Screening for syphilis in pregnancy aims to detect infection in order to treat mothers and prevent transmission to babies.
8.6.1 BackgroundSyphilis is a sexually acquired infection caused by Treponema pallidum. In pregnancy, it can result in spontaneous miscarriage or stillbirth or cause congenital syphilis infection. Syphilis in pregnancy can be safely treated with antibiotics, which can prevent these complications (Walker 2001).
Syphilis in Australia
- Rates of diagnosis of syphilis — There were 1,292 diagnoses of infectious syphilis in 2009, with 10% among Aboriginal and Torres Strait Islander people, 86% among non-Indigenous people and a further 4% for which Indigenous status was not reported (NCHECR 2010). In the period 2005–09, the rate of diagnosis trebled among non-Indigenous Australians (from 2 to 6 per 100,000 population) and decreased from 31 to 25 per 100,000 Aboriginal and Torres Strait Islander population. Aboriginal and Torres Strait Islander women aged 29–40 years were diagnosed at 28 times the rate of non-Indigenous women in the same age group.
- Geographical distribution — In the non-Indigenous population, the majority of diagnoses occur in urban and regional areas (NCHECR 2010). In the Aboriginal and Torres Strait Islander population the rate of diagnosis increases exponentially as remoteness of residence increases — in 2009, the rate of diagnosis per 100,000 population was 10 in major cities, 32 in regional and 133 in remote areas (NCHECR 2010).
- Congenital syphilis — Australia is considered to be a country of low prevalence for congenital syphilis. From 2000 to 2009 there was a total of 116 cases of congenital syphilis, which is a rate of 0.1 per 100,000 or less per year (NNDSS website). Three cases of congenital syphilis were diagnosed in 2009 (NNDSS 2010).
- Risk factors — Ratios of male to female diagnoses indicate that transmission occurs predominantly through male homosexual contact in the non-Indigenous population and through heterosexual contact among Aboriginal and Torres Strait Islander people (NCHECR 2010). In 2009, 27% and 50% of diagnoses of infectious syphilis in the non-Indigenous and Aboriginal and Torres Strait Islander populations respectively occurred among people aged less than 30 years of age (NCHECR 2010). In a cohort of urban Aboriginal and Torres Strait Islander women, predictors for sexually transmitted infection were young age, harmful/hazardous alcohol use and unwanted pregnancy (Panaretto et al 2006).
Risks associated with syphilis in pregnancyMaternal syphilis infection results in congenital infection in at least two-thirds of cases (Zenker & Rolfs 1990; Chakraborty & Luck 2008; Woods 2009). Congenital infection can occur at any stage of maternal disease, including during incubation (Doroshenko et al 2006), as early as 9–10 weeks of pregnancy and at any subsequent time during pregnancy (Woods 2005).
Congenital syphilis is a serious condition that, if not fatal at a young age, can cause permanent impairment, debilitation and disfigurement (Chakraborty & Luck 2008; Richens & Mabey 2008). Pancreatitis and inflammation of the gastrointestinal tract are common (Woods 2005).
8.6.2 Syphilis screening
Summary of the evidence
Effectiveness of universal screeningUniversal syphilis screening programs have been shown to significantly increase the detection of pregnant women who have syphilis compared with selective screening of women considered to be a high-risk (Cameron et al 1997; Duthie et al 1990; Villar & Bergsjo 1997; Hurtig et al 1998). Based on convincing observational evidence, universal screening of pregnant women is recommended by the United States Preventive Services Task Force (USPST 2009; Wolff et al 2009), the World Health Organization (WHO 2004), the International Union against Sexually Transmitted Infections (IUSTI)(French et al 2009) and the United Kingdom national guidelines on the management of syphilis (Kingston et al 2008) as it decreases the proportion of babies with clinical symptoms of syphilis infection.
Universal screening for syphilis has been shown to be cost-effective (Garland & Kelly 1989; Abyad 1995; Cameron et al 1997; Connor et al 2000; Walker 2001) even in areas of low prevalence.
Recommendation - Grade B17. Routinely offer and recommend syphilis testing at the first antenatal visit as treating syphilis benefits both mother and baby.
