Romero, R., Oyarzun, E., Mazor, M., Sirtori, M., Hobbins, J. C., & Bracken, M. (1989). Meta-analysis of the relationship between asymptomatic bacteriuria and preterm delivery/low birth weight. Obstetrics and gynecology, 73(4), 576-582.
Romero R, Oyarzun E, Mazor M, Sirtori M, Hobbins JC, Bracken M. Meta-analysis of the relationship between asymptomatic bacteriuria and preterm delivery/low birth weight. Obstet Gynecol. 1989;73(4):576-582.
Romero, R., et al. "Meta-analysis of the relationship between asymptomatic bacteriuria and preterm delivery/low birth weight." Obstetrics and gynecology, vol. 73, no. 4, 1989, pp. 576-582.
For EndNote, Zotero or Mendeley:
License
No open license is recorded for this paper. Reuse terms are set by the publisher.
Author affiliations
1 institution
Eunice Kennedy Shriver National Institute of Child Health and Human Development04byxyr05
Linked to ROR, the Research Organization Registry
Abstract
The relationship between asymptomatic bacteriuria and prematurity/low birth weight (LBW) is still a controversial issue, despite many studies. Meta-analysis, a research tool designed to analyze and combine the results of previous studies, may resolve this discrepancy among contradictory results of clinical trials. The purpose of this study was to examine the relationship between asymptomatic bacteriuria and preterm delivery/LBW using meta-analysis. Reports from the literature were classified according to study design into cohort or randomized-treatment control trials. Meta-analysis of cohort studies showed that untreated asymptomatic bacteriuria during pregnancy significantly increased rates of LBW and preterm delivery. Nonbacteriuric patients had only about two-thirds the risk (typical relative risk = 0.65; 95% confidence interval 0.57, 0.74) of LBW and half the risk (typical relative risk = 0.50; 95% confidence interval 0.36, 0.70) of preterm delivery of those with untreated asymptomatic bacteriuria. These reduced risks correspond to a 3.4 (confidence interval 1.8, 5.0) percentage-point difference in LBW and a 3.8 (1.1, 6.4) percentage-point difference in preterm delivery. The analysis of randomized clinical trials showed that antibiotic treatment significantly reduced the risk of LBW (typical relative risk = 0.56; 95% confidence interval 0.43, 0.73), with a substantial reduction of 6.4 (confidence interval 3.3, 9.5) percentage points in the rate of LBW. We conclude that clinical and epidemiologic evidence indicates a strong association between untreated asymptomatic bacteriuria and LBW/preterm delivery and that antibiotic treatment is effective in reducing the occurrence of LBW.
Bujold E et al., 2026·American Journal of Obstetrics and Gynecology·Free full text on PubMed Central
Normal uterine function depends on cyclical regeneration and the capacity to sustain pregnancy. A cesarean incision represents an injury to this remarkable organ. Although the uterus possesses exceptional healing potential, cesarean delivery increases the risk of secondary infertility, pelvic pain, uterine rupture, and abnormal placentation in subsequent pregnancies. The two most important determinants of successful hysterotomy healing after cesarean delivery are the location of the incision and the surgical technique used for closure. The anatomic site of entry-whether the corpus, lower uterine segment, or cervix-defines the tissue composition, vascularity, and contractility at the wound margins, which in turn influence how the scar remodels and withstands subsequent pregnancies. Surgical technique is also important. A robust body of experimental and clinical evidence demonstrates that restoring anatomic integrity by reapproximating uterine layers while excluding the endometrium produces stronger scars and reduces late complications. The rationale for excluding the endometrium is to prevent displacement of endometrial tissue into the myometrium and to avoid mucosal tearing against a foreign body (i.e. suture material), both of which predispose to defective healing. When the endometrium is incorporated, healing is often impaired, leading to niches or isthmoceles, adenomyosis, and endometriosis at the scar site. Over time, these defects have been recognized as contributors to abnormal bleeding, pelvic pain, infertility, uterine rupture, and placenta accreta spectrum disorders. Despite this evidence, single-layer closures that incorporate endometrium became widely adopted because of their speed and simplicity, while their long-term sequels were initially underappreciated. This has prompted renewed scrutiny of closure techniques, including comparisons of single-layer vs double-layer closure, locking vs nonlocking sutures, type of sutures, and the direction of suture. Collectively, the data show that optimal closure respects uterine anatomy, restores the natural alignment of tissues, and achieves hemostasis without compromising perfusion or strangulating tissues. Building on these principles, we herein describe a refined 3-layer closure. The first layer approximates decidua and junctional myometrium while excluding surface endometrium to prevent tissue entrapment and bacterial contamination. The second layer restores anatomic wall integrity by reapproximating the bulk of the myometrium, thereby reinforcing strength and distributing tension across the scar. The third layer reapproximates superficial myometrium and serosa, smoothing the uterine surface and reducing adhesions. This technique is not simply a return to traditional double-layer methods or an extension of single-layer practice, but rather a refinement that integrates lessons from visceral surgery and contemporary obstetric data. Its rationale is to restore anatomy, secure hemostasis without ischemia, and preserve long-term uterine function. While short-term safety appears comparable across closure methods, evidence increasingly indicates that long-term reproductive outcomes depend on how closure respects tissue biology. We argue that appropriate repair is more important than a fast repair: meticulous restoration of uterine anatomy should take precedence over operative speed. The enduring success of a hysterotomy repair depends on the surgical technique employed, as it directly affects women's future reproductive health.
