Prevention of premature birth by screening and treatment for common genital tract infections: results of a prospective controlled evaluation

Accuracy of salivary estriol testing compared to traditional risk factor assessment in predicting preterm birth

OBJECTIVE

The objective was to compare the predictive accuracy (percentage of correct vs incorrect predictions) of salivary estriol levels (SalEst; Biex, Inc, Dublin, Calif) with that of the modified Creasy score for predicting preterm labor followed by preterm delivery.

STUDY DESIGN

A triple-blinded prospective trial was conducted at 8 US centers.

RESULTS

Among 601 evaluable patients, serial salivary estriol testing correctly predicted the appropriate outcome 91% of the time and the Creasy scoring method correctly predicted the appropriate outcome 75% of the time (McNemar test P <. 001). Among subjects with Creasy scores >/=10 (high-risk group, n = 152), use of salivary estriol testing correctly predicted the end point 87% of the time, compared with only 7.2% correctly predicted by modified Creasy scoring (McNemar test P <.001).

CONCLUSION

Salivary estriol assessment was more accurate in predicting outcome than was modified Creasy scoring.

The etiology of premature rupture of the membranes

The etiology of PROM is multifactorial. It is clear that maternal enzymes, maturational and mechanical forces, chorionicamniotic membrane phospholipid content, collagen disruption, amniotic cell cytokines induced by fetal signals, and bacterial phospholipases and collagenases all play major and interrelated roles. It is also clear that the production of oxytocic prostaglandins is a major, if not exclusive, common pathway leading to PROM and preterm delivery. The increasing awareness of the fetal role, i.e., fetal interleukins, fetal polymorphonuclear leukocytes and type V collagenase, make this area of research ripe for further investigation. The complex host defense mechanisms and biologic variability make any universal treatment impossible. Even with a specific etiology determined, the reduced availability of pharmacologic interventions for the fetal compartment portend suboptimal success. Therefore, it appears that continued research and aggressive measures to optimize the quality and availability of prenatal care are the best foci of our efforts.

A commensal symbiosis between Prevotella bivia and Peptostreptococcus anaerobius involves amino acids: potential significance to the pathogenesis of bacterial vaginosis

In both batch and continuous culture, Peptostreptococcus anaerobius was able to grow in vaginal defined medium with Prevotella bivia, but not in pure culture. Growth of P. anaerobius was increased by 238% (P < 0.001) in peptone-supplemented vaginal defined medium conditioned by prior growth of P. bivia. Analysis of P. bivia culture supernatants showed a net accumulation of amino acids and subsequent growth of P. anaerobius in the conditioned supernatants resulted generally in amino acid utilization. Supplementation of peptone-supplemented vaginal defined medium with amino acids in concentrations similar to those available after prior growth with P. bivia were growth-stimulatory (246%, P=0.006) for P. anaerobius. Increased availability of amino acids by P. bivia is proposed as a mechanism to support the observed in vitro commensal symbiosis between P. bivia and P. anaerobius.

Risk factors associated with preterm (<37+0 weeks) and early preterm birth (<32+0 weeks): univariate and multivariate analysis of 106 345 singleton births from the 1994 statewide perinatal survey of Bavaria

OBJECTIVE

The study was conducted to identify medical, obstetrical and social risk factors associated with early preterm births (<32+0 gestational weeks).

STUDY DESIGN

The Statewide Perinatal Survey of Bavaria is a collection of perinatal data from all Bavarian maternity units using a uniform numbered questionnaire. Data on 106345 singleton births from the 1994 Survey were analysed using univariate and multivariate logistic regression analysis.

