Intraamniotic infection and the onset of labor in preterm premature rupture of the membranes

The purpose of this study was to examine the relationship between intraamniotic infection and the onset of labor in patients with preterm premature rupture of the membranes. Two hundred and thirty consecutive patients were admitted with premature rupture of the membranes to Yale-New Haven Hospital from January 1985 to July 1987. Amniotic fluid was retrieved by amniocentesis from 96% (221/230). Sixty-one patients were in labor on admission (27.6%, 61/221) and 39% of them (24/61) had a positive amniotic fluid culture. Patients in labor on admission were more likely to have a positive amniotic fluid culture than those who were not in labor on admission (24/61 versus 41/160, p = 0.049). Of the 160-patients who were not in labor on admission, 81 subsequently went into spontaneous labor; microbiologic information at the time of labor was known in 48 of these patients (59.2%). Seventy-five percent (36/48) of these patients had a positive amniotic fluid culture. The incidence of intraamniotic infection in quiescent women who subsequently went into labor was higher than that of patients admitted in active labor (75% versus 39%, p = 0.0004). These results provide a basis for the clinical impression that the onset of labor in women with preterm premature rupture of the membranes is associated with a subclinical intraamniotic infection. The mechanisms responsible for the onset of labor in women without an intraamniotic infection may be associated with an extraamniotic infection (e.g., deciduitis) or a noninfectious process.     

Prevention of preterm labor and premature rupture of the membranes

Preterm delivery is currently the leading cause of perinatal morbidity and mortality. PROM is the most common easily identifiable cause of preterm delivery, present in 20-30% of preterm births. The conflicting results of success in prematurity prevention programs obtained by different investigators probably reflect the populations that were studied. Meis and colleagues divided the etiologies of low birth weight into four categories: 1) Low birth weight in infants greater than 37 weeks' gestation, 2) PROM, 3) birth weight caused by medical complications, and 4) idiopathic premature labor (IPL). In patients seen in the county health department clinic (1,529 births), IPL accounted for 25% of birth weights less than 2,500 g. In contrast, patients seen in a large private obstetric practice (1,327 births), IPL was the etiology of low birth weight in 47% of patients. Not surprisingly, a prematurity prevention program has not reduced the rate of low birth weight for the public patients but has resulted in decreases of low birth weight for the private patients. Paramount in the prevention of preterm birth is physician education regarding known risk factors, signs and symptoms of preterm labor, and the role of close follow-up in the patients identified as high risk. Papiernik's success with limitation of physical efforts and work leave, when appropriate, in high-risk patients is laudable and, many feel, should be emulated. Prenatal care must include for each woman education concerning the signs and symptoms of preterm labor and PROM. Individual risk factors must be ascertained and followed with appropriate observation, therapy, and/or modification plans. Finally, the early detection of preterm labor will expedite prompt treatment and so increase chances of postponing delivery.     

Symptoms that precede preterm labor and preterm premature rupture of the membranes

Great emphasis has been placed on recognition of the early warning symptoms of preterm labor by both pregnant women and health care providers. In addition to the expected increase in both painless and painful uterine contractions, several symptoms have been commonly cited in textbooks and patient educational materials as preceding preterm labor including menstrual-like cramps, backache, pelvic pressure, and an increased amount of vaginal discharge. We interviewed 107 women with preterm labor, 102 women with preterm prematurely ruptured membranes, and 106 ambulatory normal pregnant women to ascertain the frequency of each of eight putative warning symptoms of preterm labor in each group. Preterm labor patients were distinguished as expected from both normal women and amniorrhexis patients by a greater frequency of painful and painless contractions. Menstrual cramps, backache, and increased vaginal discharge, symptoms often said to be normally present in pregnancy, were also significantly more common in preterm labor patients than in women with preterm membrane rupture and in normal subjects.     

Perinatal outcomes in pregnancies with oligohydramnios after preterm premature rupture of membranes

Objective: Our purpose was to determine whether singleton pregnancies complicated by preterm premature rupture of membranes (PPROM) and oligohydramnios are at an increased risk of having maternal and neonatal morbidity.

