all obstetric patients delivering at the University of Chicago neonatal center from January 1989 through December 1993, before a GBS surveillance policy existed, with the cohort delivering January 1994 through December 1996, after initiation of a GBS policy. Included in the policy were universal GBS cultures at 28 weeks' gestation, antibiotic prophylaxis at the time of labor for all those with positive cultures and for all with risk factors of preterm delivery, preterm premature rupture of membranes, prolonged rupture of membranes greater than 18 hours, and a previous child affected by GBS or maternal fever in labor. Predictor variables were GBS culturing and antibiotic usage; outcome variables were incidence of GBS sepsis and mortality in the neonates and maternal chorioamnionitis. chi-squared and Fisher exact analyses were used with p < 0.05 being significant.

RESULTS

Before the GBS policy, there were 16,272 deliveries with a 2.24/1000 deliveries rate of early-onset GBS sepsis (n = 35); after initiating the GBS policy, 9130 deliveries occurred with an early-onset GBS sepsis rate of 2.29/1000 (n = 20). Early-onset GBS sepsis case fatality rates before and after initiation of the policy were 14.3% and 0%, respectively (p = 0.09). Antibiotic use almost doubled (relative risk = 1.84; confidence interval, 1.74 to 1.93, p < 0.001) over the two time periods, and the relative risk of chorioamnionitis decreased to 0.95 (confidence interval, 0.73 to 0.99, p = 0.04).

CONCLUSION

Despite universal GBS culturing and very liberal use of antibiotics in labor, we were unable to effect a statistically significant change in the rate of early-onset GBS sepsis or mortality, and there was only a slightly decreased chorioamnionitis rate.

Management of cervical cerclage after preterm premature rupture of membranes

The optimal management of preterm premature rupture of membranes (PPROM) in a patient with a cerclage is controversial. The issues are whether the latency period between rupture of membranes and delivery is decreased if the cerclage is removed and whether there is an increased rate of maternal or neonatal infection if the cerclage is kept in place. The data are sparse in directing management of women with prophylactic cerclages placed earlier in their pregnancies who rupture membranes. Latency seems to be increased if the cerclage is kept in place, but maternal and neonatal infectious morbidity is increased also. In women at early gestational ages, keeping the cerclage in place may be warranted until labor ensues. In more advanced gestations, it seems preferable to immediately remove the cerclage upon diagnosis of PPROM.

Prophylactic cefazolin in amnioinfusions administered for meconium-stained amniotic fluid

OBJECTIVE

To determine if amnioinfusion with an antibiotic solution decreased the rate of clinical chorioamnionitis and puerperal endometritis in patients with meconium-stained amniotic fluid.

METHODS

Patients in labor at 36 weeks of gestation or greater with singleton pregnancies and meconium-stained amniotic fluid were randomized to receive either cefazolin, 1 g/1,000 mL, of normal saline (n = 90) or normal saline (n = 93) amnioinfusion. Rates of clinically diagnosed chorioamnionitis and endometritis and of suspected and culture-proven neonatal infection were determined.

RESULTS

Between the study and control groups, the incidences of clinical chorioamnionitis (7.8% vs. 8.6%), endometritis (2.4% vs. 3.5%), aggregate intrauterine infection (10.0% vs. 11.8%), suspected neonatal infection (17.8% vs. 21.5%), and proven neonatal infection (0.0% vs. 2.2%) were not significantly different.

CONCLUSIONS

Prophylactic use of cefazolin in amnioinfusions did not significantly reduce rates of maternal or neonatal infection in patients with meconium-stained amniotic fluid.

Prophylactic cefazolin in amnioinfusions administered for meconium-stained amniotic fluid

OBJECTIVE

To determine if amnioinfusion with an antibiotic solution decreased the rate of clinical chorioamnionitis and puerperal endometritis in patients with meconium-stained amniotic fluid.

METHODS

Patients in labor at 36 weeks of gestation or greater with singleton pregnancies and meconium-stained amniotic fluid were randomized to receive either cefazolin, 1 g/1,000 mL, of normal saline (n = 90) or normal saline (n = 93) amnioinfusion. Rates of clinically diagnosed chorioamnionitis and endometritis and of suspected and culture-proven neonatal infection were determined.