RESULTS

In the multivariate analysis, early preterm birth was associated with premature rupture of the membranes (odds ratio (OR) 1.6, 95% confidence interval (CI) 1.37-1.86), treatment for infertility (OR 1.7, 95% CI 1.19-2.34), previous induced abortion (OR 1.8, 95% CI 1.57-2.13), maternal age >35 years (OR 1.8, 95% CI 1.47-2.16), premature cervical dilatation (OR 2.3, 95% CI 1.86-2.94), a history of stillbirth (OR 3.2, 95% CI 2.13-4.83), a history of preterm birth (OR 3.3, 95% CI 2.45-4.48), maternal age <18 years (OR 3.4, 95% CI 2.03-5.61), malpresentation (OR 3.9, 95% CI 3.10-4.93), preeclampsia (OR 4.0, 95% CI 3.20-4.94), uterine bleeding (OR 5.0, 95% CI 4.08-6.02), preterm labour (OR 7.0, 95% CI 5.94-8.22), and chorioamnionitis (OR 22.3, 95% CI 17.40-28.66).

CONCLUSION

These data identify a subgroup of women at an increased risk for early preterm birth and may benefit from an intensified prenatal care. Risk factors related to the obstetrical history, genital infections, preeclampsia and maternal age are the most relevant for early preterm birth.

Bacterial vaginosis and disturbances of vaginal flora: association with increased acquisition of HIV

BACKGROUND

Cross-sectional studies suggest an association between bacterial vaginosis (BV) and HIV-1 infection. However, an assessment of a temporal effect was not possible.

OBJECTIVES

To determine the association of BV and other disturbances of vaginal flora with HIV seroconversion among pregnant and postnatal women in Malawi, Africa.

DESIGN

Longitudinal follow-up of pregnant and postpartum women.

METHODS

Women attending their first antenatal care visit were screened for HIV after counselling and obtaining informed consent. HIV-seronegative women were enrolled and followed during pregnancy and after delivery. These women were again tested for HIV at delivery and at 6-monthly visits postnatally. Clinical examinations and collection of laboratory specimens (for BV and sexually transmitted diseases) were conducted at screening and at the postnatal 6-monthly visits. The diagnosis of BV was based on clinical criteria. Associations of BV and other risk factors with HIV seroconversion, were examined using contingency tables and multiple logistic regression analyses on antenatal data, and Kaplan-Meier proportional hazards analyses on postnatal data.

RESULTS

Among 1196 HIV-seronegative women who were followed antenatally for a median of 3.4 months, 27 women seroconverted by time of delivery. Postnatally, 97 seroconversions occurred among 1169 seronegative women who were followed for a median of 2.5 years. Bacterial vaginosis was significantly associated with antenatal HIV seroconversion (adjusted odds ratio = 3.7) and postnatal HIV seroconversion (adjusted rate ratio = 2.3). There was a significant trend of increased risk of HIV seroconversion with increasing severity of vaginal disturbance among both antenatal and postnatal women. The approximate attributable risk of BV alone was 23% for antenatal HIV seroconversions and 14% for postnatal seroconversions.

CONCLUSIONS

This prospective study suggests that progressively greater disturbances of vaginal flora, increase HIV acquisition during pregnancy and postnatally. The screening and treating of women with BV could restore normal flora and reduce their susceptibility to HIV.

Nutritional and antimicrobial interventions to prevent preterm birth: an overview of randomized controlled trials