Methods: We performed a retrospective analysis of 389 women with PPROM between 24 and 34 weeks of gestation in a single tertiary center during 2008–2014. Patients were divided into two groups on the basis of amniotic fluid index (AFI)?n?=?188) or AFI?≥?5?cm (n?=?201). Perinatal outcomes were compared according to amniotic fluid volume. The Student's t-test and Mann–Whitney U test were used to compare variables with normal and abnormal distribution, respectively. Categorical variables were examined by the chi-square test.

Results: Patients with an AFI?p?p?=?0.029) and emergency cesarean delivery (p?=?0.043) and a lower neonatal Apgar score at first minute (p?=?0.004).

Conclusion: Initial oligohydramnios after PPROM is associated with shorter latency to delivery, higher rate of clinical chorioamnionitis, higher rate of emergency cesarean delivery, and lower 1-min Apgar score.     

The relationship between practice setting and management of preterm premature rupture of membranes

Objective.?To compare preterm premature rupture of membranes (PPROM) management between maternal-fetal medicine (MFM) providers practicing in an academic university (AU) versus other settings (NAU).

Methods.?Secondary analysis of a national survey of 1375 MFM providers of whom 504 (37%) responded and answered queries on demographic and practice characteristics and various PPROM management issues.

Results.?Fifty-three percent of the respondents were in an AU practice setting. Providers in AU and NAU settings reported a similar prevalence of corticosteroid (99% vs. 100%), antibiotic (99% vs. 100%), and tocolytic (74% vs. 76%) use. There was significant variability between NAU and AU providers in issues related to the evaluation and expectant management of PPROM. NAU providers, as compared to AU providers, more commonly reported performing diagnostic amniocentesis in the acute evaluation of PPROM (72% vs. 61%, p?=?0.02). There was a higher prevalence of fetal lung maturity assessment among NAU providers (84%) as compared to AU providers (73%, p?=?0.005) and significant variability was noted with respect to the fetal lung maturity tests used (p?<?0.0001). NAU providers continued expectant management later into gestation than AU providers (p?=?0.002). Significant variability was also noted in the use of antepartum surveillance techniques (p?=?0.01).

Conclusion.?MFM practitioners from academic universities and non-academic settings utilize similar management strategies for PPROM in regard to corticosteroid, tocolytic, and antibiotic use. However, differences are evident in issues related to the evaluation and expectant management of patients with PPROM.     

Activation of coagulation system in preterm labor and preterm premature rupture of membranes

Objective: Thrombin, originally discovered as a coagulation factor, is a multifunctional protease capable of inducing myometrial contractions in vitro and in vivo. This enzyme has been implicated in the mechanisms of premature labor. Plasma concentrations of thrombin-antithrombin (TAT) complexes are an index of in vivo thrombin generation. The purpose of this study was to determine whether patients with premature labor and preterm premature rupture of membranes (PROM) have evidence of increased thrombin generation in maternal blood, as determined by the TAT complex concentrations. Methods: A cross-sectional study was designed to determine plasma concentrations of TAT complexes in 110 women in the following groups: non-pregnant women (n = 20); normal pregnant women (n = 30); women in preterm labor with intact membranes (n = 30); and women with preterm PROM (n = 30). TAT complex concentrations were determined with a sensitive and specific immunoassay. Statistical analysis was conducted with non-parametric statistics. Results: Patients with preterm labor and intact membranes had a significantly higher median plasma TAT complex concentration than normal pregnant women (women in preterm labor, median 19.1 μg/l; range 7.4-406 vs. normal pregnant women, median 15 μg/l; range 6.8-32.5; p = 0.03). Patients with preterm PROM had a higher median TAT complex concentration than normal pregnant women (preterm PROM, median 19.1 μg/l; range 4.7-738.6 vs. normal pregnant women, median 15 μg/l; range 6.8-32.5; p = 0.03). Normal pregnancy was associated with a higher median plasma TAT complex concentration than the non-pregnant state (normal pregnant women, median 15 μg/l; range 6.8-32.5 vs. non-pregnant women, median 2.7 μg/l; range 0.9-14.2; p < 0.001). Conclusion: Preterm labor and preterm PROM are associated with an excess generation of thrombin.     

