0
Clinical Guidelines |

Screening for Bacterial Vaginosis in Pregnancy to Prevent Preterm Delivery: U.S. Preventive Services Task Force Recommendation Statement FREE

U.S. Preventive Services Task Force
[+] Article and Author Information

For a list of members of the U.S. Preventive Services Task Force, see the Appendix.


From the U.S. Preventive Services Task Force, Agency for Healthcare Research and Quality, Rockville, Maryland.


Disclaimer: Recommendations made by the USPSTF are independent of the U.S. government. They should not be construed as an official position of the Agency for Healthcare Research and Quality or the U.S. Department of Health and Human Services.

Financial Support: The USPSTF is an independent, voluntary body. The U.S. Congress mandates that the Agency for Healthcare Research and Quality support the operations of the USPSTF.

Requests for Single Reprints: Reprints are available from the USPSTF Web site (http://www.preventiveservices.ahrq.gov).


Ann Intern Med. 2008;148(3):214-219. doi:10.7326/0003-4819-148-3-200802050-00007
Text Size: A A A

Description: Update of the 2001 U.S. Preventive Services Task Force (USPSTF) recommendation on screening for bacterial vaginosis in pregnancy.

Methods: The USPSTF weighed the benefits and harms of screening for bacterial vaginosis in pregnancy by identifying new evidence addressing previously identified gaps from the 2001 USPSTF recommendation. Published literature on this topic was identified by using MEDLINE, Cochrane Library databases, the Database of Abstracts of Reviews of Effects, reference lists, and consultation with experts and was systematically reviewed. When data allowed, a series of meta-analyses (using new and 2001 report data) was done to estimate the pooled effect of treatment on preterm delivery (<37 weeks, <34 weeks, or <32 weeks) and on low birthweight and preterm, premature rupture of membranes.

Recommendation: Do not screen for bacterial vaginosis in pregnant women at low risk for preterm delivery. (D recommendation)Current evidence is insufficient to assess the balance of benefits and harms of screening for bacterial vaginosis in pregnant women at high risk for preterm delivery. (I statement)

The U.S. Preventive Services Task Force (USPSTF) makes recommendations about preventive care services for patients without recognized signs or symptoms of the target condition.

It bases its recommendations on a systematic review of the evidence of the benefits and harms and an assessment of the net benefit of the service.

The USPSTF recognizes that clinical or policy decisions involve more considerations than this body of evidence alone. Clinicians and policymakers should understand the evidence but individualize decision making to the specific patient or situation.

The USPSTF recommends against screening for bacterial vaginosis in asymptomatic pregnant women at low risk for preterm delivery. This is a grade D recommendation.

The USPSTF concludes that the current evidence is insufficient to assess the balance of benefits and harms of screening for bacterial vaginosis in asymptomatic pregnant women at high risk for preterm delivery. This is an I statement.

See the Clinical Considerations section for a discussion of risk assessment and suggestions for practice.

See the Figure for a summary of this recommendation and its impact on clinical practice. See Table 1 for a description of the USPSTF grades and Table 2 for a description of the USPSTF classification of levels of certainty about net benefit.

Grahic Jump Location
Figure.
Screening for bacterial vaginosis in pregnancy to prevent preterm delivery: clinical summary of a U.S. Preventive Services Task Force Recommendation.

For a summary of the evidence systematically reviewed in making these recommendations, the full recommendation statement, and supporting documents, go to http://www.preventiveservices.ahrq.gov. *The Centers for Disease Control and Prevention recommends 250 mg oral metronidazole 3 times daily for 7 days as the treatment of bacterial vaginosis in pregnancy.

Grahic Jump Location
Table Jump PlaceholderTable 1.  What the U.S. Preventive Services Task Force Grades Mean and Suggestions for Practice*
Table Jump PlaceholderTable 2.  U.S. Preventive Services Task Force Levels of Certainty Regarding Net Benefit
Rationale
Importance

The associations between bacterial vaginosis and adverse pregnancy outcomes, such as preterm delivery, are well documented.

