Parvovirus B19 Infection in Pregnancy - Association of Ontario ...

CLINICAL PRACTICE GUIDELINE REVIEWNo. 8 March 2006Parvovirus B19 Infection in PregnancyThis guideline review has been reviewed and approved by the AOM Board of Directors on March 30, 2006.Principal AuthorLucia D’Amore, B.Sc.N., B.H.Sc., R.M., Burlington, ONAOM Clinical Practice Guideline Working GroupKathi Wilson, R.M., Chair, London, ONLynne-Marie Culliton, R.M., Owen Sound, ONKathelijne Keeren, R.M., Mississauga, ONTasha MacDonald, R.M., Toronto, ONAndrea Robertson, R.M., Hamilton, ONLisa Wishnefsky, R.M., Thornhill, ONGUIDELINE EVALUATEDCrane, J. and the Maternal-Fetal Medicine Committeeand Infectious Diseases Committee for Society ofObstetricians and Gynaecologists of Canada. ParvovirusB19 infection in pregnancy. JOGC 2002; 24(9): 727-743.INTRODUCTIONClinical practice guidelines are detailed statementsdeveloped by an organization, using a formal process, toassist clinicians and patients/clients in making decisionsabout appropriate health care for specific clinicalcircumstances. They are a means of translating theevidence from the current scientific literature intorecommendations for clinical practice with the goal ofimproving outcomes. Many groups in Canada are nowengaged in developing clinical practice guidelines forhealth care providers.In order to assist and support registered midwives inOntario to provide evidence-based care, and to provideinformed choice to women and their families, theAssociation of Ontario Midwives (AOM) reviews,evaluates and endorses, where applicable, existingclinical practice guidelines. Guidelines from otherprofessional organizations are evaluated and graded bymidwife authors utilizing the Appraisal of GuidelinesResearch and Evaluation (AGREE) Instrument. This toolprovides a systematic framework for assessing keycomponents of clinical practice guideline quality, withthe goal of assessing quality, validity, the method ofguideline development and identifying bias. Theevaluation of clinical practice guidelines for the AOMincludes discussion of issues which are specificallyrelated to the midwifery model of care and scope ofpractice.The goal of the Association of Ontario Midwives inevaluating current clinical practice guidelines is toprovide for midwives a set of comprehensive andaccessible guidelines. These guidelines, along withthose developed by the AOM, will guide midwives inclinical practice, assist with informed choice discussionsand aid midwives with practice protocol development.When using these guideline reviews, midwives areadvised that the review cannot be used in isolation, butmust be read in conjunction with the guideline in orderto achieve a full understanding of the recommendations.EVALUATIONThis is the link to the SOGC Guideline that is the subjectof this review:This guideline review reflects information consistent with the best practice as of the date issued and is subject to change. The information is not intended to dictate acourse of action. Local standards may cause additions to or modifications of this guideline. Such changes should be well documented by practice groups.The Association of Ontario Midwives respectfully acknowledges the financial support of the Ministry of Health and Long-Term Care in the development of this guideline.The views expressed in this guideline are strictly those of the Association of Ontario Midwives. No official endorsement by the Ministry of Health and Long-Term Careis intended or should be inferred.

