Your Family Physician

The US Preventive Services Task Force (USPSTF) has reaffirmed its 2004 recommendation to screen all pregnant women for syphilis infection. The updated recommendation statement and an accompanying review of the underlying evidence are published in the May 19 issue of the Annals of Internal Medicine.

"In 2004, the USPSTF reviewed the evidence on screening for syphilis in pregnant women," write Ned Calonge, MD, MPH, from the Colorado Department of Public Health and Environment in Denver, and colleagues from the USPSTF, Agency for Healthcare Research and Quality (AHRQ), Rockville, Maryland.

"In 2008, the USPSTF performed a targeted literature review and determined that the net benefit of screening pregnant women continues to be well established. This literature update included a search for new and substantial evidence on the benefits of screening, harms of screening, and harms of treatment with penicillin."

Based on this review, which found no new substantial evidence that could change the 2004 recommendation, the USPSTF therefore reaffirmed its recommendation to screen all pregnant women for syphilis infection, which is a grade A recommendation.

Harms of failure to treat syphilis during pregnancy may include stillbirth, neonatal death, bone deformities, and neurologic impairment. Evidence is adequate that screening tests for syphilis can accurately detect infection. Universal screening of pregnant women for syphilis is associated with a lower proportion of infants who have clinical manifestations of syphilis infection, according to convincing observational evidence reviewed by the USPSTF.

Screening Process for and Treatment of Syphilis

Screening for and treatment of syphilis could theoretically cause possible harms, such as false-positive findings requiring further workup, unnecessary anxiety, and adverse events associated with antibiotic treatment. However, the USPSTF determined that the harm from screening is no greater than small, and it therefore concluded with high certainty that the net benefit of screening is substantial for pregnant women.

The recommended screening for syphilis consists of nontreponemal tests, either the Venereal Disease Research Laboratory test or the rapid plasma reagin test. If results are positive, these should be confirmed by a fluorescent treponemal antibody absorbed test or a Treponema pallidum particle agglutination test.

Screening should be performed at the first prenatal visit in all pregnant women, as well as in the third trimester and at delivery for women at high risk. Those at high risk include uninsured women, women living in poverty, sex workers, illicit drug users, women diagnosed with sexually transmitted diseases, and those living in communities with high syphilis morbidity.

For the treatment of syphilis during pregnancy, the Centers for Disease Control and Prevention (CDC) recommends parenteral benzathine penicillin G. Because evidence is limited regarding the efficacy or safety of alternative antibiotics in pregnancy, women who report penicillin allergies should be evaluated and desensitized to penicillin if necessary.

"Syphilis may be transmitted vertically, usually through the placenta; the risk for fetal infection increases with gestational age," write Tracy Wolff, MD, MPH, from the USPSTF, and coauthors of the accompanying evidence statement. "Vertical transmission may also occasionally occur during delivery if maternal genital lesions are present... "Although the overall rate of congenital syphilis has decreased significantly since the onset of the syphilis elimination plan in 1996, this recent increase is cause for concern, given that congenital syphilis is preventable."

Criteria and Evidence for Recommendations

The authors searched MEDLINE from January 1, 2003, through July 31, 2008, as well as recent systematic reviews, bibliographies of identified articles, and expert suggestions. Inclusion criteria for the review were English-language studies addressing 2 specific questions:

1. Does syphilis screening during pregnancy reduce the prevalence of congenital syphilis in neonates? Included studies that answered this question were randomized controlled trials, meta-analyses, systematic reviews, cohort studies, and ecologic studies.

2. Are there harms of syphilis screening or of penicillin treatment during pregnancy, either to women or to their infants? Included studies that answered this question were randomized controlled trials, meta-analyses, systematic reviews, cohort studies, case-control studies, and large case series.

Study design characteristics, enrollment criteria, demographic factors, and clinical outcomes data were extracted from each included study.

In a study of benefits, rates of congenital syphilis decreased after the implementation of a universal syphilis screening program for pregnant women.

Evidence regarding potential harms of screening for syphilis included 2 studies on screening accuracy, in which false-positive rates were less than 1%. The incidence of anaphylaxis after oral penicillin was 0.1 per 10,000 dispensings, based on a study using a large insurance claims database. A study from Hungary showed no link between use of oral penicillin during pregnancy and orofacial clefts in the offspring.