The study was conducted to assess the effectiveness of interventions for the prevention or treatment of nutritional and infectious disorders during pregnancy on preterm birth rates. Cochrane systematic reviews or any other more up-to-date systematic review of antimicrobial and nutritional interventions were sought. Electronic searches of the Cochrane Controlled Trials Register were carried out to identify any trials published since the most recent update of the systematic review. Also, authors of Cochrane systematic reviews, which have not been updated recently, were contacted regarding new information. Systematic reviews of nutritional and antimicrobial interventions during pregnancy, reporting preterm delivery rates (delivery before 37 weeks) and "prematurity" (including low birth weight) either as primary or secondary outcomes, were included. General interventions without a specific nutritional supplementation or antimicrobial component were not considered for inclusion. Interventions to stop labor or prolong pregnancy after a diagnosis of preterm labor were excluded. For each systematic review, data on preterm delivery rate by intervention group was obtained. The total number of trials in the review, number of trials reporting preterm birth as an outcome, number of participants and events have been systematically extracted. Eighteen systematic reviews (10 nutritional and 8 antimicrobial) were considered. Our results indicated that, overall, the treatment of asymptomatic bacteriuria reduces the incidence of preterm birth or low birth weight (< 2500 gm) (typical relative risk (RR): 0.67; 95 percent confidence interval (CI): 0.52-0.85). The protective effect of treating asymptomatic bacteriuria for preterm delivery persisted when only the three trials reporting preterm delivery (< 37 weeks) were included in the meta-analysis (typical RR: 0.53, 95 percent CI: 0.33-0.86). Routine iron supplementation prevents maternal anemia and one trial comparing routine versus selective iron supplementation showed a statistically nonsignificant reduction in preterm birth. Zinc, magnesium, and fish oil supplementations show promising results in reducing preterm birth, but the evidence is not strong. Calcium supplementation remains controversial, although there was a statistically significant reduction in preterm delivery in the subgroup of women at high risk of developing hypertension during pregnancy. Two trials with use of metronidazole (alone or with erythromycin) showed a reduction in preterm delivery in women who were at a high risk of preterm delivery and had bacterial vaginosis at screening. We have concluded that asymptomatic bacteriuria should be screened and treated in all settings that offer antenatal care. Single dose treatment seems to be as effective as longer (4-7 days) treatment, although this needs to be confirmed by a large, methodologically rigorous trial. There are a number of promising interventions such as calcium supplementation in women with low calcium intake, iron, zinc, magnesium, and fish oil supplementation, and treatment of bacterial vaginosis in women at high risk of preterm delivery that need additional research to determine a possible role for prevention of preterm delivery.

Preterm birth: associations with genital and possibly oral microflora

Opportunistic pathogenic microbes are indigenous to the female lower genital tract and etiologic in many types of pelvic infections and, apparently, a portion of preterm birth (PTB) cases. Bacterial vaginosis (BV) is a clinical syndrome based on an altered genital microflora in which Gardnerella vaginalis; anaerobic species primarily among Prevotella, Porphyromonas, Bacteroides, Peptostreptococcus, and Mobiluncus; Mycoplasma hominis; and Ureaplasma urealyticum become predominant in vaginal secretions. This BV complex of microbes, compared to a normal vaginal microflora dominated by facultative lactobacilli, is associated with significantly increased risks for preterm labor, preterm premature rupture of membranes, PTB, and other perinatal infectious complications. Pathogenetic mechanisms include an ascending route of infection and/or inflammatory process due to microbial products and maternal and/or fetal response(s) with production of prostaglandins and cytokines. In the presence of periodontal disease, oral opportunistic pathogens and/or their inflammatory products also may have a role in prematurity via a hematogenous route. Fusobacterium nucleatum, a common oral species, is the most frequently isolated species from amniotic fluid cultures among women with preterm labor and intact membranes. Also, the species and subspecies of fusobacteria identified from amniotic fluid most closely match those reported from healthy and diseased subgingival sites, namely F. nucleatum subspecies vincentii and F. nucleatum subspecies nucleatum, compared to strains identified from the lower genital tract. Although these fusobacteria also could be acquired through cunnilingus from a partner, new data associating maternal periodontal disease with preterm low birth weight taken with the isolation of F. nucleatum, Capnocytophaga, and other oral species from amniotic fluid support further study of a possible additional route, oral-hematogenous, to PTB.

Potential pathogenic mechanisms of periodontitis associated pregnancy complications