Detection

Good-quality evidence indicates that screening tests (the Amsel clinical criteria or Gram stain) can detect bacterial vaginosis.

Benefits of Detection and Early Intervention
Asymptomatic Pregnant Women at Low Risk for Preterm Delivery.

No direct evidence indicates that screening for bacterial vaginosis reduces adverse health outcomes in asymptomatic pregnant women at low risk for preterm delivery. Good evidence indicates that treatment of bacterial vaginosis in these women lacks benefit.

Asymptomatic Pregnant Women at High Risk for Preterm Delivery.

No direct evidence indicates that screening for bacterial vaginosis reduces adverse health outcomes in asymptomatic pregnant women at high risk for preterm delivery. Evidence from good-quality studies is conflicting with respect to the benefits of treating bacterial vaginosis.

Harms of Detection and Early Treatment
Asymptomatic Pregnant Women at Low Risk for Preterm Delivery.

Evidence is poor (because studies are lacking) for harms of screening for bacterial vaginosis in asymptomatic pregnant women at low risk for preterm delivery. Evidence is fair that false-positive results from screening lead to harms due to treatment.

Asymptomatic Pregnant Women at High Risk for Preterm Delivery.

Evidence is poor (because studies are lacking) for harms of screening for bacterial vaginosis in asymptomatic pregnant women at high risk for preterm delivery. Studies on the harms of treatment have conflicting results.

USPSTF Assessment.

The USPSTF concludes that for asymptomatic pregnant women at low risk for preterm delivery, there is moderate certainty that screening for bacterial vaginosis has no net benefit.

The USPSTF concludes that for asymptomatic pregnant women at high risk for preterm delivery, the evidence is conflicting and the balance of benefits and harms cannot be determined.

Patient Population

This recommendation addresses screening for bacterial vaginosis in asymptomatic pregnant women.

Risk Assessment

Several factors have been associated with increased risk for preterm delivery. All of these associations are small to moderate. These factors include, but are not limited to, African-American race or ethnicity, body mass index less than 20 kg/m2, previous preterm delivery, vaginal bleeding, a short cervix (<2.5 cm), pelvic infection, and bacterial vaginosis. These factors can act in isolation or in combination. Furthermore, bacterial vaginosis in pregnancy is more common among African-American women, women of low socioeconomic status, and those who have previously delivered low-birthweight infants. For the purpose of the current recommendation, women were considered to be at low risk if they had no previous preterm delivery or other risk factors for preterm delivery (often these were nulliparous women). Women were considered to be at high risk if they had a previous preterm delivery.

Screening Tests

Bacterial vaginosis is diagnosed by using the Amsel clinical criteria or Gram stain. With the Amsel criteria, the clinical diagnosis is made by fulfilling 3 of 4 criteria: vaginal pH greater than 4.7, the presence of clue cells on wet mount, thin homogeneous discharge, and amine “fishy odor” when potassium hydroxide is added to the discharge.

Suggestions for Practice

This recommendation statement addresses screening for bacterial vaginosis in asymptomatic women. Treatment of symptomatic cases should be based on the clinical situation.

Treatment

Oral metronidazole and oral clindamycin, as well as vaginal metronidazole gel or clindamycin cream, are used to treat bacterial vaginosis. The optimal treatment regimen for pregnant women with bacterial vaginosis is unclear. Refer to the Centers for Disease Control and Prevention Web site for current treatment recommendations (http://www.cdc.gov/std/treatment/2006/vaginal-discharge.htm#vagdis2).

Research Needs

There are several evidence gaps in the literature on screening and treating bacterial vaginosis in asymptomatic pregnant women. A critical gap in the evidence exists in demonstrating a benefit of treatment in asymptomatic pregnant women at increased risk for preterm delivery. Available evidence on treatment benefit is conflicting. Additional research is needed to evaluate the benefit of screening and treating asymptomatic bacterial vaginosis in women at highest risk for preterm delivery. Research is also needed to assess which screening tests providers use to diagnose bacterial vaginosis in clinical practice and the accuracy of these tests. Finally, continued research is needed to determine the optimal treatment regimen for bacterial vaginosis.

