Antibiotic therapy for preterm premature rupture of the membranes

Outcomes after extended azithromycin administration in preterm premature rupture of membranes

BACKGROUND

Preterm premature rupture of membranes accounts for approximately one-quarter of all preterm deliveries and occurs in 2% to 3% of all pregnancies. With subclinical infection being a suspected cause of preterm premature rupture of membranes, the administration of prophylactic antibiotics is an accepted standard of care to extend the latency period. Historically, erythromycin was used in the antibiotic regimen recommended for women with preterm premature rupture of membranes during expectant management; however, azithromycin has recently been shown to be a suitable alternative.

OBJECTIVE

This study aimed to evaluate whether extended azithromycin administration affects the latency time in preterm premature rupture of membranes.

STUDY DESIGN

This was a retrospective multi-institutional cohort study in Washington, District of Columbia, of patients admitted from January 2012 to December 2019 with preterm premature rupture of membranes of singleton pregnancies between 23 0/7 and 33 6/7 weeks of gestation. Patients were excluded if they had multiple pregnancies, had an allergy to penicillin or macrolides, were in labor, had suspected placental abruptions, had overt chorioamnionitis, or had nonreassuring fetal status on presentation indicating the need for prompt delivery. Patients that received limited azithromycin administration (<2 days) and patients that received extended azithromycin administration (7 days) were compared. All patients otherwise received the institutional standard of 2 days of intravenous ampicillin followed by 5 days of oral amoxicillin. The primary outcome was length of gestational latency, defined as the time from membrane rupture to delivery. The selective secondary outcomes that were evaluated were rates of chorioamnionitis and adverse neonatal outcomes, including sepsis, respiratory distress, necrotizing enterocolitis, intraventricular hemorrhage, and neonatal death.

RESULTS

During the study period, 416 cases of preterm premature rupture of membranes were identified. Of the 287 patients who met the inclusion criteria, 165 (57.5%) received limited azithromycin administration, and 122 (42.5%) received extended azithromycin administration. Adjusted median gestational latency was significantly longer for patients who received extended azithromycin administration, extended by >3 days (2.6 days [interquartile range, 2.2-3.1] for limited azithromycin administration vs 5.8 days [interquartile range, 4.8-6.9] for extended azithromycin administration; P<.001). Neonatal secondary outcome evaluation was performed on 216 cases (76%). There was no difference in chorioamnionitis or adverse neonatal outcomes between the 2 groups.

CONCLUSION

Among patients with preterm premature rupture of membranes, extended azithromycin administration was associated with increased latency, without any effect on other maternal or neonatal outcomes.

The Short Cervix: A Critical Analysis of Diagnosis and Treatment

A short cervix in the second trimester is a significant risk factor for spontaneous preterm birth, preterm prelabor rupture of membranes, and subsequent adverse perinatal outcome. The pathophysiology is complex and multifactorial with inflammatory and/or infectious processes often involved. Biomarkers have been developed in an effort to predict preterm birth with varying degrees of success. The treatment options of cerclage, progesterone, pessary, and combination therapy are reviewed. Evidence-based protocols are summarized for singleton and multiple gestation.

A retrospective comparison of antibiotic regimens for preterm premature rupture of membranes

OBJECTIVE

To evaluate whether the use of ampicillin and azithromycin leads to a similar latency period in preterm premature rupture of membranes as ampicillin and erythromycin and whether the substitution of azithromycin for erythromycin effects rates of other outcomes.

METHODS

We performed a retrospective cohort study of women with preterm premature rupture of membranes between 24 and 34 completed weeks of gestation and compared two groups: those who received ampicillin and erythromycin and those who received ampicillin and azithromycin. Primary outcome was length of latency (defined as time from first antibiotic dose to delivery) and secondary outcomes were rates of chorioamnionitis, cesarean delivery, Apgar scores, birth weight, neonatal death, neonatal sepsis, and neonatal respiratory distress syndrome.