During normal pregnancy, maternal hormones and locally acting cytokines play a key role in regulating the onset of labor, cervical ripening, uterine contraction, and delivery. Maternal infections during pregnancy have been demonstrated to perturb this normal cytokine and hormone-regulated gestation, sometimes resulting in preterm labor, preterm premature rupture of membranes, and preterm low birth weight (PLBW), i.e., < 2,500 g and < 37 weeks of gestation. Our research focus has been to determine whether periodontal infections can provide sufficient challenge to the mother to trigger PLBW. New experiments from 48 case-control subjects have measured gingival crevicular fluid (GCF) levels of PGE(2) and IL-1-beta to determine whether mediator levels were related to current pregnancy outcome. In addition, the levels of 4 periodontal pathogens were measured by using microbe-specific DNA probes. Results indicate that GCF-PGE(2) levels are significantly higher in PLBW mothers, as compared with normal birth weight (NBW) controls (131.4 +/- 21.8 vs. 62.6 +/- 10.3 [mean +/- SE ng/mL], respectively, at P = 0.02). Furthermore, within primiparous PLBW mothers, there was a significant inverse association between birth weight (as well as gestational age) and GCF-PGE(2) levels at P = 0.023. These data suggest a dose-response relationship for increasing GCF-PGE(2) as a marker of current periodontal disease activity and decreasing birth weight. Microbial data indicate that 4 organisms associated with mature plaque and progressing periodontitis--bacteroides forsythus, Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans, and Treponema denticola--were detected at higher levels in PLBW mothers, as compared to NBW controls. These data suggest that biochemical measures of maternal periodontal status and oral microbial burden are associated with current PLBW.

Diagnosis of Trichomonas vaginalis in adolescent females: InPouch TV culture versus wet-mount microscopy

PURPOSE

This study compared the InPouch TV culture to wet-mount, Diamond's culture medium, and Papanicolaou (Pap) smear for the diagnosis of trichomonas infection in sexually active adolescents.

METHODS

A total of 467 subjects were recruited among 12-18-year-old girls who received pelvic examinations at two urban adolescent clinics. All girls were tested by wet-mount and InPouch TV. In addition 339 of 467 had cultures in Diamond's medium and 366 of 467 had Pap smears. Specimens were collected for InPouch TV and Diamond's cultures and read at 24-48 h and 5 days, and in the case of Diamond's cultures, also at 7 days. In a subset of subjects (268 of 467) who had all four tests done, sensitivities and specificities were calculated using Diamond's culture as the "gold standard."

RESULTS

In the 467 subjects, 73 (15.6%) tested positive for trichomonas by at least one method. In the subset with all four tests done, sensitivities of the wet-mount and InPouch TV were 36% and 81%, respectively; while that of the Pap smear was 56%. The culture media were equally efficient in identifying Trichomonas vaginalis. There were no differences found between subjects with or without trichomonas infections in gynecological symptoms, previous history of sexually transmitted diseases, or use of a condom at last intercourse.

CONCLUSIONS

InPouch TV culture is a good diagnostic method for T. vaginalis because of its long shelf-life, relatively low expense, and high sensitivity (over twice as sensitive as wet-mount).

Managing sexually transmitted diseases in adolescents

Control of sexually transmitted diseases (STDs) in adolescents is a primary responsibility of health care providers. Using the tools of history and physical examination, and drawing on the awareness of different stages of adolescent development, health care providers can define at-risk for STDs. This article discusses screening practices, disease control through reporting and preventive counseling, and treatment guidelines for common STD syndromes.

Prediction of preterm labour in multiple pregnancies

Various methods of predicting preterm labour in both singleton and multiple pregnancies have been studied including risk scoring systems, home uterine activity monitoring, cervical assessment and biochemical methods. In practice, risk scoring systems for preterm delivery perform poorly. Consensus in the literature regarding the usefulness of home uterine activity monitoring is lacking and well designed randomized controlled trials are required. Transvaginal ultrasound assessment of the cervix appears to have a role to play in the prediction of preterm labour. The presence of IFN in cervicovaginal fluid in the late second and early third trimesters is an important risk factor for preterm labour in asymptomatic women with multiple pregnancies. Preterm labour may be mediated in part by inflammatory cytokines. The measurement of these inflammatory cytokines in cervical secretions may also prove helpful in the prediction of preterm labour. It is anticipated that an improved ability to predict preterm labour in both singleton and multiple pregnancies will depend on increasing understanding of the condition's pathophysiology.