http://sogc.medical.org/guidelines/pdf/ps119.pdfThe purpose of this clinical practice guideline is toreview the effects of parvovirus B19 on the pregnantwoman and fetus, and to outline the options formanagement of women who are exposed to or contractthis disease in pregnancy.The guideline was evaluated by the principal authorusing the AGREE instrument, and found to be of highoverall quality. The strengths were related to clinicaldata, quality, and applicability of recommendations. Aparticular strength of this clinical practice guideline as itrelates to midwifery is the clear delineation of prenatalmanagement and timing of referral to a tertiary carecentre. The main areas of weakness related to structuralomissions, including statements regarding potentialconflicts of interest, and lack of patient involvement inguideline development.OVERALL EVALUATION OF CLINICALPRACTICE GUIDELINE: RECOMMENDEDThe recommendations contained in the SOGC ClinicalPractice Guideline “Parvovirus B19 Infection inPregnancy” should be applied to midwifery practice.SUMMARY OF RECOMMENDATIONS1. Pregnant women exposed to, or who developsymptoms of parvovirus B19 infection should beassessed to determine if they are susceptible toinfection (nonimmune) or if they have a currentinfection, by determining their parvovirus B19 IgGand IgM status. (II-2A)2. If parvovirus B19 IgG is present and IgM is negative,the woman is immune and can be reassured that shewill not develop infection and that the virus will notadversely affect her pregnancy. (II-2A)3. If both parvovirus B19 IgG and IgM are negative(and the incubation period has passed), the womanis not immune and has not developed the infection.Although she may wish to minimize furtherexposure, leave from the workplace is controversialand is not routinely recommended. Further studiesare needed in this area. (III-B)4. If a recent parvovirus B19 infection has beendiagnosed in the woman, then referral to anobstetrician or a maternal-fetal medicine specialistshould be considered (III-B). The woman should becounselled regarding risks of fetal transmission, fetalloss, and hydrops. Serial ultrasounds should beperformed up to 8 to 12 weeks after infection todetect the development of hydrops. (III-B) Ifhydrops develops, referral to a maternal-fetalmedicine specialist should be made andconsideration should be given to fetal bloodsampling and intravascular transfusion. (II-2B)CURRENT RESEARCHA review of the literature was conducted usingMEDLINE. The major focus of the literature review wason research published from January 2002 through March2005, as this represents data that was released aftercompletion of the evaluated guideline.There has been some valuable literature publishedregarding the detection and management of parvovirusB19 in pregnancy since the publication of the SOGCclinical practice guideline.Although routine screening of women for parvovirusB19 susceptibility is not recommended in the reviewedguideline, much attention is paid to the identification ofat-risk populations. There is value in health careproviders having an awareness of the populations morelikely to encounter parvovirus B19 in pregnancy.Accordingly, there has been some debate as to thepotential value of routine screening of “high-risk”women for parvovirus B19 titers. A statistical analysisdone by Fean et al. 1 , clearly indicates that this practiceshould not be recommended. With 1-3% of pregnanciesbeing complicated by parvovirus B19 infection, and anoverall fetal mortality rate of 0.6%, it is not felt thatroutine screening in the first trimester would be a costeffective practice 1 . (III-B) As Fean states, “To prevent 1.5fetal losses, 50,000 women would need to be screenedregularly from the first trimester” 3 .Identifying women who have been exposed to, or showsymptoms of, parvovirus B19 infection has thus far beenthe only strategy for identifying fetuses at risk. A recentprospective study published by Simchen et al. 2 illustratesthe value in interpreting ultrasounds as they may relateto parvovirus B19 infection. The ultrasound detection ofa hyperechogenic focus in the fetal liver is a relativelycommon finding, with an incidence of 1:1000 2 . Althoughthis ultrasound finding is often associated with thepresence of other congenital abnormalities, its presencein isolation may indicate fetal infection 2 . There weretwo cases of fetal infection identified in this study inrelation to a hyperechogenic focus in the liver; one wasparvovirus B19 and the other was cytomegalovirus 2 .The findings of this study suggest that one may considerinvestigating potential parvovirus B19 infection in theAOM 2 March 2006