RESULTS

Of 168 women who met inclusion criteria, 75 received ampicillin and erythromycin and 93 received ampicillin and azithromycin. There was no difference in latency between groups: 9.6±13.2 days (erythromycin) compared with 9.4±10.0 (azithromycin) days (P=.40). Secondary outcomes did not differ between groups. We had 80% power to detect a difference of 5 days.

CONCLUSION

Among women with preterm premature rupture of membranes between 24 and 34 completed weeks of gestation, substitution of azithromycin for erythromycin in the recommended antibiotic regimen did not affect latency or any other measured maternal or fetal outcomes.

LEVEL OF EVIDENCE

III.

Relationship between antenatal group B streptococcal vaginal colonization and premature labour

OBJECTIVE

To determine whether a population of pregnant women with group B streptococcal (GBS) vaginal colonization had an increased risk of specific epidemiological and intrapartum risk factors for early onset GBS disease.

SETTING

Tertiary university centre in Ottawa, Ontario.

DESIGN

Hospital-based retrospective cohort study.

METHODS

Pregnant women who gave birth during a four-month period in 1994 were included in the study. Potential GBS risk factors were obtained from a review of medical records. The prevalence of each risk factor in colonized and noncolonized women was examined using chi(2) or Fisher's exact test. Multiple logistic regression was performed.

RESULTS

A total of 986 women, including 94 (9.5%) women colonized with GBS, were studied. The proportion of women younger than 20 years of age in the colonized group was 2.1% (two of 94) versus 4.6% (41 of 891) in the noncolonized group (P=0.28). Similar rates of multiple births were observed among the colonized and noncolonized groups (2.1% [two of 94] versus 2.5% [22 of 891], respectively) (P=0.94). Likewise, there were no significant differences in either group in the prevalence of a previous pregnancy affected by GBS or diabetes mellitus (P=0.82 and P=0.79, respectively). Multivariable analyses indicated that women who were colonized with GBS were more than twice as likely to deliver prematurely (below 37 weeks' gestational age) (odds ratio [OR] 2.43, 95% CI 1.39 to 4.23). Similarly, colonized women were more likely to be febrile during labour (at least 38 degrees C) (OR 5.05, 95% CI 1.70 to 15.02).

CONCLUSION

GBS vaginal colonization was associated with premature labour and intrapartum pyrexia in the population studied. According to Canadian and American guidelines, women with GBS vaginal colonization qualify for intrapartum chemoprophylaxis. The study results suggest that the identification of women at risk of premature labour may be one advantage of early prenatal screening for GBS.

A genetic association study of maternal and fetal candidate genes that predispose to preterm prelabor rupture of membranes (PROM)

OBJECTIVE

We sought to determine whether maternal/fetal single-nucleotide polymorphisms (SNPs) in candidate genes are associated with preterm prelabor rupture of membranes (pPROM).

STUDY DESIGN

A case-control study was conducted in patients with pPROM (225 mothers and 155 fetuses) and 599 mothers and 628 fetuses with a normal pregnancy; 190 candidate genes and 775 SNPs were studied. Single locus/haplotype association analyses were performed; false discovery rate was used to correct for multiple testing (q* = 0.15).

RESULTS

First, a SNP in tissue inhibitor of metalloproteinase 2 in mothers was significantly associated with pPROM (odds ratio, 2.12; 95% confidence interval, 1.47-3.07; P = .000068), and this association remained significant after correction for multiple comparisons. Second, haplotypes for Alpha 3 type IV collagen isoform precursor in the mother were associated with pPROM (global P = .003). Third, multilocus analysis identified a 3-locus model, which included maternal SNPs in collagen type I alpha 2, defensin alpha 5 gene, and endothelin 1.

CONCLUSION

DNA variants in a maternal gene involved in extracellular matrix metabolism doubled the risk of pPROM.

Does the combined antenatal use of corticosteroids and antibiotics increase late-onset neonatal sepsis in the very low birth weight infant?

OBJECTIVE

The purpose of this study was to determine whether the combined use of maternal antenatal corticosteroids and antibiotic therapy is associated with an increased risk of late-onset neonatal sepsis among very low birth weight infants.