The pediatrician and the sexually active adolescent. A primer for sexually transmitted diseases

Sexual activity is a common practice among young adolescents, placing them at high risk for STDs, many of which have long-term consequences. Early diagnosis and treatment are essential to limit both the consequences and the spread of these infections. The clinician has a responsibility to the adolescent patient to recognize and treat these diseases. Using history and physical examination, the clinician should be able to determine an adolescent's risk for an STD, and, based on this risk, undertake the appropriate evaluations. Patient treatment, follow-up, and management of sex partners are then guided by the results of either presumptive or definitive diagnostic tests.

Impact of metronidazole therapy on preterm birth in women with bacterial vaginosis flora (Gardnerella vaginalis): a randomised, placebo controlled trial

OBJECTIVE

To ascertain whether metronidazole treatment of women with a heavy growth of Gardnerella vaginalis during mid-pregnancy would reduce the risk of spontaneous preterm birth.

DESIGN

A multicentre, randomised, placebo-controlled trial.

SETTING

Four metropolitan hospitals.

PARTICIPANTS

Eight hundred and seventy-nine singleton women with a heavy growth of G. vaginalis or Gram stain indicative of bacterial vaginosis at 19 weeks of gestation.

INTERVENTIONS

Oral metronidazole (400 mg) or placebo twice daily for two days at 24 weeks of gestation, and at 29 weeks if G. vaginalis found in test-of-cure swab four weeks after treatment.

MAIN OUTCOME MEASURES

Spontaneous preterm birth less than 37 weeks.

RESULTS

Intention-to-treat analysis showed no difference between metronidazole and placebo groups in overall preterm birth (31/429 [7.2%] vs 32/428 [7.5%]) or spontaneous preterm birth (20/429 [4.7%] vs 24/428 [5.6%]). Among the 480 women with bacterial vaginosis treatment had no effect on spontaneous preterm birth (11/242 [4.5%] vs 15/238 [6.3%]). In the subset of 46 women with a previous preterm birth, women in the metronidazole group showed a significant reduction in spontaneous preterm birth (2/22 [9.1%] vs 10/24 [41.7%], OR 0.14, 95% CI 0.01-0.84). A treatment effect was also found in compliant women with a previous preterm birth and bacterial vaginosis (0/14 [0%] vs 6/17 [35.3%], OR 0.0, 95% CI 0.0-0.94).

CONCLUSION

Metronidazole treatment of women with a heavy growth of G. vaginalis or bacterial vaginosis did not reduce the preterm birth rate. Among women with a previous preterm birth, treatment reduced the risk of spontaneous preterm birth. Further studies are required to confirm these findings.

Fetal fibronectin, endotoxin, bacterial vaginosis and cervical length as predictors of preterm birth and neonatal morbidity in twin pregnancies

OBJECTIVE

To evaluate the predictive values of fetal fibronectin, bacterial vaginosis, endotoxin and cervical length for preterm birth (< 35 and < 37 weeks) and neonatal morbidity in twin pregnancies.

PARTICIPANTS

One-hundred and twenty-one women with twin pregnancies recruited into a prospective longitudinal study at three antenatal clinics in the southwest of Sweden.

METHODS

Cervical or vaginal fluid was sampled and determined for fetal fibronectin (> or = 0.05 microgram/mL was used as cutoff), endotoxin (> or = 100 pg/mL) and bacterial vaginosis (presence of clue cells) at two week intervals from 24 to 34 weeks of gestation. The cervical length was measured with transvaginal sonography at the same time intervals.

MAIN OUTCOME MEASURES

Occurrence of preterm birth (< 35 and < 37 weeks of gestation) and neonatal morbidity.

RESULTS

All positive fetal fibronectin samples obtained at screening between 24 and 34 weeks predicted birth < 35 weeks (RR 18.0; 95% CI 2.2-145.9). A positive fetal fibronectin at 28 weeks of gestation predicted delivery < 35 weeks (RR 6.3; 95% CI 2.6-15.1) with a sensitivity, specificity, positive and negative predictive value of 50.0, 92.0, 62.5 and 87.3%, respectively. An independent association between fetal fibronectin at 28 weeks and preterm birth (< 35 weeks) was verified with logistic regression (P = 0.03). A positive fetal fibronectin at 28 weeks of gestation predicted neonatal morbidity (RR 5.1; 95% CI 2.4-11.0) and a longer period of care at the neonatal intensive care unit. The predictive power of cervical sonography was generally low but cervical length (cutoff < or = 33 mm) measured at 28 weeks of gestation was significantly associated with birth < 37 weeks (RR 2.2; 95% CI 1.1-4.2). The presence of endotoxin correlated to bacterial vaginosis, but these tests were not significantly related to preterm birth or neonatal morbidity.