Burden of Disease

Bacterial vaginosis is the most common lower genital tract syndrome among women of reproductive age. It involves an imbalance in the vaginal bacterial ecosystem, with a decrease in hydrogen peroxide–producing lactobacilli and an increase in Gardnerella vaginalis, anaerobes, and mycoplasmas. Studies have documented an association between bacterial vaginosis and the adverse pregnancy outcome of preterm delivery. This epidemiologic evidence has been used as a rationale for screening asymptomatic pregnant women for bacterial vaginosis.

The literature demonstrates a prevalence of bacterial vaginosis ranging from 9% to 23% in studies conducted in academic medical centers or public hospitals. The prevalence of bacterial vaginosis in pregnant women in community clinical settings is not well studied. Bacterial vaginosis in pregnancy is more common among African-American women, women of low socioeconomic status, and women who have previously delivered low-birthweight infants.

The natural history of bacterial vaginosis in pregnant women has shown that up to 50% of cases resolve spontaneously during pregnancy. Because bacterial vaginosis may not continue throughout pregnancy, whether to screen and treat multiple times, and optimal screening intervals, are not known (1).

Scope of Review

The USPSTF updated its 2001 recommendation on bacterial vaginosis. The goal was to review the literature and to identify new evidence addressing previously identified gaps, such as the characterization of patients most likely to benefit from screening and the optimal timing of screening and treatment on pregnancy outcomes.

Accuracy of Screening Tests

Bacterial vaginosis is diagnosed by using the Amsel clinical criteria or Gram stain. The reliability of the Amsel clinical criteria in community practice is unknown. Gram stain of vaginal discharge may be a more reliable means of diagnosing bacterial vaginosis and offers the added ability to quantify and classify bacterial load. As a result, Gram stain has been the primary means used to diagnose bacterial vaginosis in research studies. However, Gram stain is less commonly used in clinical practice because of the need for laboratory facilities and the delay in receiving diagnostic results (1).

No studies of diagnostic assessment in the clinical practice setting were found in the literature. Most studies compared the application of all Amsel clinical criteria with Gram stain in a research setting. In the 2001 USPSTF review, comparisons of the Amsel clinical criteria with Gram stain yielded sensitivities from 62% to 97% and specificities from 66% to 95%, with Gram stain as the criterion standard in diagnosing bacterial vaginosis (2).

The 2001 USPSTF evidence review stated that the preferred screening test would predict pregnancy outcomes with the most accuracy. The current update identified studies that evaluated diagnostic tests in predicting preterm birth (1). A poor-quality meta-analysis (11 studies) showed no difference in accuracy between clinical criteria and Gram stain in preterm delivery (3).

Effectiveness of Early Detection and Treatment

Because the evidence is poor, there is no known benefit of early detection in either low-risk or high-risk, asymptomatic pregnant women.

The USPSTF found good evidence of a lack of benefit from treatment in low-risk, asymptomatic pregnant women. Randomized clinical trials of good quality pooled with 2001 report data showed no treatment effects for asymptomatic women at low risk for preterm delivery at less than 37 weeks (1).

Randomized, controlled trials of good quality had conflicting results about treatment benefit in high-risk, asymptomatic pregnant women. There was statistically significant heterogeneity among the trials (P < 0.001). Three of the 5 trials reported a statistically significant benefit from treatment, 1 showed a statistically significant harm from treatment, and 1 showed no benefit (48).

Potential Harms of Screening and Treatment

No studies directly addressed the harms of screening (for example, increased risk for preterm delivery). The effects of treatment in women with a misdiagnosis of bacterial vaginosis have been indirectly studied and were documented in the 2001 review (2). Two studies of women who tested negative for bacterial vaginosis and received treatment compared with women who tested negative and were not treated found an increase in preterm delivery at less than 34 weeks in the group who tested negative and were treated (7, 9). A recent study also confirmed the potential harm of misdiagnosis (greater spontaneous preterm delivery at <37 weeks) in women who tested negative for bacterial vaginosis and were treated versus the placebo group, but this finding did not reach statistical significance (10).