Stafford IA et al., 2020·Am J Obstet Gynecol MFM·Free full text on PubMed Central
Incidence, risk factors, and perinatal morbidity and mortality rates related to amniotic fluid embolism remain a challenge to evaluate, given the presence of differing international diagnostic criteria, the lack of a gold standard diagnostic test, and a significant overlap with other causes of obstetric morbidity and mortality. The aims of this study were (1) to analyze the clinical features and outcomes of women using the largest United States-based contemporary international amniotic fluid embolism registry, and (2) to investigate differences in demographic and obstetric variables, clinical presentation, and outcomes between women with typical versus atypical amniotic fluid embolism, using previously published and validated criteria for the research reporting of amniotic fluid embolism. The AFE Registry is an international database established at Baylor College of Medicine (Houston, TX) in partnership with the Amniotic Fluid Embolism Foundation (Vista, CA) and the Perinatology Research Branch of the Division of Intramural Research of the NICHD/NIH/DHHS (Detroit, MI). Charts submitted to the registry between August 2013 and September 2017 were reviewed, and cases were categorized into typical, atypical, non-amniotic fluid embolism, and indeterminate, using the previously published and validated criteria for the research reporting of AFE. Demographic and clinical variables, as well as outcomes for patients with typical and atypical AFE, were recorded and compared. Student t tests, χ(2) tests, and analysis of variance tables were used to compare the groups, as appropriate, using SAS/STAT software, version 9.4. A total of 129 charts were available for review. Of these, 46% (59/129) represented typical amniotic fluid embolism and 12% (15/129) atypical amniotic fluid embolism, 21% (27/129) were non-amniotic fluid embolism cases with a clear alternative diagnosis, and 22% (28/129) had an uncertain diagnosis. Of the 27 women misclassified as an amniotic fluid embolism with an alternative diagnosis, the most common actual diagnosis was hypovolemic shock secondary to postpartum hemorrhage. Ten percent (6/59) of the women with typical amniotic fluid embolism had a pregnancy complicated by placenta previa, and 8% (5/61) had undergone in vitro fertilization to achieve pregnancy. In all, 66% (49/74) of the women with amniotic fluid embolism reported a history of atopy or latex, medication, or food allergy, compared to 34% of the obstetric population delivered at our hospital over the study period (P < .05). Our data represent a series of women with amniotic fluid embolism whose diagnosis has been validated by detailed chart review, using recently published and validated criteria for research reporting of amniotic fluid embolism. Although no definitive risk factors were identified, a high rate of placenta previa, reported allergy, and conceptions achieved through in vitro fertilization was observed.
To compare the diagnostic and prognostic performance of maternal blood C-reactive protein, white blood cell count (WBC), and temperature with that of amniotic fluid (AF) WBC in preterm labor. One hundred two women with preterm labor and intact membranes were studied. Maternal blood was collected to measure C-reactive protein concentration and WBC, and maternal temperature was also measured. Amniotic fluid obtained by amniocentesis was cultured and WBC determined. Receiver operating characteristic curve, logistic regression, and survival techniques were used for analysis. Patients with acute histologic chorioamnionitis had significantly higher median C-reactive protein concentration, WBC, temperature, and AF WBC than patients without this lesion (P < .05). Receiver operating characteristic curve and survival analysis demonstrated that an elevated C-reactive protein, WBC, or AF WBC was strongly associated with the likelihood of histologic chorioamnionitis, shorter interval to delivery, clinical chorioamnionitis, and neonatal morbidity (P < .05 for each). Of all the tests, AF WBC was the best independent predictor of a positive AF culture (odds ratio [OR] 16.8), interval to delivery (hazard ratio 5.7), clinical chorioamnionitis (OR 15.2), neonatal sepsis (OR 16.8), and significant neonatal complications (OR 7.4), after other confounding variables were adjusted (P < .05 for each). An elevated C-reactive protein, WBC, or AF WBC identified patients with intrauterine infection and adverse perinatal outcomes. Amniotic fluid WBC was a better independent predictor of these outcomes than C-reactive protein, WBC, or temperature.