CONCLUSIONS

Fetal fibronectin predicted preterm birth and neonatal morbidity in twin pregnancies. The predictive value of cervical length determinations was low. Endotoxin and bacterial vaginosis had no predictive power for preterm delivery in this study.

In vitro activities of 10 antimicrobial agents against bacterial vaginosis-associated anaerobic isolates from pregnant Japanese and Thai women

The in vitro activities of 10 antimicrobial agents against 159 bacterial vaginosis-associated anaerobic isolates from pregnant Japanese and Thai women were determined. Clindamycin, imipenem, cefmetazole, amoxicillin, amoxicillin-clavulanate, and metronidazole were highly active against all anaerobic isolates except Prevotella bivia and Mobiluncus species, which were resistant to amoxicillin and metronidazole, respectively. Cefotiam, ceftazidime, and ofloxacin were variably effective, while cefaclor was the least effective agent.

Tampon sampling for diagnosis of bacterial vaginosis: a potentially useful way to detect genital infections?

Genital tract infections are important causes of ill health in developing countries, but diagnosis is difficult. Bacterial vaginosis (BV) was correctly diagnosed by using a vaginal specimen obtained by tampon sampling in 22 of 24 women (91.6%) for whom BV was diagnosed by Gram staining. The yield for other vaginal infections was higher (28% for Trichomonas vaginalis and 32.7% for Candida albicans) than it was for cervical infections (0% for Neisseria gonorrhoeae and 30% for Chlamydia trachomatis). Tampon sampling was acceptable to patients and may facilitate diagnosis of genital infections in developing countries.

Use of antibiotics to prevent preterm birth

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

Trichomonas vaginalis associated with low birth weight and preterm delivery. The Vaginal Infections and Prematurity Study Group

BACKGROUND

Several studies have suggested that pregnant women infected with Trichomonas vaginalis may be at increased risk of an adverse outcome.

GOAL

To evaluate prospectively the association between T. vaginalis and risk of adverse pregnancy outcome in a large cohort of ethnically diverse women.

STUDY DESIGN

At University-affiliated hospitals and antepartum clinics in five United States cities, 13,816 women (5,241 black, 4,226 Hispanic, and 4,349 white women) were enrolled at mid-gestation, tested for T. vaginalis by culture, and followed up until delivery.

RESULTS

The prevalence of T. vaginalis infection at enrollment was 12.6%. Race-specific prevalence rates were 22.8% for black, 6.6% for Hispanic, and 6.1% for white women. After multivariate analysis, vaginal infection with T. vaginalis at mid-gestation was significantly associated with low birth weight (odds ratio 1.3; 95% confidence interval 1.1 to 1.5), preterm delivery (odds ratio 1.3; 95% confidence interval 1.1 to 1.4), and preterm delivery of a low birth weight infant (odds ratio 1.4; 95% confidence interval 1.1 to 1.6). The attributable risk of T. vaginalis infection associated with low birth weight weight in blacks was 11% compared with 1.6% in Hispanics and 1.5% in whites.

CONCLUSIONS

After considering other recognized risk factors including co-infections, pregnant women infected with T. vaginalis at mid-gestation were statistically significantly more likely to have a low birth weight infant, to deliver preterm, and to have a preterm low birth weight infant. Compared with whites and Hispanics, T. vaginalis infection accounts for a disproportionately larger share of the low birth weight rate in blacks.

First antenatal visits and metronidazole

OBJECTIVE

We evaluated the timing of initial antenatal visits to better characterize possible use of metronidazole or other antimicrobials for common reproductive tract infections in early pregnancy.