A limitation of the review was that it was a targeted search of the literature and could have failed to detect small studies on the benefits and harms of screening for syphilis during pregnancy. In addition, the review did not address interventions to improve rates of prenatal screening.

"New evidence from a study of universal screening supports previous evidence on the effectiveness of screening for syphilis in pregnancy to prevent congenital syphilis," the review authors conclude. "Harms include testing and follow-up for false-positive test results and adverse effects from penicillin treatment."

USPSTF recommendations are independent of the US government and should not be construed as an official position of the AHRQ or the US Department of Health and Human Services. The AHRQ supports the operations of the USPSTF, as mandated by the US Congress. The review authors have disclosed no relevant financial relationships.

Ann Intern Med. 2009;150:705-709, 710-716.

Clinical Context

Study Highlights

• The USPSTF recommends syphilis screening for all pregnant women, with high certainty of substantial net benefit.
• High certainty indicates consistent results from well-designed, well-conducted studies with unlikelihood that the conclusion will be affected by results from future studies.
• Factors that increase the risk for syphilis in pregnant women include lack of insurance, poverty, sex work, illicit drug use, other sexually transmitted diseases, and residing in communities with high syphilis morbidity.
• The prevalence of syphilis is higher in the southern United States, some metropolitan areas, and Hispanic and African American populations.
• Common initial nontreponemal screening tests are the Venereal Disease Research Laboratory and the rapid plasma reagin tests.
• Confirmatory tests include the fluorescent treponemal antibody absorbed and Treponema pallidum particle agglutination tests.
• Screening should occur at the first prenatal visit.
• Repeated testing is recommended for high-risk groups in the third trimester and at delivery.
• The CDC 2006 guidelines recommended treatment of syphilis with parenteral benzathine penicillin G.
• Women with penicillin allergies should be desensitized and treated with penicillin because of limited evidence on the efficacy or safety of alternative antibiotics.
• Posttreatment serologic tests are indicated to document decrease in titers.
• The American Academy of Pediatrics, American College of Obstetricians and Gynecologists, the CDC, and the American Academy of Family Physicians recommend syphilis screening for all pregnant women at the first prenatal visit.
• The American Academy of Pediatrics and the American College of Obstetricians and Gynecologists also recommend screening after exposure to the infected partner and at delivery and screening for high-risk women at the start of the third trimester.
• The CDC recommends repeated screening at 28 weeks and at delivery for women at high risk, women who reside in high-prevalence areas, women with no previous testing, or women with positive serologic test results in the first trimester.
• The American Academy of Family Physicians recommends repeated testing at 28 weeks and at delivery for high-risk women.
• 141 potentially relevant articles were identified from MEDLINE searches from January 1, 2003, to July 31, 2008; systematic reviews; reference lists; and expert suggestions.
• 5 English-language studies addressed the effects of syphilis screening on the incidence of congenital syphilis, harms or screening, or harms of penicillin treatment.
• 1 study in China reported that initiation of a universal syphilis screening program for pregnant women resulted in decreased rates of congenital syphilis from 54 to 22 cases per 100,000 pregnant women.
• 2 studies on screening accuracy found false-positive rates of up to 0.26% in women using Venereal Disease Research Laboratory testing and 0.91% in pregnant women using rapid plasma reagin testing.
• 1 study using an insurance claims database found that per 10,000 penicillin dispensings, the incidence was 0.1 for anaphylaxis, 0.2 for resuscitation, 2.1 for adverse effect, 2.4 for allergy, and 4.7 for any allergic reaction.
• 1 study reported that oral penamecillin in pregnant women was not linked with orofacial clefts in the offspring.

Clinical Implications

• The USPSTF recommends syphilis screening for all pregnant women.
• The substantial net benefit of syphilis screening in pregnant women is based on a reduced incidence of congenital syphilis in neonates, low false-positive rates of less than 1%, and a low incidence of harm from penicillin treatment.

Source : http://cme.medscape.com/viewarticle/703177?src=cmenews