Anti-Infective and Anti-Inflammatory Agents · Nonsteroidal Anti-Inflammatory Drugs
Although low-dose aspirin has been reported to reduce the incidence of preeclampsia among women at high risk for this complication, its efficacy and safety in healthy, nulliparous pregnant women are not known. We studied 3135 normotensive nulliparous women who were 13 to 26 weeks pregnant to determine whether treatment with aspirin reduced the incidence of preeclampsia. Of this group, 1570 women received 60 mg of aspirin per day and 1565 received placebo for the remainder of their pregnancies. We also evaluated the effect of aspirin on maternal and neonatal morbidity. Of the original group of 3135 women, 2985 (95 percent) were followed throughout pregnancy and the immediate puerperium. The incidence of preeclampsia was lower in the aspirin group (69 of 1485 women [4.6 percent]) than in the placebo group (94 of 1500 women [6.3 percent]) (relative risk, 0.7; 95 percent confidence interval, 0.6 to 1.0; P = 0.05), whereas the incidence of gestational hypertension was 6.7 and 5.9 percent, respectively. There were no significant differences in the infants' birth weight or in the incidence of fetal growth retardation, postpartum hemorrhage, or neonatal bleeding problems between the two groups. Subgroup analysis showed that preeclampsia occurred primarily in women whose initial systolic blood pressure was 120 to 134 mm Hg (incidence among such women, 5.6 percent in the aspirin group vs. 11.9 percent in the placebo group; P = 0.01). The incidence of abruptio placentae was greater among the women who received aspirin (11 women, vs. 2 in the placebo group; P = 0.01). Low-dose aspirin decreases the incidence of preeclampsia among nulliparous women, primarily through its effect in those who have elevated systolic blood pressure initially. This treatment does not decrease perinatal morbidity but increases the risk of abruptio placentae.
Premature birth causes high rates of neonatal morbidity and mortality. There are multiple causes of preterm birth. This article reviews the evidence linking subclinical infection and premature birth. Although maternal genital tract colonization with specific organisms has been inconsistently associated with preterm birth and/or premature rupture of membranes, some infections have been consistently associated with preterm delivery. The association of histologic chorioamnionitis with prematurity is a consistent finding, but the mechanisms require further study. The relationship between histologic chorioamnionitis infection and the chorioamnionitis of prematurity requires additional research. A varying number of patients in "idiopathic" preterm labor have positive amniotic fluid cultures (0% to 30%), but it is not clear whether infection preceded labor or occurred as a result of labor. Evidence of subclinical infection as a cause of preterm labor is raised by finding elevated maternal serum C-reactive protein and abnormal amniotic fluid organic acid levels in some patients in preterm labor. Biochemical mechanisms for preterm labor in the setting of infection are suggested by both in vitro and in vivo studies of prostaglandins and their metabolites, endotoxin and cytokines. Some, but by no means all, antibiotic trials conducted to date have reported decreases in prematurity. These results support the hypothesis that premature birth results in part from infection caused by genital tract bacteria. In the next few years, research efforts must be prioritized to determine the role of infection and the appropriate prevention of this cause of prematurity.