STUDY DESIGN

We determined timing of initial antenatal evaluation in five busy and representative Denver, Colorado, practice settings (most recent 50 patients).

RESULTS

Most women were evaluated after completion of 9 weeks of pregnancy. Women seen in private settings received the initial visit earlier than did women in publicly supported clinics.

CONCLUSION

Pregnant women with a common reproductive tract infection and bacterial vaginosis can be "screened and treated" at the initial antenatal examination.

Rupture of the membranes and postpartum infection

The greatest risk of preterm prelabour rupture of membranes (PPROM) is preterm delivery. According to the Perinatal Information System of Slovenia there were 5.92% preterm deliveries in 1994. We studied 809 deliveries of less than 34 weeks of gestation in the Ljubljana Maternity, from 1992 to 1994; 33.7% of these started with PPROM. Risk factors for PPROM were conization, cerclage and use of antibiotics for any reason in current pregnancy. Amnionitis and febrile illness during labour increased with longer duration of PPROM but maternal postpartum infections did not. In neonates, more cases of lower Apgar scores after 1 and 5 min and more cases of suspected sepsis were found with the increased duration of PPROM. In Slovenia, with good facilities for transport in utero and good neonatal care, after PPROM it is best to transport the pregnant women to the third level center and then wait until labour starts or to recur to prompt delivery when maternal or fetal signs so require. From 1987 to 1993 there were 159264 deliveries in gestations equal to or over 34 weeks; 20.8% started with PROM. In our observational study we found the best results when labour was induced. There are, however, many disagreements about the management of (P)PROM.

Screening for bacterial vaginosis and cervicitis aimed at preventing premature delivery

OBJECTIVE

We performed screening and treatment of bacterial vaginosis and cervicitis during pregnancy for prevention of premature delivery. The incidence and the etiology of lower genital tract infections and premature delivery were examined to elucidate the effectiveness and problems of this trial.

METHODS

Three hundred sixty-five pregnant women who attended the obstetrical outpatient clinic in our hospital were included as subjects. The screening was done at prenatal-care visits around the 10th, 20th, and 30th gestational weeks.

RESULTS

Fifty-eight women were diagnosed as bacterial vaginosis and 54 women were successfully treated. Thirty-five women were diagnosed as cervicitis and all were cured. Nine women (2.5%) delivered before the 37th gestational week and 1 women delivered before the 35th gestational week because of cervical incompetence.

CONCLUSIONS

The treatment of bacterial vaginosis and cervicitis may prevent microbes in the lower genital tract from penetrating the intrauterine cavity and thereby reduce the incidence of premature delivery.

The pathobiology of premature rupture of membranes

Premature rupture of membranes arises from what are likely multifaceted and multistep pathogenic pathways. Pathophysiological processes may involve both endogenous and exogenous fetal and maternal factors. This article reviews and analyzes information regarding, first, the form and function of fetal membranes; second, how membranes physically fail (rupture) at term and preterm gestations; and third, evaluates if we can reduce risks of rupture using physiological understanding and evidence-based clinical studies.

Preterm labour and delivery

Preterm birth is a major cause of perinatal morbidity and mortality. It accounts for 5-10% of all births, and any treatment to prevent it could have a profound effect on neonatal outcome in both human and economic terms. The pathogenesis of both term and preterm birth remain poorly understood. Our ability to predict those at risk of preterm labour is also inaccurate, despite the creation of scoring systems, uterine activity monitoring, cervical ultrasound and several biochemical markers. Current drug therapies for preterm labour have not been shown in randomised controlled trials to significantly affect perinatal morbidity and mortality. Furthermore, most are associated with significant maternal or fetal side effects. Nitric oxide (NO) is a potent smooth muscle relaxant, produced when NO synthase acts on the amino acid L-arginine. Its presence has been demonstrated in human myometrium. We have conducted an observational study which has suggested that glyceryl trinitrate (GTN), and NO donor, may be effective in prolonging gestation. A randomised trial comparing GTN to intravenous ritodrine is currently recruiting patients; results will be available in the Spring of 1997. Few side effects have so far been encountered. Evidence suggests that GTN, an NO donor, should be a safe and effective tocolytic and early observations are encouraging; randomised trials currently underway should determine the significance of this breakthrough in the management of preterm labour.