RESULTS

Between the study and control groups, the incidences of clinical chorioamnionitis (7.8% vs. 8.6%), endometritis (2.4% vs. 3.5%), aggregate intrauterine infection (10.0% vs. 11.8%), suspected neonatal infection (17.8% vs. 21.5%), and proven neonatal infection (0.0% vs. 2.2%) were not significantly different.

CONCLUSIONS

Prophylactic use of cefazolin in amnioinfusions did not significantly reduce rates of maternal or neonatal infection in patients with meconium-stained amniotic fluid.

A review of randomized clinical trials of antibiotic therapy in preterm premature rupture of the membranes

Rupture of membranes before 37 completed weeks of gestation, and before the onset of contractions occurs among 2-3% of pregnancies, and in about 30%-40% of women who deliver preterm. It is known as preterm premature rupture of membranes (PPROM) and is associated with maternal and neonatal morbidity. It has been postulated that antibiotic therapy may significantly decrease the complications associated with infection. The aim of the present review is to summarize the available data about the value of antibiotic therapy in PPROM.

A review of the role of trials of the use of antibiotics in women with preterm labor and intact membranes

This updated review addresses the administration of antibiotics in women presenting with preterm labor and intact membranes as well as with bacterial vaginosis. 11 randomized controlled trials dealing with this question have been published since 1986. The results are disappointing. The probable reasons are the small number of patients in the different studies and universal use of antibiotics without performing amniocentesis to isolate the organisms involved.

The role of antibiotic therapy in the prevention of prematurity

Prematurity is the leading cause of perinatal morbidity and mortality in the industrial world, occurring in 4% to 9% of all deliveries, a rate that has remained unchanged during the past decades. Despite the relative minority of obstetric patients affected by this problem, prematurity is responsible for approximately 70% to 80% of perinatal morbidity and mortality corrected for congenital anomalies. To date, treatment modalities (tocolysis) that have been applied to patients who have preterm labor (PTL) and preterm premature rupture of membranes have been found to be of limited value in reducing both the rate of prematurity and of perinatal mortality and morbidity. A possible explanation for this failure in prevention of prematurity can be attributed to the poor understanding of the mechanisms of parturition in general and the pathophysiology of PTL in particular.

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.

Administration of antibiotics to patients with rupture of membranes at term: a prospective, randomized, multicentric study. Collaborative Group on PROM

OBJECTIVE

To assess whether antibiotic administration changes the rate of materno-fetal infectious morbidity in premature rupture of membranes occurring later than 35 weeks of gestation.

METHODS

A prospective, randomized and multicentric study in the Perinatology Units of eleven hospitals in Spain. Women were randomized to either antibiotic administration or control group. All were induced, if labor had not started spontaneously after 12 hours of ruptured membranes. Main outcome measures were maternal infection (chorioamnionitis and endometritis) and neonatal infectious morbidity (neonatal sepsis, meningitis and bronchopneumonia).

RESULTS

Seven hundred and thirty-three patients were enrolled in the study, 371 in the antibiotics group and 362 in the control group. The incidence of chorioamnionitis and puerperal endometritis were reduced but the differences are statistically nonsignificant. However, the incidence of neonatal sepsis was significantly lower in newborns to mothers who had received antibiotics, 1 vs. 7 cases (Fisher's exact test, p<0.007).

CONCLUSION

The study strongly suggests that prophylactic use of antibiotics in premature rupture of membranes occurring at 36 or more weeks of gestation reduces the risk of neonatal sepsis and probably maternal endometritis.

Premature rupture of membranes at 34 to 37 weeks' gestation: aggressive versus conservative management

OBJECTIVE

Our purpose was to compare induction of labor with preterm rupture of membranes between 34 and 37 weeks' gestation with expectant management.

STUDY DESIGN

In this prospective investigation 120 gravid women at > or = 34 weeks 0 days and < 36 weeks 6 days of gestation were randomized to receive oxytocin induction (n = 57) or observation (n = 63).

RESULTS

Estimated gestational age at rupture of membranes (34.3 +/- 1.4 weeks vs 34.5 +/- 1.4 weeks) and ultrasonographically estimated fetal weight (2230 +/- 321 gm vs 2297 +/- 365 gm) were equivalent between groups (not significant). Chorioamnionitis occurred more often (16% vs 2%, p = 0.007), and maternal hospital stay (5.2 +/- 6.8 days vs 2.6 +/- 1.6 days, p = 0.006) was significantly longer in the control group. Neonatal sepsis was also more common in the observation group (n = 3) than among induction patients (n = 0), but the difference was not statistically significant.