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Type of testThere are two main classifications of serological tests for syphilis (NICE 2008):
- non-treponemal tests, which detect non-specific treponemal antibodies and include the Venereal Diseases Research Laboratory (VDRL) and rapid plasma reagin (RPR) tests; and
- treponemal tests, which detect specific treponemal antibodies and include EIAs, T. pallidum haemagglutination assay (TPHA) and the fluorescent treponemal antibody-absorbed test (FTA-abs).
- treponemal IgG EIA tests have high sensitivity (98%) and specificity (99%) at all stages of syphilis (except early primary syphilis), are useful for detecting syphilis antibodies in patients who are infected with HIV, and are comparable to the VDRL and TPHA combination in terms of sensitivity and specificity (Young et al 1989; 1992);
- non-treponemal tests may result in false negatives, particularly in very early or late syphilis, in patients with reinfection or those who are HIV positive, and have poor positive predictive value when used alone in low prevalence populations; and
- neither type of test will detect syphilis in its incubation stage (PHLS 1998).
Testing in rural and remote areasOn-site syphilis screening tests are being developed to allow results to be given and overcome the barrier to treating pregnant women who have to return to the clinic for tests results and treatments. The tests evaluated appear to have adequate sensitivity and specificity to be useful in remote areas or where equipment and lab equipment is not available (Mabey et al 2006; Marongoni et al 2005) and, in one study, reduced delays in treatment (Myer et al 2003).
Follow-up for women who test positive to syphilisNot all women who test positive will have syphilis, as these serological tests cannot distinguish between different treponematoses (eg syphilis, yaws, pinta and bejel). Therefore, positive results should be interpreted with caution. Following confirmation of a reactive specimen, a second specimen should be tested to verify the results and ensure correct identification of the woman.
Practice pointr. Because syphilis is a rare condition in most parts of Australia and a positive result does not necessarily mean that a woman has syphilis, expert advice regarding the care of women who test positive and their partners should be sought. Assessment/testing for other sexually transmitted infections in women with positive serology is advisable.
8.6.3 Practice summary — syphilis screeningWhen — Early in antenatal care
Who — Midwife; GP; obstetrician; Aboriginal and Torres Strait Islander health worker; multicultural health worker
- Discuss the reasons for syphilis screening — Explain that it is important to find out whether a woman has syphilis because of the effects that infection can have on the pregnancy and the baby.
- Document and follow-up — Note the results of syphilis screening in the woman’s record, including whether the syphilis is newly diagnosed or was previously treated. Have a follow-up system in place so that infected women receive timely treatment or referral.
- Take a holistic approach — If a woman is found to be infected with syphilis, other considerations include counselling, contact tracing, partner testing, testing for other sexually transmitted infections and follow-up.
8.6.4 ResourcesWA Health (2011) Syphilis in pregnancy. In: Guidelines for Managing Sexually Transmitted Infections. For more information please visit WA Department of Health website. (accessed 13 February 2011).
Walker GJA (2001) Antibiotics for syphilis diagnosed during pregnancy. Cochrane Database of Systematic Reviews 2001, Issue 3. Art. No.: CD001143. DOI: 10.1002/14651858.CD001143. For more information please visit The Cochrane Collaboration website.
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8.6.5 ReferencesAbyad A (1995) Cost-effectiveness of antenatal screening for syphilis. Health Care Women Int 16(4): 323–28.
Cameron ST, Thong KJ, Young H et al (1997) Routine antenatal screening for syphilis in Lothian: a study of the results 1988 to 1994. Brit J Obstet Gynaecol 104(6): 734-7.
Chakraborty R & Luck S (2008) Syphilis is on the increase: the implications for child health. Arch Dis Childhood 93(2): 105–09.
Connor N, Roberts J, Nicoll A (2000) Strategic options for antenatal screening for syphilis in the United Kingdom: a cost effectiveness analysis. J Med Screen 7(1): 7-13.
Doroshenko A, Sherrard J, Pollard AJ (2006) Syphilis in pregnancy and the neonatal period. Int J STD AIDS 17(4): 221–27.
Duthie SJ, King PA, Yung GL et al (1990) Routine serological screening for syphilis during pregnancy- disposable anachronism or fundamental necessity? Aust NZ J Obstet Gynaecol 30(1): 29–31.
French P, Gomberg M, Janier M et al (2009) IUSTI: 2008 European Guidelines on the Management of Syphilis. Int J STD AIDS 20(5): 300–09.