Estimate of Magnitude of Net Benefit

In low-risk, asymptomatic pregnant women, the USPSTF found no known benefits of detection and early treatment and concluded with moderate certainty that screening has no net benefit. Given the lack of net benefit, the USPSTF recommends against routine screening for bacterial vaginosis in low-risk, pregnant women. The results of studies assessing bacterial vaginosis treatment in high-risk, asymptomatic pregnant women are conflicting. As a result of this significant evidence gap, the USPSTF concluded that the evidence is insufficient to make a recommendation about screening for bacterial vaginosis in high-risk pregnant women.

The Centers for Disease Control and Prevention (11), the American College of Obstetricians and Gynecologists (12), the Cochrane Pregnancy and Childbirth Group (13), the British Association for Sexual Health and HIV/Clinical Effectiveness Group (14), and the American Academy of Family Physicians make similar recommendations about screening and treatment of pregnant women with bacterial vaginosis (15). All recommend against routine screening for bacterial vaginosis in asymptomatic pregnant women. With respect to women at high risk for preterm delivery, the Centers for Disease Control and Prevention, American College of Obstetricians and Gynecologists, the American Academy of Family Physicians, and British Association for Sexual Health and HIV state that there may be high-risk women for whom screening and treatment may be beneficial. The Centers for Disease Control and Prevention does not recommend the use of clindamycin vaginal cream in the second half of pregnancy.

Nygren P, Bougatsos C, Freeman M, Helfand M.  Screening and Treatment for Bacterial Vaginosis in Pregnancy: Systematic Review to Update the 2001 U.S. Preventive Services Task Force Recommendation Statement Prepared for the Agency for Healthcare Research and Quality by the Oregon Evidence-based Practice Center under Contract No. 290-02-0024. Evidence Synthesis No. 57. AHRQ Publication No. 08-05106. Rockville, MD: Agency for Healthcare Research and Quality; 2008.
 
Guise JM, Mahon SM, Aickin M, Helfand M, Peipert JF, Westhoff C.  Screening for bacterial vaginosis in pregnancy. Am J Prev Med. 2001; 20:62-72. PubMed
CrossRef
 
Honest H, Bachmann LM, Knox EM, Gupta JK, Kleijnen J, Khan KS.  The accuracy of various tests for bacterial vaginosis in predicting preterm birth:a systematic review. BJOG. 2004; 111:409-22. PubMed
 
Carey JC, Klebanoff MA, Hauth JC, Hillier SL, Thom EA, Ernest JM. et al.  Metronidazole to prevent preterm delivery in pregnant women with asymptomatic bacterial vaginosis. National Institute of Child Health and Human Development Network of Maternal-Fetal Medicine Units. N Engl J Med. 2000; 342:534-40. PubMed
 
Odendaal HJ, Popov I, Schoeman J, Grové D.  Preterm labour—is Mycoplasma hominis involved? S Afr Med J. 2002; 92:235-7. PubMed
 
McDonald HM, O'Loughlin JA, Vigneswaran R, Jolley PT, Harvey JA, Bof A. et al.  Impact of metronidazole therapy on preterm birth in women with bacterial vaginosis flora (Gardnerella vaginalis): a randomised, placebo controlled trial. Br J Obstet Gynaecol. 1997; 104:1391-7. PubMed
 
Hauth JC, Goldenberg RL, Andrews WW, DuBard MB, Copper RL.  Reduced incidence of preterm delivery with metronidazole and erythromycin in women with bacterial vaginosis. N Engl J Med. 1995; 333:1732-6. PubMed
 
Morales WJ, Schorr S, Albritton J.  Effect of metronidazole in patients with preterm birth in preceding pregnancy and bacterial vaginosis: a placebo-controlled, double-blind study. Am J Obstet Gynecol. 1994;171:345-7; discussion 348-9. [PMID: 8059811]
 