CONCLUSION

Aggressive management of preterm premature rupture of the membranes at > or = 34 weeks 0 days of gestation by induction of labor is safe for the infant in our population and avoids maternal-neonatal infectious complications.

Preterm premature rupture of membranes: aggressive tocolysis versus expectant management

The objective of our study is to determine whether aggressive tocolysis in patients with preterm premature rupture of membranes between 24 and 34 weeks gestation improves neonatal outcome. Patients with documented preterm premature rupture of membranes between 24 and 34 weeks gestation were prospectively randomized to group I, aggressive tocolysis with intravenous magnesium sulfate, or to group II, no tocolysis. The lecithin/sphingomyelin ratio was determined upon hospital admission and every 48-96 hours until delivery. Both groups received weekly steroids and antibiotics pending culture results and were promptly delivered when chorioamnionitis, fetal stress, or an Lecithin/sphingomyelin ratio of > or = 2.0 occurred. The study group involved 145 patients. No statistically significant differences between groups I (n = 78) and II (n = 67) were observed regarding demographic characteristics, gestational age at enrollment or at delivery, latency, development of clinical chorioamnionitis, birth weight, number of days in neonatal intensive care unit, days on oxygen or ventilatory support, frequency of hyaline membrane disease, necrotizing enterocolitis, intraventricular hemorrhage, neonatal sepsis, or neonatal mortality. Our data suggest that tocolysis in patients with preterm premature rupture of membranes does not significantly improve perinatal outcome.

Interleukin-8 level in maternal serum as a marker for screening of histological chorioamnionitis at term

OBJECTIVE

To establish a clinical method for immediate diagnosis of histological chorioamnionitis, by maternal blood sampling at term.

METHOD

The sera of 22 mothers with chorioamnionitis and 81 mothers without chorioamnionitis at term delivery were collected. The serum levels of cytokines including interleukin-1 alpha (IL-1 alpha), interleukin-1 beta (IL-1 beta), tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6) and interleukin-8 (IL-8) were titered and other conventional markers such as white blood cell and CRP were measured simultaneously. Chorioamnionitis was histopathologically confirmed after delivery.

RESULT

The sera of mothers with histological chorioamnionitis showed a significant increase in IL-8 titer, but not in those of other cytokines or conventional markers, compared with those without chorioamnionitis. A positive correlation was observed between maternal and cord serum IL-8 levels. Maternal IL-8 showed the highest predictive value for diagnosis of histological chorioamnionitis.

CONCLUSION

Measurement of maternal IL-8 is useful for rapid prenatal screening of histological chorioamnionitis at term.

The efficacy of prophylactic erythromycin in preventing vertical transmission of Ureaplasma urealyticum

To determine if prophylactic erythromycin alters the vertical transmission rate of Ureaplasma urealyticum. Randomized prospective study of 51 singleton pregnancies between 22 and 35 weeks' gestation with preterm premature rupture of membranes or preterm labor. Patients received oral erythromycin for 7 days in addition to routine prophylactic intravenous ampicillin or ampicillin alone. Lower genital colonization with U. urealyticum was 33 of 51 (65%). Vertical transmission of U. urealyticum was 25% (3 of 12) in the erythromycin group and 4 of 17 (24%) for the controls. The average interval from randomization to delivery was 303.5 hr in the erythromycin group and 70.9 hr for controls (p = 0.04). Although not statistically significant, histologic chorioamnionitis in patients colonized with Ureaplasma was lower in the erythromycin group (3 of 12, 25%) compared to the controls (10 of 17, 59%). Prophylactic erythromycin does not decrease vertical transmission of Ureaplasma. It may decrease the incidence of histologic chorioamnionitis and increase the latency period.

Antenatal steroids and intraventricular hemorrhage after premature rupture of membranes at 24-28 weeks' gestation

To determine whether antenatal corticosteroid administration after midtrimester premature rupture of membranes (PROM) reduces the incidence or severity of neonatal intraventricular hemorrhage, we identified a cohort of infants delivered between 24 to 28 weeks gestation (n = 75) by mothers with PROM. Information was obtained from a computerized database (n = 3716) of all newborns admitted to the neonatal intensive care unit at a single medical center from 1991 to 1996. We reviewed records of each mother-infant pair to determine antenatal corticosteroid administration, presence, and severity of neonatal intraventricular hemorrhage, and frequency of infectious complications. Using a logistic regression model, antenatal corticosteroid administration was associated with a significantly reduced risk of severe (grade 3-4) intraventricular hemorrhage (0.1 odds ratio, 0.006-0.57, 95% confidence interval), but not a reduced incidence of intraventricular hemorrhage (grade 1-4, 0.4 odds ratio, 0.12-1.05, 95% confidence interval).