The relationship between practice setting and management of preterm premature rupture of membranes.

OBJECTIVE: To compare preterm premature rupture of membranes (PPROM) management between maternal-fetal medicine (MFM) providers practicing in an academic university (AU) versus other settings (NAU). METHODS: Secondary analysis of a national survey of 1375 MFM providers of whom 504 (37%) responded and answered queries on demographic and practice characteristics and various PPROM management issues. RESULTS: Fifty-three percent of the respondents were in an AU practice setting. Providers in AU and NAU settings reported a similar prevalence of corticosteroid (99% vs. 100%), antibiotic (99% vs. 100%), and tocolytic (74% vs. 76%) use. There was significant variability between NAU and AU providers in issues related to the evaluation and expectant management of PPROM. NAU providers, as compared to AU providers, more commonly reported performing diagnostic amniocentesis in the acute evaluation of PPROM (72% vs. 61%, p = 0.02). There was a higher prevalence of fetal lung maturity assessment among NAU providers (84%) as compared to AU providers (73%, p = 0.005) and significant variability was noted with respect to the fetal lung maturity tests used (p < 0.0001). NAU providers continued expectant management later into gestation than AU providers (p = 0.002). Significant variability was also noted in the use of antepartum surveillance techniques (p = 0.01). CONCLUSION: MFM practitioners from academic universities and non-academic settings utilize similar management strategies for PPROM in regard to corticosteroid, tocolytic, and antibiotic use. However, differences are evident in issues related to the evaluation and expectant management of patients with PPROM.     

Preterm labor, preterm premature rupture of membranes, and chorioamnionitis

In this article, the author reviews the etiology and biochemical links between infection and preterm birth, the problem of preterm birth, and the management of infection-related risks of preterm birth. The management section reviews current opinions regarding prophylactic antibiotic therapy in the prevention of preterm birth, adjunctive antibiotic therapy in the treatment of preterm labor with and without rupture of membranes, and antibiotic therapy of intra-amniotic infection (clinical chorioamnionitis, IAI). Finally, the article reviews the risk of neurodevelopmental handicap potentially associated with IAI.     

Lewis phenotype in women with preterm labor and premature rupture of the membranes

Objective: The purpose of this study was to evaluate the possible association between Lewis phenotype status in pregnant women and preterm labor (PTL) or preterm rupture of the membranes (PROM).Methods: Red blood cell (RBC) Lewis phenotype was determined in 113 pregnant women admitted for PTL or PROM and in 121 controls. The results were controlled for the influence of race on Lewis phenotype.Results: Pregnancy was associated with a higher frequency in women with the a-b- phenotype. There was no association between RBC Lewis phenotype and the occurrence of PTL or PROM.Conclusions: A susceptibility to PTL or PROM is not due to a lack of Lewis antigen expression on the plasma membrane of the vaginal mucosa.     

Use of the fetal biophysical profile in severe oligohydramnios after preterm premature rupture of the membranes

A protocol of expectant management using daily fetal biophysical assessment was applied to 23 consecutive women with severe oligohydramnios after preterm premature rupture of the membranes. A persistently low biophysical score (less than or equal to 6 on two examinations two hours apart) in the presence of a nonreactive nonstress test and absence of fetal breathing was used as an indication for delivery. The pregnancy outcome in this group was compared to that in a historic control group managed similarly except that an abnormal biophysical assessment was not an indication for delivery. The results suggest that the management of women with severe oligohydramnios after preterm premature rupture of the membranes with daily fetal biophysical profiles decreases the incidence of low five-minute Apgar scores as well as that of maternal and neonatal infection.     