Vermeulen GM, Bruinse HW.  Prophylactic administration of clindamycin 2% vaginal cream to reduce the incidence of spontaneous preterm birth in women with an increased recurrence risk: a randomised placebo-controlled double-blind trial. Br J Obstet Gynaecol. 1999; 106:652-7. PubMed
 
Andrews WW, Goldenberg RL, National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network.  What we have learned from an antibiotic trial in fetal fibronectin positive women. Semin Perinatol. 2003; 27:231-8. PubMed
 
Centers for Disease Control and Prevention (CDC).  Sexually transmitted disease treatment guidelines 2006 - Diseases characterized by vaginal discharge. MMWR Recomm Rep. 2006;55(RR-11):50-2. Accessed athttp://www.cdc.gov/std/treatment/2006/vaginal-discharge.htm#vagdis2on 12 April 2007.
 
American College of Obstetricians and Gynecologists.  ACOG Practice Bulletin. Assessment of risk factors for preterm birth. Clinical management guidelines for obstetrician-gynecologists. Number 31, October 2001. (Replaces Technical Bulletin number 206, June 1995; Committee Opinion number 172, May 1996; Committee Opinion number 187, September 1997; Committee Opinion number 198, February 1998; and Committee Opinion number 251, January 2001). Obstet Gynecol. 2001; 98:709-16. PubMed
 
McDonald H, Brocklehurst P, Parsons J.  Antibiotics for treating bacterial vaginosis in pregnancy. Cochrane Database Syst. Review 1998, Issue 4. Art. No.: CD000262. DOI: 10.1002/14651858.CD000262.pub3. Accessed athttp://www.cochrane.org/reviews/en/ab000262.htmlon 12 April 2007.
 
British Association for Sexual Health and HIV (BASHH) and the Clinical Effectiveness Group (CEG).  Revised national guideline for the management of bacterial vaginosis. Accessed athttp://www.bashh.org/guidelines/2006/bv_final_0706.pdfon 29 November 2007.
 
American Academy of Family Physicians (AAFP).  Recommendations for clinical preventive services—bacterial vaginosis. Accessed athttp://www.aafp.org/online/en/home/clinical/exam/a-e.htmlon 12 April 2007.
 
Appendix: U.S. Preventive Services Task Force

Members of the U.S. Preventive Services Task Force† are Ned Calonge, MD, MPH, Chair (Colorado Department of Public Health and Environment, Denver, Colorado); Diana B. Petitti, MD, MPH, Vice Chair (Keck School of Medicine, University of Southern California, Sierra Madre, California); Thomas G. DeWitt, MD (Children's Hospital Medical Center, Cincinnati, Ohio); Leon Gordis, MD, MPH, DrPH (Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland); Kimberly D. Gregory, MD, MPH (Cedars-Sinai Medical Center, Los Angeles, California); Russell Harris, MD, MPH (University of North Carolina School of Medicine, Chapel Hill, North Carolina); Kenneth W. Kizer, MD, MPH (National Quality Forum, Washington, DC); Michael L. LeFevre, MD, MSPH (University of Missouri School of Medicine, Columbia, Missouri); Carol Loveland-Cherry, PhD, RN (University of Michigan School of Nursing, Ann Arbor, Michigan); Lucy N. Marion, PhD, RN (Medical College of Georgia, Augusta, Georgia); Virginia A. Moyer, MD, MPH (University of Texas Health Science Center, Houston, Texas); Judith K. Ockene, PhD (University of Massachusetts Medical School, Worcester, Massachusetts); George F. Sawaya, MD (University of California, San Francisco, San Francisco, California); Albert L. Siu, MD, MSPH (Mount Sinai Medical Center, New York, New York); Steven M. Teutsch, MD, MPH (Merck & Company, West Point, Pennsylvania); and Barbara P. Yawn, MD, MSPH, MSc (Olmsted Medical Center, Rochester, Minnesota).

†This list includes members of the Task Force at the time this recommendation was finalized. For a list of current Task Force members, go to http://www.ahrq.gov/clinic/uspstfab.htm.