Bacterial vaginosis in pregnancy and preterm birth: evidence from the literature

We review below the evidence from the literature about the relationships between bacterial vaginosis, its treatment and pregnancy outcome. The literature indicates that there is a well-defined association between the presence of bacterial vaginosis during pregnancy and the risk of premature membrane rupture and preterm birth. Less definite is the role of the treatment of such pathology in reducing the frequency of preterm birth and/or premature rupture of membranes. The results of the controlled clinical trials are not entirely consistent. Of the most studied therapies, clindamycin seems to have shown favourable results most consistently but the published data are limited to trials including just a few hundred subjects. Only the availability of further data from controlled clinical trials will clarify the role of such treatment for bacterial vaginosis in pregnancy.

Evaluation of a deoxyribonucleic acid probe for the detection of Trichomonas vaginalis in vaginal secretions

OBJECTIVE

Our purpose was to compare Affirm VP, a new deoxyribonucleic acid probe test, with standard "wet preparation" microscopic examinations and culture for the identification of Trichomonas vaginalis organisms in vaginal secretions.

STUDY DESIGN

We examined vaginal samples from 615 women with symptoms or signs of vaginitis for T. vaginalis using the deoxyribonucleic acid probe test, microscopic examination of wet preparations of vaginal secretions, and culture in modified Diamond's medium.

RESULTS

T. vaginalis was identified in specimens from 95 (15.4%) of the 615 patients. Cultures in Diamond's medium identified 93 (98%) of the 95 infected patients. Vaginal wet preparation identified 76 (80%) of the infected women. The deoxyribonucleic acid probe test detected 86 (90.5%) of the 95 infected patients. There was one false-positive deoxyribonucleic acid probe test (specificity 519/520: 99.8%).

CONCLUSION

The Affirm VP deoxyribonucleic acid probe test had a sensitivity of 90% and a specificity of 99.8% for the identification of T. vaginalis organisms in women with symptoms with a high prevalence of trichomoniasis. Such a nonculture test may be of considerable benefit in diagnosing T. vaginalis infections, especially in settings where microscopy, culture, or both are unavailable, inconvenient, or unreliably performed.

Salivary estriol as risk assessment for preterm labor: a prospective trial

OBJECTIVE

Increased understanding of human parturition allows for novel approaches to (1) identification of women at increased risk for preterm birth and (2) development and controlled testing of etiology-based strategies to prevent preterm birth.

STUDY DESIGN

Five hundred forty-two women were enrolled at five study sites in a prospective evaluation of salivary estriol in samples obtained weekly beginning at 22 weeks' gestation (Salest, Biex, Inc., Boulder, Colo.). Estriol concentrations were determined with a well-characterized enzyme-linked immunoassay. Women adjudged at either high risk or low risk for prematurity were evaluated through to delivery.

RESULTS

A total of 267 women submitted serial samples that were analyzed; 241 women with singleton pregnancies submitted sufficient samples. Twenty-three women with singleton fetuses went into idiopathic preterm labor (without prior rupture of membranes) and were delivered preterm (mean 35 weeks' gestation); 182 were delivered at term (> or = 37 weeks' gestation). Mean (geometric) estriol concentrations were higher from 24 to 34 weeks in women with singleton pregnancies delivering preterm (p < 0.05). A surge in estriol concentrations occurred approximately 3 weeks before the onset of labor in both women delivering at term and those delivering preterm. This increase occurred approximately 4 weeks earlier in women delivered preterm versus term. Receiver-operator curve analyses showed that exceeding a 2.3 ng/ml saliva estriol level was associated with occurrence of preterm labor (71% sensitivity, 77% specificity, 23% false-positive rate).

CONCLUSION

Detection of an early estriol surge or increased level (> or = 2.3 ng/ml) may be clinically helpful in identifying women at elevated risk for preterm labor and birth, allowing for evaluation of biologically based interventions in controlled trials.