Garland SM & Kelly VN (1989) Is antenatal screening for syphilis worth while? Med J Aust 151(7): 368, 370, 372.
Hurtig AK, Nicoll A, Carne C et al (1998) Syphilis in pregnant women and their children in the United Kingdom: results from national clinician reporting surveys 1994-7. Brit Med J 317(7173): 1617–19.
Kingston M, French P, Goh Bet al (2008) UK National Guidelines on the Management of Syphilis 2008. Int J STD AIDS 19(11): 729–40.
Mabey D, Peeling RW, Ballard R et al (2006) Prospective, multicentre clinic-based evaluation of four rapid diagnostic tests for syphilis. STI 82(Suppl 5): v13–v16.
Marangoni A, Sambri V, Accardo S et al (2005) Evaluation of LIAISON Treponema Screen, a novel recombinant antigenbased chemiluminescence immunoassay for laboratory diagnosis of syphilis. Clin Diag Lab Immunol 12(10): 1231–34.
Myer L, Wilkinson D, Lombard C et al (2003) Impact of on-site testing for maternal syphilis on treatment delays, treatment rates, and perinatal mortality in rural South Africa: a randomised controlled trial. STI 79(3): 208–13.
NCHECR (2010) Bloodborne Viral and Sexually Transmitted Infections in Aboriginal and Torres Strait Islander People: Surveillance and Evaluation Report 2010. Sydney: National Centre in HIV Epidemiology and Clinical Research, The University of New South Wales.
NICE (2008) Antenatal Care. Routine Care for the Healthy Pregnant Woman. National Collaborating Centre for Women’s and Children’s Health. Commissioned by the National Institute for Health and Clinical Excellence. London: RCOG Press.
NNDSS (2010) Communicable Disease Surveillance: Preliminary Tables for 2009. For more information please visit Department of Health and Ageing website.
Panaretto KS, Lee HM, Mitchell MR et al (2006) Prevalence of sexually transmitted infections in pregnant urban Aboriginal and Torres Strait Islander women in northern Australia. Aust NZ J Obstet Gynaecol 46(3) 217–24.
PHLS (1998) Report to the National Screening Committee. Antenatal Syphilis Screening in the UK: A Systematic Review and National Options Appraisal with Recommendations. STD Section, HIV and STD Division, PHLS Communicable Disease Surveillance Centre, with the PHLS Syphilis Working Group. London: Public Health Laboratory Service.
Richens J & Mabey CW (2008) Sexually transmitted infections (excluding HIV). In: Cook G, Zumla A (eds) Manson’s Tropical Diseases. 22nd Edition. London: Saunders Elsevier.
USPSTF (2009) Screening for syphilis infection in pregnancy: US Preventive Services Task Force reaffirmation recommendation statement. Annals Int Med 150(10): 705–09.
Villar J & Bergsjo P (1997) Scientific basis for the content of routine antenatal care. I. Philosophy, recent studies, and power to eliminate or alleviate adverse maternal outcomes. Acta Obstet Gynecol Scand 76(1): 1–14.
Walker GJA (2001) Antibiotics for syphilis diagnosed during pregnancy. Cochrane Database of Systematic Reviews 2001, Issue 3. Art. No.: CD001143. DOI: 10.1002/14651858.CD001143.
Wolff T, Shelton E, Sessions C et al (2009) Screening for syphilis infection in pregnant women: evidence for the US Preventive Services Task Force reaffirmation recommendation statement. Annals Int Med 150(10): 710–16.
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Woods CR (2009) Congenital syphilis? Persisting pestilence. Pediatr Infect Dis J 28(6):536–37.
Woods CR (2005) Syphilis in children: congenital and acquired. Sem Pediatr Infect Dis 16(4): 245–57.
WHO (2004) Sexually Transmitted Infections Management Guidelines. 2004; For more information please visit World Health Organisation website.
Young H, Moyes A, McMillan A et al (1992) Enzyme immunoassay for anti-treponemal IgG: Screening of confirmatory test? J Clin Pathol 45: 37–41.
Young H, Moyes A, McMillan A et al (1989) Screening for treponemal infection by a new enzyme immunoassay. Genitourin Med 65: 72–78.
Zenker PN & Rolfs RT (1990) Treatment of syphilis, 1989. Rev Infect Dis 12 (Suppl 6): S590–S609.