Figures

Grahic Jump Location
Figure.
Screening for bacterial vaginosis in pregnancy to prevent preterm delivery: clinical summary of a U.S. Preventive Services Task Force Recommendation.

For a summary of the evidence systematically reviewed in making these recommendations, the full recommendation statement, and supporting documents, go to http://www.preventiveservices.ahrq.gov. *The Centers for Disease Control and Prevention recommends 250 mg oral metronidazole 3 times daily for 7 days as the treatment of bacterial vaginosis in pregnancy.

Grahic Jump Location

Tables

Table Jump PlaceholderTable 1.  What the U.S. Preventive Services Task Force Grades Mean and Suggestions for Practice*
Table Jump PlaceholderTable 2.  U.S. Preventive Services Task Force Levels of Certainty Regarding Net Benefit

References

Nygren P, Bougatsos C, Freeman M, Helfand M.  Screening and Treatment for Bacterial Vaginosis in Pregnancy: Systematic Review to Update the 2001 U.S. Preventive Services Task Force Recommendation Statement Prepared for the Agency for Healthcare Research and Quality by the Oregon Evidence-based Practice Center under Contract No. 290-02-0024. Evidence Synthesis No. 57. AHRQ Publication No. 08-05106. Rockville, MD: Agency for Healthcare Research and Quality; 2008.
 
Guise JM, Mahon SM, Aickin M, Helfand M, Peipert JF, Westhoff C.  Screening for bacterial vaginosis in pregnancy. Am J Prev Med. 2001; 20:62-72. PubMed
CrossRef
 
Honest H, Bachmann LM, Knox EM, Gupta JK, Kleijnen J, Khan KS.  The accuracy of various tests for bacterial vaginosis in predicting preterm birth:a systematic review. BJOG. 2004; 111:409-22. PubMed
 
Carey JC, Klebanoff MA, Hauth JC, Hillier SL, Thom EA, Ernest JM. et al.  Metronidazole to prevent preterm delivery in pregnant women with asymptomatic bacterial vaginosis. National Institute of Child Health and Human Development Network of Maternal-Fetal Medicine Units. N Engl J Med. 2000; 342:534-40. PubMed
 
Odendaal HJ, Popov I, Schoeman J, Grové D.  Preterm labour—is Mycoplasma hominis involved? S Afr Med J. 2002; 92:235-7. PubMed
 
McDonald HM, O'Loughlin JA, Vigneswaran R, Jolley PT, Harvey JA, Bof A. et al.  Impact of metronidazole therapy on preterm birth in women with bacterial vaginosis flora (Gardnerella vaginalis): a randomised, placebo controlled trial. Br J Obstet Gynaecol. 1997; 104:1391-7. PubMed
 
Hauth JC, Goldenberg RL, Andrews WW, DuBard MB, Copper RL.  Reduced incidence of preterm delivery with metronidazole and erythromycin in women with bacterial vaginosis. N Engl J Med. 1995; 333:1732-6. PubMed
 
Morales WJ, Schorr S, Albritton J.  Effect of metronidazole in patients with preterm birth in preceding pregnancy and bacterial vaginosis: a placebo-controlled, double-blind study. Am J Obstet Gynecol. 1994;171:345-7; discussion 348-9. [PMID: 8059811]
 
Vermeulen GM, Bruinse HW.  Prophylactic administration of clindamycin 2% vaginal cream to reduce the incidence of spontaneous preterm birth in women with an increased recurrence risk: a randomised placebo-controlled double-blind trial. Br J Obstet Gynaecol. 1999; 106:652-7. PubMed
 
Andrews WW, Goldenberg RL, National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network.  What we have learned from an antibiotic trial in fetal fibronectin positive women. Semin Perinatol. 2003; 27:231-8. PubMed
 
Centers for Disease Control and Prevention (CDC).  Sexually transmitted disease treatment guidelines 2006 - Diseases characterized by vaginal discharge. MMWR Recomm Rep. 2006;55(RR-11):50-2. Accessed athttp://www.cdc.gov/std/treatment/2006/vaginal-discharge.htm#vagdis2on 12 April 2007.
 