Chlorhexidine vaginal irrigation for the prevention of peripartal infection: a placebo-controlled randomized clinical trial

OBJECTIVE

Our purpose was to determine whether chlorhexidine vaginal irrigation prevents maternal peripartal infection.

STUDY DESIGN

A double-blinded, placebo-controlled, randomized trial was performed. Single 200 ml irrigations of either 0.2% chlorhexidine solution or sterile water placebo were given in active labor or before planned cesarean delivery. The primary outcome measure was the combined rate of chorioamnionitis and endometritis (which were mutually exclusive diagnoses).

RESULTS

A total of 1024 patients were enrolled: 508 in the chlorhexidine group and 516 in the placebo group. The two groups were generally well balanced on important clinical factors but differed (p < 0.05) in rates of nulliparity (chlorhexidine 42%, placebo 52%), intrauterine pressure catheter usage (chlorhexidine 65%, placebo 72%), and presence of meconium (chlorhexidine 17%, placebo 22%). There were no recognized adverse maternal or neonatal reactions to irrigation. Rates of infection (chorioamnionitis + endometritis) did not differ significantly between the groups, chlorhexidine 10% versus placebo 13% (relative risk 0.8, 95% confidence interval 0.5 to 1.1). Stratified and logistic regression analyses supported the primary univariate analysis. Neonatal outcomes, including sepsis rates of 0.4%, were equivalent for the groups.

CONCLUSION

As used in this trial, chlorhexidine lacked efficacy in the prevention of maternal peripartal infection.

[Incidence of inflammatory placental changes in threatened premature labor with and without additional antibiotic therapy]

Considering the causal association of silent intrauterine infection and prematurity we investigated the possible effect of adjuvant antibiotic treatment of women with preterm labour on the appearance of inflammatory placental lesions. 140 patients with preterm labour in the 30 + 2 week of gestation (median; range: 17 + 2-34 + 6) without premature rupture of the membranes and detection of facultative-pathogenic micro-organisms in the vagina and/or in the canal of the cervix were enrolled in the study. 74 women were treated vaginally (polyvidone-iodine) in addition to intravenous tocolysis, 66 women were given ampicillin, cefotiam or erythromycin intravenously. After delivery the placentas were examined histologically and the frequency of inflammatory lesions was evaluated by use of 4 scores of classification. For statistical analysis the Fisher Exact- and the Wilcoxon Rank Sum Test were used. We found no differences concerning amnamnestic and perinatal parameters comparing the 2 groups of patients. With only one of the histological scores used (according to Salafia et al. [18]) we found a higher frequency of inflammatory placental lesion in the antibiotic treated group (12/66) in comparison to the vaginal treated group (4/74). Fifty patients of the antibiotics' group received the antibiotic during the last 10 days before birth. No differences in the frequency of inflammatory placental lesions were detectable in these patients when compared with the local treated group. However, we found a lower prolongation of gestation (calculated from the day of admission to the day of delivery, median: 7; range: 1-92 days) and a lower gestational age at delivery (median: 33 + 0; range: 22 + 2-39 + 6 weeks) in the patients receiving antibiotics during the last 10 days before birth in comparison to the local treated women (22; 1-138 days and 35 + 0; 23 + 4-41 + 5 weeks, respectively). There is the same incidence of inflammatory placental lesions in patients with preterm labour and facultative-pathogenic micro-organisms in the vagina and/or in the canal of the cervix who received adjuvant antibiotic treatment during pregnancy compared with patients who were treated vaginally with polyvidone-iodine.

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

OBJECTIVE

To estimate the effect of prophylactic antibiotics on neonatal mortality and morbidity in patients with preterm labor, based on a meta-analysis of seven published randomized clinical trials.

DATA SOURCES

We searched 18 medical data bases, including MEDLINE from 1964 and EMBASE from 1974, to identify all literature included under preterm or premature labor and antibiotics. We scanned all abstracts from the computer printouts, the retrieved full-text reports, the references from each retrieved report, and review articles to determine whether studies met our inclusion criteria.