To review the evidence of effectiveness of prenatal care for preventing low birth weight (LBW). We reviewed original research, systematic reviews, meta-analyses and commentaries for evidence of effectiveness of the three core components of prenatal care--risk assessment, health promotion and medical and psychosocial interventions--for preventing the two constituents of preterm birth and intrauterine growth restriction (IUGR). Clinical risk assessment will fail to identify the majority of pregnancies at risk for preterm delivery or IUGR. While biophysical and biochemical modalities appear promising, their cost-effectiveness has not been demonstrated, nor can their routine use be recommended in the absence of effective interventions. Smoking cessation programs appear to be modestly effective. There is insufficient evidence to conclude a benefit for nutrition interventions, work counseling or preterm birth education. Only antenatal corticosteroid therapy has demonstrated a clear benefit in the tertiary prevention of preterm delivery. Interventions for which there is insufficient evidence to conclude a benefit include bed rest, hydration, sedation, cerclage, progesterone supplementation, antibiotic treatment, tocolysis without concomitant use of corticosteroids, thyrotropin-releasing hormone, psychosocial support and home visitation. Additionally, there is a paucity of evidence supporting the effectiveness of prenatal interventions, such as low-dose aspirin, bed rest, maternal hyperoxygenation, plasma volume expansion and antenatal fetal assessment, in preventing IUGR or its associated morbidity and mortality. Neither preterm birth nor IUGR can be effectively prevented by prenatal care in its present form. Preventing LBW will require reconceptualization of prenatal care as part of a longitudinally and contextually integrated strategy to promote optimal development of women's reproductive health not only during pregnancy, but over the life course.
C-reactive protein (CRP) is an acute-phase protein synthesized by the liver during the course of a large number of diseases. During gestation and parturition, progressively increasing numbers of gravida develop elevated levels up to 32, 48 to 80 per cent, respectively). These elevations in pregnancy, the nonspecificity of the test, and the inability to function as a reliable marker of fetal and/or maternal infectious morbidity have obscured the pragmatic utility of CRP determinations in both obstetrics and gynecology. Because of its biophysical kinetics, C-reactive protein determinations are best used as a monitoring parameter after the documentation of infection rather than as a diagnostic indicator of infection. They can provide valuable end titration points for termination of parenteral antibiotic therapy.
We tested the hypothesis that disturbed follicular development and disturbed luteal progesterone (P4) secretion are associated with reduced gonadotropin secretion in the early follicular phase by measuring pulsatile LH and FSH secretion at that time in 53 normally menstruating women. Three groups of women were identified on the basis of serum sex steroid concentrations (measured daily throughout the cycle) and luteal phase length. Group A (n = 27) had normal ovarian hormone secretion with peak serum estradiol (E2) concentrations of 440 pmol/L or more, peak serum P4 concentrations of 19 nmol/L or more, and luteal phase length of 9 days or more. Group B (n = 16) had normal peak serum E2 values, but peak serum P4 values less than 19 nmol/L and/or luteal phase length less than 9 days. Group C (n = 10) had peak serum E2 values below 440 pmol/L. Risk factors for the disturbances found in groups B and C were exercise and/or intermittent dieting. Compared to group A, both groups B and C had reduced mean serum LH concentrations (3.1 +/- 1.5 vs. 2.3 +/- 1.4 and 2.0 +/- 1.0 IU/L; P less than 0.05) and reduced LH pulse frequencies (5.2 +/- 2.1 vs. 3.5 +/- 1.8 and 3.3 +/- 2.3 pulses/12 h; P less than 0.02). LH amplitude was similar in all 3 groups. Mean serum FSH concentrations were slightly but not significantly lower in group C. We conclude that reduced gonadotropin secretion during the follicular phase may indeed affect E2 and P4 secretion at later stages of the menstrual cycle. The patterns of alteration associated with disturbed E2 and P4 secretion in normally menstruating women are similar to those that occur in women with hypothalamic amenorrhea.
Pregnancy › Preterm Birth › Infection and Inflammation · Birth and Delivery › Birth Outcomes › Maternal Morbidity · Research Methods › Evidence Synthesis › Meta-Analysis
Roberto Romero
R Romero
PMID 2927852 2927852 Romero et al. 1989, Romero 1989
Cite this article
Romero, R., Oyarzun, E., Mazor, M., Sirtori, M., Hobbins, J. C., & Bracken, M. (1989). Meta-analysis of the relationship between asymptomatic bacteriuria and preterm delivery/low birth weight. Obstetrics and gynecology, 73(4), 576-582.
Romero R, Oyarzun E, Mazor M, Sirtori M, Hobbins JC, Bracken M. Meta-analysis of the relationship between asymptomatic bacteriuria and preterm delivery/low birth weight. Obstet Gynecol. 1989;73(4):576-582.
Romero, R., et al. "Meta-analysis of the relationship between asymptomatic bacteriuria and preterm delivery/low birth weight." Obstetrics and gynecology, vol. 73, no. 4, 1989, pp. 576-582.
04byxyr05