presence of a hyperechogenic focus in the fetal liver onultrasound. (II-2B)There has been new research published in regard to theseverity of parvovirus B19 infection after 20 weeksgestation, since the release of the SOGC guideline. TheSOGC clinical practice guideline states the fetal loss rateafter 20 weeks gestation to be 2.3%, as it relates tospontaneous demise and a hydropic presentation 3 .There is compelling evidence to suggest that parvovirusB19 is a more significant contributor to fetal morbidityand mortality after 20 weeks gestation than previouslybelieved. A study by Genen et al. 4 performedpathological testing on the placentas of neonates withunexplained systemic illness and poor neonataloutcomes. It was found that there was a high incidenceof previously undetected infection in placentalspecimens, with 4 % of specimens testing positive forparvovirus B19 4 .Also supporting these findings is a retrospectiveanalysis by Norbeck et al. 5 . This study examined bothplacental and fetal tissue in cases of intrauterine fetaldeath (IUFD) in late gestation. Parvovirus B19 in thisstudy was present in 14% of IUFD cases 5 . This suggeststhat the incidence of parvovirus B19 related intrauterinefetal death in the later half of pregnancy may be muchgreater than the 2.3% loss rate quoted in the SOGCclinical practice guideline. It is suggested that althoughthe risk of fetal hydrops decreases significantly after 20weeks gestation, the risk of fetal death does not 5 . Theabove studies suggest that routine parvovirus B19investigation in all cases of IUFD and unexplainedsystemic illness and poor neonatal outcome may bewarranted. (II-2A)ADDITIONAL MIDWIFERY CONSIDERATIONSMidwives are in an ideal position as primary health careproviders to ensure vigilance regarding the detectionand management of parvovirus B19 infection inpregnancy. The model of midwifery care permitsmidwives to counsel women regarding the existence ofparvovirus B19, to identify at risk populations, andensure the timely reporting of infectious diseaseexposure.in cases of intrauterine fetal death or unexplainedneonatal morbidity and mortality, if it is not alreadyincluded in routine investigations for these situations.Overall, the “Parvovirus B19 Infection in Pregnancy”clinical practice guideline is a very useful tool formidwives. It provides clear guidelines for timing andinterpretation of serology testing, as well as outliningindications for referral to an obstetrician and/ormaternal-fetal medicine specialist.CONCLUSIONAfter evaluation using the AGREE instrument andassessment of the current literature, the Association ofOntario Midwives recommends the application of theSOGC Clinical Practice Guideline, “Parvovirus B19Infection in Pregnancy” to midwifery practice, withthese additional recommendations:• Midwives should be aware of at risk populationswho may encounter parvovirus, but routinescreening within these populations is not warranted.• The ultrasound detection of hyperechogenic focus inthe fetal liver should prompt testing for ParvovirusB19. (II-2B)• Parvovirus B19 infection is associated with adverseoutcomes after 20 weeks gestation, and does indicatereferral to a maternal-fetal medicine specialist.REFERENCES1. Fean WS, Yee CF, Cincotta RB, Tilse M. Human parvovirus B19infection in pregnancy: should screening be offered to the lowriskpopulation? Aust N Z J Obstet Gynaecol 2002;42(4): 347-351.2. Simchen MJ, Toi A, Bona M, Alkazaleh F, Ryan G, Chitayat D.Fetal hepatic calcifications: prenatal diagnosis and outcome. Am JObstet Gynecol 2002;187(6):1617-22.3. Crane J. and the Maternal-Fetal Medicine Committee and theInfectious Diseases Committee for the Society of Obstetriciansand Gynaecologists of Canada. Parvovirus B19 infection inpregnancy. JOGC 2002;24(9):727-743.4. Genen L, Nuovo GJ, Krilov L, Davis JM. Correlation of in situdetection of infectious agents in the placenta with neonataloutcome. J Pediatr 2004;144(3):316-320.5. Norbeck O, Papadogiannakis N, Petersson K, Hirbod T, Broliden K,Tolfvenstam T. Revised clinical presentation of parvovirus B19-associated intrauterine fetal death. Clin Infect Dis2002;35(9):1032-1038.The significant body of literature published since theclinical practice guideline reviewed does suggestadditional recommendations should be made.Midwives should consider parvovirus B19 screening incases of hyperechogenic foci in the fetal liver identifiedby ultrasound. When working with the obstetric team,midwives should advocate for parvovirus B19 screeningAOM 3 March 2006