Comparison of changes in etiologic microorganisms causing early-onset neonatal sepsis between preterm labor and preterm premature rupture of membranes

Objective: To investigate changes in the etiologic microorganisms causing early-onset neonatal sepsis (EONS) in preterm labor (PTL) or preterm premature rupture of membranes (pPROM) cases over the past 16 years and to analyze the associated factors.

Methods: We included consecutive singleton pregnancies delivered before 34 weeks due to PTL or pPROM. The etiologic microorganisms causing EONS in PTL and pPROM cases were compared between period 1 (1996–2004) and period 2 (2005–2012).

Results: There was no difference in the incidence of Gram-positive bacteria causing EONS between period 1 and 2, either in PTL (2.0% versus 2.1%, p?=?1.0) or in pPROM (1.5% versus 1.6%, p?=?1.0). However, the incidence of EONS caused by Gram-negative bacteria was significantly increased in pPROM (0.6% versus 2.7%, p?=?0.040) during period 2, compared to period 1; but not in PTL (0.3% versus 1.2%, p?=?0.211). Multivariable analysis revealed that a prolonged ROM-to-delivery interval (>7?d) was significantly associated with EONS caused by Gram-negative bacteria in pPROM (odds ratio: 6.6, 95% confidence interval: 1.4–31.8, p?=?0.018).

Conclusions: The etiologic microorganisms causing EONS have changed over the past 16 years in pPROM cases but not in PTL cases.     

Fetal membrane inflammatory cytokines: a switching mechanism between the preterm premature rupture of the membranes and preterm labor pathways

Inflammatory cytokines are involved in both preterm labor and preterm premature of the membranes pathways; however, the interaction between TNF-alpha and its receptors may dictate the clinical outcome of pregnancy.     

Preterm premature rupture of the fetal membranes complicated by oligohydramnios

Preterm premature rupture of the fetal membranes complicated by oligohydramnios may have significant impact and sequelae on pregnancy outcome. In this article the role of amniotic fluid in fetal development, especially lung development, is reviewed; complications resulting from oligohydramnios are outlined; and the evaluated therapeutics and management schemes are delineated.     

Analysis of pregnancy and labor course in patients after preterm premature rupture of membranes

OBJECTIVE OF THE STUDY: The aim of this study was to compare the pregnancy and labor course in patients hospitalized due to PROM in relation to patients with membrane rupture at term of labor. MATERIALS AND METHODS: The study group consisted of 70 gravidas hospitalized in the Department of Pathological Pregnancy. The control group consisted of 70 patients. Special attention was paid to: time of PROM, pregnancy outcome and mode of delivery, obstetrical history, the symptoms of intrauterine infection. CONCLUSIONS: 1. The ascending infection after PROM was the most common indication for pregnancy termination. 2. There is a significant difference in pathological obstetrical history between patients hospitalized due to PROM and control group. 3. There is no significant difference in mode of delivery between study and control group.     

The relationship between prior cervical conization, cervical microbial colonization and preterm premature rupture of the membranes.

The occurrence of prior cervical conization and the cervical microbial colonization was investigated in 38 women with idiopathic preterm labor, 35 women with preterm premature rupture of the membranes (PPROM) and 75 normal pregnant women at 26-34 weeks of gestation. Data were analyzed by Fisher's exact test (two-tailed). The frequency of prior cervical conization was significantly higher in PPROM patients compared to normal pregnant women (P < 0.001) and to patients in preterm labor (P < 0.01). Lactobacilli occurred with a lower frequency in patients with PPROM compared to patients in preterm labor (P < 0.05) and control patients (P = 0.0543)-and with a lower frequency in patients with prior cervical conization (P < 0.05). All other microorganisms occurred with the same frequencies in all groups. The absence of lactobacilli may indicate changes in the cervical flora, which could increase the risk of PPROM. Prior cervical conization may impair the antimicrobial defense-mechanisms in the cervix, which could facilitate ascending microbial colonization. This may lead to a release of prostaglandins and proteolytic enzymes and subsequently preterm labor and rupture of the membranes.