American College of Obstetricians and Gynecologists.  ACOG Practice Bulletin. Assessment of risk factors for preterm birth. Clinical management guidelines for obstetrician-gynecologists. Number 31, October 2001. (Replaces Technical Bulletin number 206, June 1995; Committee Opinion number 172, May 1996; Committee Opinion number 187, September 1997; Committee Opinion number 198, February 1998; and Committee Opinion number 251, January 2001). Obstet Gynecol. 2001; 98:709-16. PubMed
 
McDonald H, Brocklehurst P, Parsons J.  Antibiotics for treating bacterial vaginosis in pregnancy. Cochrane Database Syst. Review 1998, Issue 4. Art. No.: CD000262. DOI: 10.1002/14651858.CD000262.pub3. Accessed athttp://www.cochrane.org/reviews/en/ab000262.htmlon 12 April 2007.
 
British Association for Sexual Health and HIV (BASHH) and the Clinical Effectiveness Group (CEG).  Revised national guideline for the management of bacterial vaginosis. Accessed athttp://www.bashh.org/guidelines/2006/bv_final_0706.pdfon 29 November 2007.
 
American Academy of Family Physicians (AAFP).  Recommendations for clinical preventive services—bacterial vaginosis. Accessed athttp://www.aafp.org/online/en/home/clinical/exam/a-e.htmlon 12 April 2007.
 

Letters

NOTE:
Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).

Comments

Submit a Comment
Were inclusion criteria for the USPSTF review on BV treatment during pregnancy consistently applied?
Posted on September 11, 2009
Emilia H. Koumans
Division of STD Prevention, Centers for Disease Control and Prevention
Conflict of Interest: None Declared

Dear Editors,

In their update and review "Evidence on the benefits and harms of screening and treating pregnant women who are asymptomatic for bacterial vaginosis: an update review for the U.S. Preventive Services Task Force" (1), Dr. Nygren and colleagues reviewed the English-language literature using a variety of methods to identify randomized trials with pregnancy outcome data in women who were asymptomatic for bacterial vaginosis (2000- 2007). In their analysis of 14 trials, they found insufficient evidence to recommend screening for high risk women, and no benefit for average risk women or low risk women. They recommended that low risk women not be screened.

The inclusion criteria for pregnant women, the criteria used to define bacterial vaginosis, gestational age at testing and treatment, and therapy provided varied widely between studies. Dr. Nygren and colleagues state that inclusion criteria for the meta-analysis were trials that evaluated screening, treatment, pregnancy outcomes, or adverse effects for asymptomatic pregnant women with bacterial vaginosis. However, it is unclear whether they were consistently applied. For example, Odendaal et al. (2) did not report on symptoms, whereas the other included trials did. Of the 14 trials, only two used Nugent's (3) Gram stain score of 7-10 to define BV (4, 5). Other trials used a variety of combinations of clinical and Gram stain criteria, and one trial used Nugent's Gram stain score of 7 -10 (BV) and abnormal flora (score 4-6) (6). Some trials found a benefit (6), and some did not (4).

Ugwumadu et al. reported the results of a double-blinded, randomized, placebo-controlled trial of oral clindamycin for the treatment of bacterial vaginosis (Nugent's score of 7-10) or abnormal vaginal (score of 4-6) flora by Gram stain among asymptomatic women in the Lancet in 2003 (7). This trial found that treatment significantly reduced spontaneous preterm delivery (5% treatment vs 12% placebo) and late miscarriage (1% treatment vs 4% placebo). However, it was not included in the review by Nygren et al.

In Figure 2 of the US Preventative Services Task Force review, the authors provide the reasons for excluding studies from the meta-analyses, but do not provide references for the 13 excluded trials. None of the reasons appears to apply to the trial by Ugwumadu and colleagues; it is not clear why this was not included.

We could not find the cited Appendix or Appendix figure at www.annals.org to review the methodology for calculating the estimates of benefits and harms of screening and treatment. We wonder how the figures would change if the results of the Uguwumadu trial were included and the Odendaal trial excluded.