STUDY DESIGN

The outcomes of infants admitted to the 3 Cincinnati neonatal intensive care units between May 1991 and May 2000 were retrospectively evaluated. Late-onset neonatal sepsis was defined either as the occurrence of a positive blood culture obtained after 72 hours of life with clinical signs of sepsis or as the need for >5 consecutive days of antibiotic therapy for presumed sepsis that initiated after 72 hours of life. Wilcoxon rank sum, chi-square test, and multiple logistic regression were used for analysis.

RESULTS

Among the parturients delivering the study infants, 434 women (24%) received corticosteroids only, 175 women (9%) received antibiotics only, 819 women (46%) received both corticosteroids and antibiotics, and 370 women (20%) received neither corticosteroids nor antibiotics. Among 1978 study infants, there were 732 infants (41%) with late-onset neonatal sepsis. By univariate analysis, the odds ratio for late-onset neonatal sepsis caused by combined corticosteroid and antibiotic use was 0.96 (95% CI, 0.89%, 1.04%). Multiple logistic regression analysis was used to evaluate the risk of combined corticosteroids and antibiotic use after controlling for potential covariates and confounders. After controlling for outborn birth (odds ratio, 1.3; 95% CI, 1.0%-1.8%), increasing gestational age at delivery (odds ratio, 0.63; 95% CI, 0.60%-0.66%), interaction between white race and male gender (P =.01) and interaction between antibiotics and prolonged rupture of membranes (P =.02), the use of corticosteroids and antibiotics was not associated with an increased risk of late-onset neonatal sepsis (P =.9).

CONCLUSION

The combined use of maternal corticosteroids and antibiotic therapy is not associated with an increased risk for late-onset neonatal sepsis.

In vitro sealing of punctured fetal membranes: potential treatment for midtrimester premature rupture of membranes

OBJECTIVE

Midtrimester premature rupture of membranes causes significant perinatal morbidity and death. No effective treatment exists. We investigated (1) whether a needle puncture in the fetal membranes could be sealed in vitro and (2) the optimal composition of the sealant to be used.

STUDY DESIGN

Membranes from second trimester pregnancies (16-24 weeks of gestation) were stretched over a modified syringe with a 2.5-cm open diameter. The syringe was filled with 20 mL of second trimester amniotic fluid, and the membrane was punctured with a 20-gauge needle. Sealants were injected into the amniotic fluid. The primary outcome variable was time for leakage of amniotic fluid. Median times for leakage for the formulations were compared by Wilcoxon exact rank sum test.

RESULTS

Platelets alone failed to seal the puncture site. All other formulations stopped leakage temporarily. Tisseel (Baxter Corp, Glendale, Calif) and cryoprecipitate/thrombin preparations led to more prolonged sealing of punctured amniotic membranes than platelets (P <.01) and were not significantly different from each other.

CONCLUSION

Of the sealants tested in vitro, amniotic membranes are best sealed by a fibrin/thrombin-based sealant.

No increase in rates of early-onset neonatal sepsis by non-group B Streptococcus or ampicillin-resistant organisms

OBJECTIVE

We assessed the impact of a risk-based approach to group B Streptococcus (GBS) prophylaxis on the rates of early-onset neonatal sepsis (EONS).

STUDY DESIGN

A retrospective cohort study of neonates born at a tertiary-care hospital from 1990 to 1996 was performed. Cases of EONS were identified among neonates born in a period without GBS prophylaxis (1990-1992) and compared with those born in a period with GBS prophylaxis (1993-1996). The antibiotic susceptibility data on each organism isolated in the blood culture were obtained.

RESULTS

In the period without prophylaxis, 99 cases of EONS were identified among 25,934 neonates for a rate of 3.8 per 1000 births. In the period with prophylaxis, 90 cases of EONS occurred among 34,262 neonates for a rate of 2.6 per 1000. The rate of GBS-EONS significantly decreased between the 2 periods (from 1.9 to 1.1, P =.01). There was a trend toward a decrease in the rate of EONS caused by non-GBS gram-positive organisms (from 1.2 to 0.7, P =.06). There was no significant increase in the rate of EONS caused by gram-negative or ampicillin-resistant organisms.