METHODS OF STUDY SELECTION

The following criteria were used to select studies for inclusion: article-original published report written in English; study design-randomized controlled trial; population-patients with preterm labor, defined as labor before 37 weeks' gestation; intervention-antibiotic treatment; and one or more of the following outcomes-neonatal mortality, sepsis, pneumonia, respiratory distress syndrome, intraventricular hemorrhage, and necrotizing enterocolitis.

TABULATION, INTEGRATION AND RESULTS

We analyzed study patients and methods, and abstracted quantitative outcome data. For each outcome, both odds ratio (OR) and 95% confidence interval (CI) were calculated. Seven trials, published between 1989 and 1995 included a total of 795 patients. Adjunctive antibiotic therapy appeared to reduce the risk of pneumonia (OR 0.45, 95% CI 0.12-1.72) and necrotizing enterocolitis (OR 0.38, 95% CI 0.14-1.08) and to increase the risk of neonatal mortality (OR 3.25, 95% CI 0.93-11.38), but it had no effect on neonatal sepsis (OR 0.98, 95% CI 0.34-2.83), respiratory distress syndrome (OR 0.93, 95% CI 0.54-1.87), and intraventricular hemorrhage (OR 1.01, 95% CI 0.20-5.10). None of the effects observed reached a significance level of P < .05.

CONCLUSION

The results of this meta-analysis do not support the routine use of adjunctive antibiotic treatment in patients with preterm labor diagnosed on the basis of subjective uterine contractions and the resulting cervical changes.

Premature rupture of membranes in the second trimester

Spontaneous rupture of membranes during the second trimester presents difficult medical and ethical questions for the patient and physician. Such pregnancies are at high risk for preterm birth, chorioamnionitis, and neonatal complications. Treatment can range from expectant management to pregnancy termination. This case presentation describes a patient with premature rupture of membranes at 21 weeks' gestation who gave birth at 35 weeks.

Management of 168 neonates weighing more than 2000 g receiving intrapartum chemoprophylaxis for chorioamnionitis. Evaluation of an early discharge strategy

OBJECTIVE

To determine whether sequential laboratory and clinical evaluations during the first 3 days of postnatal life can be used to safely limit the duration of antibiotic therapy for term neonates whose mothers received intrapartum antibiotic treatment for intra-amniotic infection (ie, chorioamnionitis).

METHODS

Since postpartum neonatal body fluid cultures can be falsely negative because of transplacental passage of maternal antibiotics, we prospectively followed up 6620 pregnancies for 28 months (December 1991 through March 1994) for the occurrence and treatment of chorioamnionitis. Neonatal antibiotic therapy was initiated and limited to 3 days or continued for 7 days or more in neonates with abnormal laboratory values or clinical signs that were consistent with sepsis on day 3 of postnatal age. Both groups were observed in the hospital for 24 to 48 hours after antibiotics were discontinued.

RESULTS

Of the 6620 pregnancies, 158 infants (2.4%) born to 155 mothers received intrapartum antibiotics for chorioamnionitis; 10 additional neonates diagnosed as having chorioamnionitis were transported from other hospitals (N = 168). Because of the absence of signs and negative cultures, 82% (137/168) were treated with antibiotics for 3 days, while 18% (31/168) received 7 days or more of therapy. In 84% of the 3-day group, discharge was accomplished by postnatal day 4 or 5, whereas all of the 7-day or more group were discharged after day 8. Follow-up calls placed 1 month after discharge disclosed no adverse outcomes or hospital readmissions in any of the infants in this survey.

CONCLUSIONS

Neonates with infection who are born to mothers pretreated with antibiotics for intra-amniotic infection can be reliably identified less than 72 hours after birth and treated appropriately. As 82% of at-risk patients are asymptomatic and have a negative body fluid culture, our data support the position that a full course of antibiotic therapy can be restricted to only those patients with clinical or laboratory signs of sepsis (18%). This will effective reduce the average length of hospital stay for intrapartum-treated neonates by a minimum of 3 to 4 days compared with a commonly used empiric therapy approach of continuing medication for 7 days or more. Perhaps hospital discharge can be further shortened if a 1- to 2-day posttreatment observation period is eliminated for all patients except those with a positive body fluid culture.