References

1. Nygren P, Fu R, Freeman M, Bougatsos C, Klebanoff M, Guise JM. Evidence on the benefits and harms of screening and treating pregnant women who are asymptomatic for bacterial vaginosis: an update review for the U.S. Preventive Services Task Force. Ann of Int Med 2008; 148(3):220- 33.

2. Odendaal HJ, Popov I, Schoeman J, Smith M, Grove D. Preterm labour --is bacterial vaginosis involved? S Afr Med J 2002; 92(3):231-4.

3. Nugent RP, Krohn MA, Hillier SL. Reliability of diagnosing bacterial vaginosis is improved by a standardized method of gram stain interpretation. J Clin Micro 1991; 29(2):297"“301.

4. Guaschino S, Ricci E, Franchi M, Frate GD, Tibaldi C, Santo DD, Ghezzi F, Benedetto C, Seta FD, Parazzini F. Treatment of asymptomatic bacterial vaginosis to prevent pre-term delivery: a randomised trial. European Journal of Obstetrics, Gynecology, & Reproductive Biology 2003;110(2):149-52.

5. Kiss H, Petricevic L, Husslein P. Prospective randomized controlled trial of an infection screening programme to reduce the rate of preterm delivery. BMJ 2004;329:371-376.

6. Lamont RF, Duncan SLB, Mandal D, Bassett P. Intravaginal clindamycin to reduce preterm birth in women with abnormal genital tract flora. Obstet Gyncol 2003;101:516-522.

7. Ugwumadu A, Manyonda I, Reid F, Hay P. Effect of early oral clindamycin on late miscarriage and preterm delivery in asymptomatic women with abnormal vaginal flora and bacterial vaginosis: a randomized controlled trial. Lancet 2003;361:983-988.

Conflict of Interest:

None declared

Submit a Comment

Supplements

Supplemental Content
Recommendation Summary

Summary for Patients

Screening Pregnant Women for Bacterial Vaginosis: U.S. Preventive Services Task Force Recommendations

The summary below is from the full reports titled “Screening for Bacterial Vaginosis in Pregnancy to Prevent Preterm Delivery: U.S. Preventive Services Task Force Recommendation Statement” and “Evidence on the Benefits and Harms of Screening and Treating Pregnant Women Who Are Asymptomatic for Bacterial Vaginosis: An Update Review for the U.S. Preventive Services Task Force.” They are in the 5 February 2008 issue of Annals of Internal Medicine (volume 148, pages 214-219 and 220-233). The first report was written by the U.S. Preventive Services Task Force; the second report was written by P. Nygren, R. Fu, M. Freeman, C. Bougatsos, M. Klebanoff, and J.M. Guise.

Read More...

Clinical Slide Sets

Terms of Use

The In the Clinic® slide sets are owned and copyrighted by the American College of Physicians (ACP). All text, graphics, trademarks, and other intellectual property incorporated into the slide sets remain the sole and exclusive property of the ACP. The slide sets may be used only by the person who downloads or purchases them and only for the purpose of presenting them during not-for-profit educational activities. Users may incorporate the entire slide set or selected individual slides into their own teaching presentations but may not alter the content of the slides in any way or remove the ACP copyright notice. Users may make print copies for use as hand-outs for the audience the user is personally addressing but may not otherwise reproduce or distribute the slides by any means or media, including but not limited to sending them as e-mail attachments, posting them on Internet or Intranet sites, publishing them in meeting proceedings, or making them available for sale or distribution in any unauthorized form, without the express written permission of the ACP. Unauthorized use of the In the Clinic slide sets will constitute copyright infringement.

Toolkit

Want to Subscribe?

Learn more about subscription options

Advertisement
Related Articles
Related Point of Care
Topic Collections
PubMed Articles

Want to Subscribe?

Learn more about subscription options

Forgot your password?
Enter your username and email address. We'll send you a reminder to the email address on record.
(Required)
(Required)