CONCLUSIONS

A risk-based approach to GBS prophylaxis reduced the incidence of GBS-EONS at a tertiary-care hospital. This decrease was not accompanied by an increase in the incidence of EONS by non-GBS or ampicillin-resistant organisms.

Activation of human progelatinase A/promatrix metalloproteinase 2 by Escherichia coli-derived serine proteinase

Treatment of human uterine cervical fibroblasts with commercial lipopolysaccharide (LPS) preparations from different serotypes of Escherichia coli effectively augmented the processing of mammalian progelatinase A/promatrix metalloproteinase (proMMP)-2 to a 62-kDa form of MMP-2. When purified proMMP-2 was incubated with LPS preparations, the proenzyme was similarly processed into the 62-kDa active MMP-2 in a time- and dose-dependent manner. By contrast, progelatinase B/proMMP-9 and prostromelysin 1/proMMP-3 were not activated. A serine proteinase inhibitor, phenylmethylsulfonyl fluoride, completely interfered with this LPS-mediated activation of proMMP-2. This is novel evidence that E. coli serine proteinase is a specific activator of proMMP-2. Thus, it is very likely that E. coli infection plays a crucial role in the degradation of connective tissues via the activation of proMMP-2, and the resultant active MMP-2 participates in the dysfunction of connective tissues such as in the preterm rupture of fetal membranes.

Neonatal sepsis and death caused by resistant Escherichia coli: possible consequences of extended maternal ampicillin administration

OBJECTIVE

Our goal was to evaluate the relationship between neonatal death caused by sepsis associated with ampicillin-resistant organisms and length of antibiotic exposure.

STUDY DESIGN

All neonatal deaths from culture-positive sepsis over a 3-year period were examined. Infants who were delivered at either the University of Mississippi Medical Center or at Saint Barnabas Medical Center at >/=24 weeks' gestation and died within 7 days of life were included. Information on the organism causing sepsis and its sensitivities was collected, and the number of doses of ampicillin administered to the mother before delivery was determined.

RESULTS

Of the 78 neonatal deaths, 35 met the inclusion criteria. There were 8 cases of sepsis from ampicillin-resistant Escherichia coli and 27 cases caused by other organisms. There was a statistically significant difference between the mean number of doses of ampicillin received by the ampicillin-resistant Escherichia coli group (17.6 +/- 5.5) compared with the other organisms group (4.9 +/- 3.6) (P <.001).

CONCLUSION

A relationship exists between neonatal death caused by ampicillin-resistant Escherichia coli and prolonged antepartum exposure to ampicillin.

Antenatal corticosteroids in preterm premature rupture of membranes

It is clear that there is no unequivocal indication for the use of antenatal corticosteroids in the preterm gestation with PROM. Extrapolating the effects seen in gestations with intact membranes, however, there are potential benefits in reduction of neonatal respiratory disease and intracranial hemorrhage at the expense of increased risks of maternal postpartum infection. Because the lifetime harm from the neonatal grave and the sequelae of infection in the mother are usually mild, we recommend that antenatal corticosteroids be administered to patients with PPROM between the gestational ages of 24-33 weeks in the absence of frank maternal or fetal infection or fetal compromise. With the increasing acceptance of antenatal corticosteroid therapy, it is unlikely that any further prospective randomized trials will be possible because withholding corticosteroids may expose patients to unacceptable potential harm. Therefore, clinical judgments may have to made based solely on the limited data presently available. Hopefully, future clinical investigations will provide useful information about the relation between antenatal corticosteroids and perinatal infections of the mother and infant in the setting of prophylactic antibiotic exposure. Additionally, there is also a need for information establishing a clinical profile for the patient with PPROM that accurately predicts when she is likely to enter spontaneous labor, thus allowing clinicians to increase the likelihood of appropriately administering corticosteroids within 1 week of delivery to maximize potential neonatal benefit.

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

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